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1
Usman, Ediar. "THE GEOCHEMICAL CHARACTERISTIC OF MAJOR ELEMENT OF GRANITOID OF NATUNA, SINGKEP, BANGKA AND SIBOLGA." BULLETIN OF THE MARINE GEOLOGY 30, no. 1 (February 15, 2016): 45. http://dx.doi.org/10.32693/bomg.30.1.2015.74.
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A study of geochemical characteristic of major elelemnt of granitoid in Western Indonesia Region was carried out at Natuna, Bangka, Singkep and Sibolga. The SiO2 contents of the granites are 71.16 to 73.02 wt%, 71.77 to 75.56wt% and 71.16 to 73.02wt% at Natuna, Bangka, and Singkep respectively, which are classified as acid magma. While in Sibolga the SiO2 content from 60.27 to 71.44wt%, which is classified as intermediate to acid magma. Based on Harker Diagram, the granites from Natuna, Bangka and Singkep as a co-genetic. In other hand the Sibolga Granite show as a scatter pattern. Granites of Natuna, Bangka and Singkep have the alkaline-total (Na2O + K2O) between 6.03 to 8.51 wt% which are classified as granite and alkali granite regime. K2O content ranges from 3.49 to 5.34 wt% and can be classified as calc-alkaline type. The content of alkaline-total of Sibolga granite between 8.12 to 11.81 wt% and classified as a regime of syenite and granite. The range of K2O is about 5.36 to 6.94wt%, and assumed derived from high-K magma to ultra-potassic types. Granites of Natuna, Bangka and Singkep derived from the plutonic rock types and calc-alkaline magma, while Sibolga granite magma derived from K-high to ultra-potassic as a granite of islands arc. Based on the chemical composition of granite in Western Indonesian Region can be divided into two groups, namely Sibolga granite group is representing the Sumatera Island influenced by tectonic arc system of Sumatera Island. Granites of Bangka and Singkep are representing a granite belt in Western Indonesian Region waters which is influenced by tectonic of back arc.Keywords: magma, geochemical characteristic, major element and Western Indonesian Region Kajian karakteristik geokimia dari unsur utama granitoid di Kawasan Barat Indonesia telah dilakukan di daerah Natuna, Bangka, Singkep dan Sibolga. Kandungan SiO2 granit Natuna antara 71,16 - 73,02%, Bangka antara 71,77 - 75,56%, Singkep antara 72,68 - 76,81% termasuk dalam magma asam. Granit Sibolga memiliki kandungan SiO2 antara 60,27 - 71,44% termasuk dalam magma menengah - asam. Berdasarkan Diagram Harker, granit Natuna, Bangka dan Singkep mempunyai asal kejadian yang sama (ko-genetik), sedangkan granit Sibolga membentuk pola pencar. Granit Natuna, Bangka dan Singkep mengandung total alkalin (K2O+Na2O) antara 6,03 - 8,51% termasuk dalam jenis rejim granit dan alkali granit. Berdasarkan kandungan K2O antara 3,49 - 5,34 %berat, bersifat kalk-alkali. Granit Sibolga mengandung total alkali antara 8,12 - 11,81% termasuk dalam rejim syenit dan granit, dan berdasarkan kandungan K2O antara 5,36 - 6,94% berasal dari jenis magma K-tinggi sampai ultra-potassik. Granit Natuna, Bangka dan Singkep berasal dari jenis batuan beku dalam dan magma kalk-alkalin yang berhubungan dengan penunjaman, sedangkan granit Sibolga berasal dari jenis magma K-tinggi - ultra-potassik sebagai granit busur kepulauan. Berdasarkan komposisi unsur kimia utama, granit di Kawasan Barat Indonesia dapat dibagi dalam dua, yaitu granit Sibolga yang mewakili P. Sumatera, dipengaruhi oleh sistem tektonik busur P. Sumatera. Granit Bangka dan Singkep dapat mewakili suatu jalur granit di perairan Kawasan Barat Indonesia yang dipengaruhi oleh tektonik busur belakang. Kata kunci: jenis magma, karakteristik geokimia, unsur utama, dan Kawasan Barat Indonesia
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Mustafa, Moch Akrom, and Ediar Usman. "ANALISIS PERBANDINGAN GEOKIMIA GRANIT DAN SEDIMEN DASAR LAUT DI PULAU SINGKEP BAGIAN TIMUR, PROVINSI KEPULAUAN RIAU." JURNAL GEOLOGI KELAUTAN 11, no. 3 (February 16, 2016): 131. http://dx.doi.org/10.32693/jgk.11.3.2013.237.
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Hasil analisis kimia secara umum menunjukkan kesamaan antara granit dan sedimen permukaan dasar laut. Perbedaan hanya pada dua unsur, yaitu Al2O3 dan Fe2O3; kandungan Al2O3 pada granit antara 12,63 - 15,58% dan Fe2O3 antara 1,26 - 1,78%, sedangkan sedimen permukaan dasar laut Al2O3 berkisar antara 2,10 - 3,29% dan Fe2O3 antara 7,57 - 12,88%. Hasil analisis pada Diagram Harker menunjukkan penyebaran granit dan sedimen dasar laut membentuk pola searah, mengiindikasikan pola ko-magmatik.
Selanjutnya, untuk menentukan tipe granit di P. Singkep dalam kaitannya dengan kandungan timah, dua diagram SiO2 vs FeOtot/MgO dan ACF telah digunakan. Hasilnya menunjukkan bahwa granit Singkep termasuk daerah transisi antara tipe A dan tipe I&S dan tipe S yang kaya ilmenit dan berassosiasi dengan konsentrat timah.
Kata kunci: granit, sedimen dasar laut, kimia, tipe I&S, tipe S, timah, Pulau Singkep
Results of chemical analyses generally show the similarities between the granites and the seafloor sediments. The difference is only in the two elements, namely Al2O3 and Fe2O3; Al2O3 contents. In the granite ranges between 12.63 to 15.58% and the Fe2O3 ranges between 1.26 to 1.78%; while the seafloor sediment shows Al2O3 between 2.10 to 3, 29% and Fe2O3 between 7.57 to 12.88%. Results of the analysis on the Harker Diagram shows the distribution of the granites and the seafloors sediments form the unidirectional pattern, indicates the co-magmatic pattern.
Furthermore, to determine the type of granite in Singkep Island in relation with the tin content two diagram of SiO2 vs FeOtot/MgO and ACF are used. The result shows that the Singkep granite belong to the the transition area between the A and I&S and the S type which rich of ilmenite and associated with tin concentrate.
Keywords: granite, sea floor sediments, chemicals, I&S type, S type, tin, Singkep Island
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FEELY, MARTIN, DAVID SELBY, JON HUNT, and JAMES CONLIFFE. "Long-lived granite-related molybdenite mineralization at Connemara, western Irish Caledonides." Geological Magazine 147, no. 6 (April 22, 2010): 886–94. http://dx.doi.org/10.1017/s0016756810000324.
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AbstractNew Re–Os age determinations from the Galway Granite (samples: KMG = 402.2 ± 1.1 Ma, LLG = 399.5 ± 1.7 Ma and GBM = 383.3 ± 1.1 Ma) show that in south Connemara, late Caledonian granite-related molybdenite mineralization extended from c. 423 Ma to c. 380 Ma. These events overlap and are in excellent agreement with the published granite emplacement history determined by U–Pb zircon geochronology. The spatial distribution of the late-Caledonian Connemara granites indicates that initial emplacement and molybdenite mineralization occurred at c. 420 Ma (that is, the Omey Granite and probably the Inish, Leterfrack and Roundstone granites) to the N and NW of the Skird Rocks Fault, an extension of the orogen-parallel Southern Uplands Fault in western Ireland. A generally southern and eastward progression of granite emplacement (and molybdenite mineralization) sited along the Skird Rocks Fault then followed, at c. 410 Ma (Roundstone Murvey and Carna granites), at c. 400 Ma (Errisbeg Townland Granite, Megacrystic Granite, Mingling Mixing Zone Granodiorite, Lough Lurgan Granite and Kilkieran Murvey Granite) and at c. 380 Ma (Costelloe Murvey Granite, Shannapheasteen and Knock granites). The duration of granite magmatism and mineralization in Connemara is similar to other sectors of the Appalachian–Caledonian orogeny and several tectonic processes (e.g. slab-breakoff, asthenospheric flow, transtension and decompression) may account for the duration and variety of granite magmatism of the western Irish Caledonides.
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Fu, Jiangang, Guangming Li, Genhou Wang, Weikang Guo, Suiliang Dong, Yingxu Li, Hai Zhang, Wei Liang, and Yanjie Jiao. "Geochemical Evidence for Genesis of Nb–Ta–Be Rare Metal Mineralization in Highly Fractionated Leucogranites at the Lalong Dome, Tethyan Himalaya, China." Minerals 13, no. 11 (November 19, 2023): 1456. http://dx.doi.org/10.3390/min13111456.
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Leucogranites in the Lalong Dome are composed of two-mica granite, muscovite granite, albite granite, and pegmatite from core to rim. Albite granite-type Be–Nb–Ta rare metal ore bodies are hosted by albite granite and pegmatite. Based on field and petrographic observations and whole-rock geochemical data, highly differentiated leucogranites have been identified in the Lalong Dome. Two-mica granites, albite granites, and pegmatites yielded monazite ages of 23.6 Ma, 21.9 Ma, and 20.6 Ma, respectively. The timing of rare metal mineralization is 20.9 Ma using U–Pb columbite dating. Leucogranites have the following characteristics: high SiO2 content (>73 wt.%); peraluminosity with high Al2O3 content (13.6–15.2 wt.%) and A/CNK (mostly > 1.1); low TiO2, CaO, and MgO content; enrichment of Rb, Th, and U; depletion of Ba, Nb, Zr, Sr, and Ti; strong negative Eu anomalies; low εNd(t) values ranging from −12.7 to −9.77. These features show that the leucogranites are crust-derived high-potassium calc-alkaline and peraluminous S-type granites derived from muscovite dehydration melting under the water-absent condition, which possibly resulted from structural decompression responding to the activity of the South Tibetan detachment system (STDS). Geochemical data imply a continuous magma fractional crystallization process from two-mica granites through muscovite granites to albite granites and pegmatites. The differentiation index (Di) gradually strengthens from two-mica granite, muscovite granite, and albite granite to pegmatite, in which albite granite and pegmatite are highest (Di = 94). The Nb/Ta and Zr/Hf ratios of albite granite and pegmatite were less than 5 and 18, respectively, which suggests that albite granite and pegmatite belong to rare metal granites and have excellent potential for rare metal mineralization.
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Wilson, Reginald A., and Sandra L. Kamo. "Geochronology and lithogeochemistry of granitoid rocks from the central part of the Central plutonic belt, New Brunswick, Canada: implications for Sn-W-Mo exploration." Atlantic Geology 52 (April 29, 2016): 125. http://dx.doi.org/10.4138/atlgeol.2016.007.
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The central part of the Central plutonic belt in New Brunswick is underlain by numerous plutons of calc-alkaline, foliated and unfoliated granite that intrude Cambrian to Early Ordovician metasedimentary rocks. U-Pb (zircon) dating demonstrates that granites range in age from Middle Ordovician to Late Devonian, although most are late Silurian to Early Devonian. An age of 467 ± 7 Ma has been obtained on the foliated McKiel Lake Granite, whereas unfoliated intrusions yield ages of 423.2 ± 3.2 Ma (Bogan Brook Granodiorite), 420.7 +1.8/-2.0 Ma (Nashwaak Granite), 419.0 ± 0.5 Ma (Redstone Mountain Granite), 416.1 ± 0.5 Ma (Beadle Mountain Granite), 415.8 ± 0.3 Ma (Juniper Barren Granite), 409.7 ± 0.5 Ma (Lost Lake Granite), and 380.6 ± 0.3 Ma (Burnthill Granite). All plutons exhibit mixed arc-like and within-plate geochemical signatures, although the Redstone Mountain and Burnthill granites are dominantly of within-plate type. Trace element data reveal a close overall geochemical similarity between Ordovician and Silurian – Devonian plutons, indicating that all were generated by partial melting of the same crustal source. Late Silurian to Early Devonian plutons mainly comprise biotite and/or muscovite-bearing, peraluminous granite and are considered prospective for granophile-element mineralization. All plutons contain Sn well in excess of the granite global average abundance, and several contain average tin values comparable to productive stanniferous granites elsewhere. The Burnthill, Lost Lake, Beadle Mountain, and Nashwaak granites are geochemically most evolved and enriched in Sn and W. The Burnthill Granite in particular has experienced late-stage hydrothermal processes that have resulted in local enrichments of these elements.
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Vonopartis, Leonidas, Paul Nex, Judith Kinnaird, and Laurence Robb. "Evaluating the Changes from Endogranitic Magmatic to Magmatic-Hydrothermal Mineralization: The Zaaiplaats Tin Granites, Bushveld Igneous Complex, South Africa." Minerals 10, no. 4 (April 23, 2020): 379. http://dx.doi.org/10.3390/min10040379.
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The stanniferous granites of the Zaaiplaats Tin Field are part of the A-Type Lebowa Granite Suite, within the greater Bushveld Igneous Complex of northeast South Africa. The tin field comprises three granites: (1) the Nebo, a leucocratic, equigranular biotite granite; (2) The brick-red hypidiomorphic Bobbejaankop granite, which is extensively microclinized with chloritized biotite and characteristic synneusis-textured quartz; and (3) The variably altered roof facies of the Bobbejaankop granite known as the Lease microgranite. The Bobbejaankop and Lease granites were both extensively mined for cassiterite until 1989. The cassiterite is hosted in disseminations, miarolitic cavities, and within large hydrothermal, tourmalinized, and greisenized pipes and lenticular ore-bodies. An extensive petrological and whole-rock XRF and ICP-MS geochemical study, has provided new insight into the magmatic and magmatic-hydrothermal mineralization processes in these granites. Trace elements and Rayleigh Fractionation modelling suggest the sequential fractionation of the Nebo granite magma to be the origin of the Bobbejaankop granite. Incompatible elemental ratios, such as Zr/Hf and Nb/Ta, record the influence of internally derived, F-rich, hydrothermal fluid accumulation within the roof of the Bobbejaankop granite. Thus, the Lease granite resulted from alteration of the partially crystallized Bobbejaankop granite, subsequent to fluid saturation, and the accumulation of a magmatic-hydrothermal, volatile-rich fluid in the granite cupola. The ratio of Nb/Ta, proved effective in distinguishing the magmatic and magmatic-hydrothermal transition within the Bobbejaankop granite. Elemental ratios reveal the differences between pre- and post-fluid saturation in the mineralizing regimes within the same pluton. Thus highlighting the effect that the location and degree of hydrothermal alteration have had on the distribution of endogranitic tin mineralization.
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Uchida, Etsuo, Takumi Yokokura, Sota Niki, and Takafumi Hirata. "Geochemical Characteristics and U–Pb Dating of Granites in the Western Granitoid Belt of Thailand." Geosciences 14, no. 5 (May 14, 2024): 135. http://dx.doi.org/10.3390/geosciences14050135.
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This paper presents the integration of magnetic susceptibility measurements and whole-rock geochemical compositional and Nd–Sr isotopic ratio analyses for granite samples collected from the Ranong, Lam Pi, Ban Lam Ru, and Phuket granite bodies in the Western Granitoid Belt of Thailand. In addition, U–Pb dating was performed on zircons extracted from the samples. All samples are proper granites based on their mineralogical and geochemical characteristics. Two samples collected from the Lam Pi granite body were classified as magnetite-series and I-type. The remaining granite samples were classified as ilmenite-series and S- or A-type. Furthermore, all granites were classified as syn-collision granites. Excluding the magnetite-series samples from the Lam Pi granite body, the other samples exhibit enrichment in incompatible elements, such as Nb, Sn, Ta, Pb, Bi, Th, U, Ce, Rb, and Cs. Zircon U–Pb dating yielded ages of ca. 60 Ma for the magnetite-series granites from the Lam Pi granite body, whereas ages of 88–84 Ma were obtained for the other granite bodies. Initial Nd–Sr isotopic ratios indicate a higher contribution of mantle material in the Lam Pi magnetite-series granites and a higher contribution of continental crust material in the other granites. Based on these compositional and zircon U–Pb age data, it is inferred that the 88–84 Ma granites formed as a result of the thickening of the continental crust owing to the collision between the Sibumasu and the West Burma blocks. In contrast, the ca. 60 Ma Lam Pi magnetite-series granites are thought to have been generated via partial melting of the mantle wedge associated with the subduction of the Neo-Tethyan oceanic crust beneath the West Burma Block.
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Debowski, Beatriz Pereira, Guilherme Loriato Potratz, Armando Dias Tavares Júnior, Maria Virgínia Alves Martins, and Mauro Cesar Geraldes. "Age and Origin of the Massangana Intrusive Suite and Associated Mineralizations, in the Rondônia Tin Province: Petrography, U-Pb, and Lu-Hf Isotopes Zircons." Minerals 12, no. 10 (October 16, 2022): 1304. http://dx.doi.org/10.3390/min12101304.
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Rondônia intrusive suites represent the youngest A-type magmatism that occurred in the SW of the Amazon craton, with mineralizations in Sn, Nb, Ta, W, and topaz. Petrological and isotopic studies (U-Pb and Lu-Hf by LA-ICP-MS) allowed the Massangana granite to be subdivided into São Domingos facies (medium to fine biotite-granite), Bom Jardim facies (fine granite), Massangana facies (pyterlites and coarse granites) and Taboca facies (fine granites). The crystallization ages obtained were between 995.7 ± 9.5 Ma to 1026 ± 16 Ma, and the εHf values vary significantly between positive and negative, showing predominantly crustal sources for forming these rocks. Petrographic studies on ore samples indicate the action of co-magmatic hydrothermal fluids enriched in CO2, H2O, and F. These ores are characterized by endogreisens, exogreisens, pegmatites, and quartz veins that are explored in the São Domingos facies area. The endogreisens and exogreisens are formed by topaz-granites and zinnwaldite-granites; the pegmatites are formed by topaz-zinnwaldite-cassiterite-granites; and the veins by cassiterite-sulfides and quartz. The geometries of the mineralized bodies indicate a dome-shaped contact with the host rocks in the magma chamber and can be attributed to residual accumulation. In this sense, the origin of these ores is related to the evolution of intrusive granitic bodies where the terminal phases of the fluid-enriched magma are lodged in the apical portions, and the origin of the mineralized bodies present a biotite-granite, albite-granite, and endogreisens evolution (potassium series), or biotite-granite, alkali-granite and endogreisens (sodic series) and these rocks present TDM ages that indicate a concerning relation to the non-mineralized rocks of Massangana granite.
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Šuica, Sanja, Vesnica Garašić, and Alan B. Woodland. "Petrography and geochemistry of granitoids and related rocks from the pre-Neogene basement of the Slavonia-Srijem Depression (Croatia)." Geologia Croatica 75, no. 1 (February 28, 2022): 129–44. http://dx.doi.org/10.4154/gc.2022.09.
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The pre-Neogene basement of the Slavonia-Srijem Depression (eastern Croatia) is composed of various types of igneous, metamorphic and sedimentary rocks. Here we present the petrography and geochemistry of a heterogenous group represented by two types of alkali granite, granite, syenite, rhyolite and orthogneiss. The alkali granite type 1 has an A-type geochemical affinity: a ferroan character, high alkali content, high concentration of rare earth elements (REE3+), Rb, Zr, Nb and Y, and low CaO, MgO, P2O5, Ba, Sr and Eu contents. The syenite has similar characteristics, but displays enrichment in Ba, K, Eu and Zr, which could be a consequence of feldspar and zircon accumulation. The alkali granite type 2 is an A-type granite but differs from the alkali granite type 1 in having lower K2O and Rb, accompanied by higher Na2O and Sr concentrations, possibly resulting from alteration or a different parental magma/evolutionary process. The granite and rhyolite are distinguished from both types of alkali granite by their magnesian character, lower Zr, Nb and Y concentrations, less pronounced Eu negative anomaly, as well as higher Ba, Sr and LREE/HREE. The orthogneiss displays differences in major element chemistry compared to the alkali granite type 1, but has similar trace element and REE patterns. The alkali granites are characterized by Y/Nb<1.2, indicating an ocean island basalt-like source, while the granite originated from melting of a crustal, probably metasedimentary source. The A-type granites could belong to the Late Cretaceous A-type magmatism of the Sava Zone, while the granite is significantly different from the Sava Zone A-type granites as well as the other rocks investigated in this study.
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Nguyen, Tai Minh, Hoa Xuan Tran, Giang Thi Truong Nguyen, Cuong Chi Truong, and Minh Pham. "U-Pb zircon and Hf composition of granite Song Ma block." Science and Technology Development Journal - Natural Sciences 2, no. 4 (August 14, 2019): 167–75. http://dx.doi.org/10.32508/stdjns.v2i4.825.
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The granite of the Song Ma block mainly consists of two types of granite: biotite granite and hornblende-biotite granite. Biotite granites have the percent of plagioclase (35– 45%), K-feldspar (25–35%), quartz (~20%) and biotite (~10%). Biotite-hornblende granite with the content of plagioclase (40–50%), Kfeldspar (10–15%), hornblende (5–10%) and biotite (5%). Zircon crystals were selected from the granite of Song Ma block are V0741, V0856 and V1006 samples with the LA-ICPMS U-Pb analyses gave concordant ages concentrated at 257±4Ma, 262±3Ma and 241±6Ma (weighted mean). Those ages are older than the results of the previous research. The mineral assemblages and geochemical characteristics show the typical of I-type granites. The results of Hf isotope composition analysis give the value of εHf(t) from +7.3 to +13.9, which is proven the sources of the granite Song Ma block similar to the granite of Phan Si Pan zone, NW Viet Nam during the period from late Permian to early Triassic.
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Brooks, Kent. "Granites." Geology Today 39, no. 5 (September 2023): 196–202. http://dx.doi.org/10.1111/gto.12450.
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Granites are coarse‐grained igneous intrusive rocks, which, although present in most tectonic settings, are most characteristic of continental crust. While basalts are the most abundant volcanic rocks, granites are the most abundant intrusive rocks. On the scale of the Solar System, while basalts are ubiquitous, granites seem to be restricted to the Earth. The volcanic equivalent of granite is rhyolite, although rhyolites are of much lower abundance than granite, probably because such magmas are more viscous and less likely to reach the surface. In addition, many pyroclastic rocks have a granitic composition and are likely to have their origins in underlying granitic plutons. Granites may originate by differentiation of a basaltic magma, but the abundance of granites and the low abundance of intermediate rocks argues in general against this possibility and granite magmas are generally thought to have formed by melting of pre‐existing rocks. Several distinct types of granite are recognized depending on their origin.
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Imeokparia, E. G. "Geochemical evolution of the Jarawa Younger Granite complex and its related mineralization, northern Nigeria." Geological Magazine 122, no. 2 (March 1985): 163–73. http://dx.doi.org/10.1017/s0016756800031071.
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AbstractThe Jarawa Younger Granite complex is composed of high silica alkali granites that were emplaced 161 Ma ago. The granites are characterized by high contents of Rb, Li, F, Sn, Nb, W above normal low-Ca granitic rocks and have typical S-type characteristics that are indicative of a substantial component of crustal melt.Mineralization in the complex is associated with the biotite granite which was emplaced as a sheet-like body at relatively shallow depth and occurs as disseminations and as greisen lodes and veins.Chemical studies of the granites have shown that the biotite granite represents a highly fractionated rock that crystallized from a residual magma from which the hornblende-biotite granite had previously crystallized. However the biotite granite is characterized by steep gradients in some minor and trace elements that apparently indicate that liquid-state differentiation and/or volatile complexing processes made significant contributions to their differentiation. Enrichment of Th, Li, Rb, Sn, W and Nb may be more closely linked to roofward migration of F.
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Mishra, Sumit, Vinod K. Singh, Alexander I. Slabunov, H. C. Nainwal, Pradip K. Singh, Neeraj Chaudhary, and D. C. Nainwal. "Geochemistry and geodynamic setting of Paleoproterozoic granites of Lesser Garhwal Himalaya, India." Journal of Geoscience, Engineering, Environment, and Technology 4, no. 2-2 (July 25, 2019): 28. http://dx.doi.org/10.25299/jgeet.2019.4.2-2.2138.
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The granite and gneisses rocks are well exposed around Toneta, Tilwara and Chirbatiyakhal region in the Lesser Garhwal Himalaya have less studied which consider as Paleoproterozoic age. The granites from Toneta area are classified as K-rich peraluminous granite with low Na2O varies from 0.85 to 2.4 wt.% and high K2O content varies from 5.0 to 6.9 wt.%. The average Al2O3 (14.16 wt.%) in the granite is greater than the total alkalies (Na2O+K2O = Av. 7.62 wt.%), the Titania (TiO2) content is low ranging from 0.1 to 0.28 wt. %. In the Y + Nb – Rb, Y – Nb, Ta + Yb – Rb, and Yb – Ta discrimination diagram of Pearce et al. (1984) show that the Toneta granites mostly plots within the syn-collision granite fields. This is typical collisional granite.
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Broska, Igor, and Michal Kubiš. "Accessory minerals and evolution of tin-bearing S-type granites in the western segment of the Gemeric Unit (Western Carpathians)." Geologica Carpathica 69, no. 5 (October 1, 2018): 483–97. http://dx.doi.org/10.1515/geoca-2018-0028.
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Abstract The S-type accessory mineral assemblage of zircon, monazite-(Ce), fluorapatite and tourmaline in the cupolas of Permian granites of the Gemeric Unit underwent compositional changes and increased variability and volume due to intensive volatile flux. The extended S-type accessory mineral assemblage in the apical parts of the granite resulted in the formation of rare-metal granites from in-situ differentiation and includes abundant tourmaline, zircon, fluorapatite, monazite-(Ce), Nb–Ta–W minerals (Nb–Ta rutile, ferrocolumbite, manganocolumbite, ixiolite, Nb–Ta ferberite, hübnerite), cassiterite, topaz, molybdenite, arsenopyrite and aluminophosphates. The rare-metal granites from cupolas in the western segment of the Gemeric Unit represent the topaz–zinnwaldite granites, albitites and greisens. Zircon in these evolved rare-metal Li–F granite cupolas shows a larger xenotime-(Y) component and heterogeneous morphology compared to zircons from deeper porphyritic biotite granites. The zircon Zr/Hfwt ratio in deeper rooted porphyritic granite varies from 29 to 45, where in the differentiated upper granites an increase in Hf content results in a Zr/Hfwt ratio of 5. The cheralite component in monazite from porphyritic granites usually does not exceed 12 mol. %, however, highly evolved upper rare-metal granites have monazites with 14 to 20 mol. % and sometimes > 40 mol. % of cheralite. In granite cupolas, pure secondary fluorapatite is generated by exsolution of P from P-rich alkali feldspar and high P and F contents may stabilize aluminophosphates. The biotite granites contain scattered schorlitic tourmaline, while textural late-magmatic tourmaline is more alkali deficient with lower Ca content. The differentiated granites contain also nodular and dendritic tourmaline aggregations. The product of crystallization of volatile-enriched granite cupolas are not only variable in their accessory mineral assemblage that captures high field strength elements, but also in numerous veins in country rocks that often contain cassiterite and tourmaline. Volatile flux is documented by the tetrad effect via patterns of chondrite normalized REEs (T1,3 value 1.46). In situ differentiation and tectonic activity caused multiple intrusive events of fluid-rich magmas rich in incompatible elements, resulting in the formation of rare-metal phases in granite roofs. The emplacement of volatile-enriched magmas into upper crustal conditions was followed by deeper rooted porphyritic magma portion undergoing second boiling and re-melting to form porphyritic granite or granite-porphyry during its ascent.
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Grantham, G. H., A. B. Moyes, and D. R. Hunter. "The age, petrogenesis and emplacement of the Dalmatian Granite, H.U. Sverdrupfjella, Dronning Maud Land, Antarctica." Antarctic Science 3, no. 2 (June 1991): 197–204. http://dx.doi.org/10.1017/s0954102091000238.
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The ∼470 Ma Dalmatian Granite forms sheet-like bodies intruded discordantly into orthogneisses, paragneisses and calcareous rocks belonging to the ∼1000 Ma Jutulrora, Sveabreen and Fuglefjellet formations respectively. The Dalmatian Granite is muscovite + biotite bearing. Two varieties are recognized, one that is magnetite-bearing and another that is characterized by tourmaline nodules. At some localities, development of the tourmaline-bearing variety is spatially associated with the presence of carbonates. Physical conditions of emplacement for the Dalmatian Granite are estimated to be approximately 700°C and 6kbar with pH2O = Pload. The emplacement of the granite is considered to have occurred syntectonically during D3 approximately 470 Ma ago. The granites are therefore similar in age to Pan African age granites in Mozambique as well as Ross Orogeny age granites in the Transantarctic Mountains.
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Stone, Maurice. "The Tregonning granite: petrogenesis of Li-mica granites in the Cornubian batholith." Mineralogical Magazine 56, no. 383 (June 1992): 141–55. http://dx.doi.org/10.1180/minmag.1992.056.383.01.
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AbstractLi-mica (zinnwaldite and/or lepidolite)—topaz—albite granites in the Tregonning—Godolphin pluton and similar rocks in the St. Austell pluton appear to be petrogenetically unrelated to the spatially associated biotite granites. Evidence is provided by lack of development of Li-mica granites at roof zones of biotite granites and markedly different trends and composition fields in bivariate plots such as Li vs. Cs, Rb vs. Sr and Nb vs. Zr. Thus, differentiation of biotite granite magma is unlikely to have generated Li-mica granite magma, as also, on its own, is partial melting of biotite granite or biotiteabsent residual lower crust. However, partial melting of biotite-rich residual rocks involving biotite breakdown could yield a trace alkali- and F-enriched melt, although this would require marked femic mineral, K-feldspar and anorthite fractionation, and Na-enrichment. It is proposed that volatiles derwed from either a mantle source or the crust/mantle interface have aided metasomatism of either residual S-type crust that earlier provided S-type biotite granite magma, or basic (biotite-rich) granitoid, to produce a low-temperature, low-viscosity Li-mica granite melt that rose rapidly in the crust soon after the emplacement of associated biotite granites.
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Friend, C. R. L., M. Brown, W. T. Perkins, and A. D. M. Burwell. "The geology of the Qôrqut granite complex north of Qôrqut, Godthåbsfjord, southern West Greenland." Bulletin Grønlands Geologiske Undersøgelse 151 (January 1, 1985): 1–43. http://dx.doi.org/10.34194/bullggu.v151.6693.
Full textAbstract:
The late Archaean (c. 2550 Ma) Qôrqut granite complex post-dates the major part of the geological evolution of the Godthåbsfjord region of southern West Greenland. The complex is composed of a variety of granites intruded as a multitude of individual sheets. The granites are divided into three groups according to their age relations and overall characteristics: leucocratic granites, grey biotite granites, and composite granites. Moreover, the complex can be divided into three zones: upper, intermediate and lower. These zones have different proportions of the three granite groups and included country rocks. Textures and structures typical of partial melting are found in highly modified gneiss enclaves contained in the leucocratic granites of the lower zone. All stages of the transition from gneiss to granite are present. Field evidence suggests that much of the biotite contained in the granites may be derived from the parent gneiss. Petrographic and mineral data are presented to support this contention. In some parts of the complex in the area studied extensive mineral and lithological layering is present. This most commonly occurs in the leucocratic granites and consists of biotite-rich versus biotite-poor granite. Otherwise seams and thin layers of biotite are found which, in part, may be derived from the partially melted enclaves. Lithological layering may also be produced by intrusive effects of thin sheets of granite of slightly different characteristics. Using mesonormative components the granites approximate to minimum melts in the granite system and appear to have crystallised under conditions where PTotal was less than 5 kbar. The melting zone for the leucocratic granites was not far below the present level of exposure. The grey biotite granites were probably derived from slightly deeper levels. The tectonic regime under which the Archaean crust was partially melted allowed small, discrete batches of magma rapid access to higher levels of the crust. Once at this higher level, emplacement was constrained to a sheet form. The complex was thus built up by successive intrusions of small batches of magma.
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He, Zhilei, Zhende Zhu, Nan Wu, Zhen Wang, and Shi Cheng. "Study on Time-Dependent Behavior of Granite and the Creep Model Based on Fractional Derivative Approach Considering Temperature." Mathematical Problems in Engineering 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/8572040.
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Based on mineral components and the creep experimental studies of Three Gorges granite and Beishan granite from different regions of China at various temperatures, the strength and creep property of two types of granites are compared and analyzed. Considering the damage evolution process, a new creep constitutive model is proposed to describe the creep property of granite at different temperatures based on fractional derivative. The parameters of the new creep model are determined on the basis of the experimental results of the two granites. In addition, a sensitivity study is carried out, showing effects of stress level, fractional derivative order, and the exponentm. The results indicate that the proposed creep model can describe the three creep stages of granite at different temperatures and contribute to further research on the creep property of granite.
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Hayatu, Raliya Aminu. "GEOCHEMISTRY AND GENETIC IMPLICATIONS OF BASEMENT ROCKS AROUND MAKARFI AREA, NORTHWESTERN NIGERIA BASEMENT COMPLEX." FUDMA JOURNAL OF SCIENCES 8, no. 3 (June 30, 2024): 319–30. http://dx.doi.org/10.33003/fjs-2024-0803-2552.
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Major and trace element analysis of rocks around Makarfi were carried out using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to determine the geochemical characteristics of the lithological components of the area. The area is composed of migmatite gneiss, biotite gneiss, granite gneiss, schists and granites. Analysis for major, trace and REE revealed that the gneisses, are paragneisses and metaluminous. The granites are peraluminous (A/CNK>1) and calc-alkaline. The granites had undergone changes from a more primitive hornblende-biotite I-type variety to a more fractionated muscovite bearing S-type variety. Chemical data shows that the peraluminosity and enrichment in Li, Rb, Cs, Ta, Sn, Nb and Ga increases in the course of differentiation and evolution from hornblende-biotite granite to muscovite granite. Signatures of biotite and muscovite granites suggest emplacement in a syn-collisional tectonic setting while those of hornblende-biotite granite suggest a post-collisional tectonic setting.
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Konyshev, A. A., Ya O. Alferyeva, M. O. Anosova, A. A. Rusak, and Y. I. Korepanov. "Mica composition of Salmi batholith granites as an indicator of forming Nb-Ta mineralization." Moscow University Bulletin. Series 4. Geology, no. 3 (June 28, 2019): 69–77. http://dx.doi.org/10.33623/0579-9406-2019-3-69-77.
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The Salmi batholith’s successive felsic rocks differentiates are represented by a series: biotite-amphibole granite-rapakivi, biotite granite, highly differentiated granites (Li-siderophyllite granite and zinnwaldite Li-F granite). In this series of rocks a gradual increase in content of Ta and Nb and a decrease in the Nb/Ta ratio is seen. A regular change in the separation factors of Ta and Nb between mica and the total composition of the rock is observed as well. When comparing Li-siderophyllite granites and Li-F granites, the latter have a sharp decrease in the separation coefficients KrTa, Nb. This decrease is due to the fall in content of these metals in Li-F granites zinnwaldite and associated with the appearance of columbite in these rocks. The study of rock samples from the Salmi batholith suggests that the change of the Ta and Nb content in the mica of deeply differentiated granites and the corresponding decrease in the Kr value of these metals may be a diagnostic indication of the presence of columbite mineralization in the rock.
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Pidgeon, R. T., and W. Compston. "A SHRIMP ion microprobe study of inherited and magmatic zircons from four Scottish Caledonian granites." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 83, no. 1-2 (1992): 473–83. http://dx.doi.org/10.1017/s0263593300008142.
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ABSTRACTUsing the ion microprobe SHRIMP we have analysed zircons from the Ben Vuirich, Glen Kyllachy, Inchbae and Vagastie Bridge granites from the Scottish Caledonides, in an attempt to resolve the ages of inherited zircons shown to be present in these granites by previous conventional multigrain analyses. Middle Proterozoic age components were found in inherited zircons from all four granites. Late Proterozoic (900–1,100 Ma) components have been identified in zircons from the Glen Kyllachy and Ben Vuirich granites in the Grampian Highlands. A Late Archaean age has only been detected in one zircon from the Glen Kyllachy granite. The distribution of inherited components in the granite zircon populations could reflect fundamental divisions in the age composition of granite source rocks; however, detailed assessment of this possibility must await further ion microprobe analyses on zircons from many more granites.SHRIMP isotopic and U, Th and Pb analyses were made on successive shells of zoned zircon surrounding inherited cores from the Glen Kyllachy granite to monitor chemical changes during magmatic zircon growth. Results show that zircon shells have characteristic but significantly different Th, U and Pb concentrations. Magmatic zircon from the Vagastie Bridge granite also forms as clearly defined oscillatory zoned shells around unzoned nuclei of inherited zircon. However, the distinction between magmatic and inherited zircon in zircons from the Inchbae granite is less clear. Zircons from the Ben Vuirich granite occur as euhedral, magmatic zircons, or as rounded, subhedral, inherited zircon grains. A SHRIMP age of 597 ± 11 (2σ) Ma for euhedral magmatic zircon from this granite is identical, within the uncertainty, to the conventional multigrain zircon age of 590 ± 2 (2σ) Ma reported by Rogers et al. (1989) and confirms the conclusions of those authors that sedimentation of the Dalradian sequence took place in the Precambrian.
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Sun, Zhenjun, Guanghu Liu, Yunsheng Ren, Xi Chen, Xinhao Sun, Chengyang Wang, and Zuowu Li. "Age, Genesis and Tectonic Setting of the Sayashk Tin Deposit in the East Junggar Region: Constraints from Lu–Hf Isotopes, Zircon U–Pb and Molybdenite Re–Os Dating." Minerals 12, no. 9 (August 23, 2022): 1063. http://dx.doi.org/10.3390/min12091063.
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The Sayashk tin (Sn) deposit is located within the southern part of the Eastern Junggar orogenic belt in Xinjiang Province and forms part of the Kalamaili alkaline granite belt. There are many Sn polymetallic deposits in the area. To constrain the age, genesis, and tectonic setting of the Sayashk tin deposit in the East Junggar region, we conducted a bulk-rock geochemical analysis of the granite porphyry (SR1) and medium- to fine-grained granite (SR2) hosts of the deposit, LA-ICP-MS zircon U–Pb dating and Lu–Hf isotopic analysis, as well as molybdenite Re–OS dating and combined our results with the metallogenic conditions and other geological characteristics of the deposit. The results show that the Sayashk Sn deposit is indeed spatially, temporally, and genetically closely related to the granite porphyry and medium-fine-grained granite. Both zircon U–Pb ages are 308.2 ± 1.5 Ma and 310.9 ± 1.5 Ma, respectively. The isochron age of molybdenite is 301.4 ± 6.7 Ma, which represents the crystallization age of the granite porphyry and medium-fine-grained granite. Therefore, all of them formed in the late Carboniferous epoch. The medium-fine-grained granites and granite porphyry are characteristically rich in Si and alkali, poor in Ca and Mg, rich in high field-strength elements (HFSE, e.g., Zr, Hf) and Ce, and deficient in Ba, Sr, Eu, P, and Ti. They are typical A-type granites, showing the characteristics of a mixed crustal mantle source. The εHf(t) values of the zircon from the granite porphyry (SR1) range from 10.27 to 16.17 (average 13.71), εHf(t) values of the zircon from the medium-fine-grained granites (SR2) are between 5.72 and 9.21 (average 7.08), and the single model ages (TDM1) and two-stage model ages (TDM2) of the granite porphyry (SR1) fall within the ranges of 319~535 Ma and 339~644 Ma. The single model ages (TDM1) and two-stage model ages (TDM2) of the medium-fine-grained granites (SR2) fall within the ranges of 346~479 Ma and 309~557 Ma. There is little difference between their two-stage model ages and zircon U–Pb ages, indicating that the Sayashk granite may be the product of partial melting of juvenile crustal. Combined with previous research results, the Sayashk Sn deposit formed in a post-collision extensional tectonic setting after the late Carboniferous in the Kalamaili area.
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Ngadenin, Ngadenin, and Adhika Junara Karunianto. "Identifikasi Keterdapatan Mineral Radioaktif pada Granit Muncung Sebagai Tahap Awal untuk Penilaian Prospek Uranium dan Thorium di Pulau Singkep." EKSPLORIUM 37, no. 2 (December 19, 2016): 63. http://dx.doi.org/10.17146/eksplorium.2016.37.2.3101.
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ABSTRAKPulau Singkep adalah bagian dari jalur timah Asia Tenggara, yang salah satu litologinya tersusun oleh granit Muncung. Keberadaan granit tersebut memungkinkan adanya cebakan mineral radioaktif yang prospek terhadap uranium dan thorium. Penelitian ini bertujuan untuk mengidentifikasi keterdapatan mineral radioaktif pada granit Muncung sebagai tahap awal untuk penilaian prospek uranium dan thorium di Pulau Singkep. Metoda yang digunakan adalah pengambilan sampel batuan granit, analisis petrografi sampel granit Muncung, analisis kadar uranium dan thorium serta analisis butir sampel konsentrat dulang yang diambil di wilayah granit Muncung. Mineral radioaktif pada granit Muncung adalah monasit dan zirkon sedangkan pada konsentrat dulang adalah monasit, zirkon, dan senotim. Persentase monasit dalam konsentrat dulang adalah 1,1 – 59,53 %, zirkon 0,68 –55,07 % dan senotim 0,39 – 3,54 %. Kadar uranium dalam konsentrat dulang adalah 30 – 1.346 ppm dan kadar thorium 557 – 13.200 ppm. Disimpulkan bahwa daerah di sekitar granit Muncung dianggap cukup prospek uranium dan thorium dan dapat dikembangkan ke tahapan eksplorasi lebih detail. ABSTRACTSingkep Island is part of Southeast Asia tin belt, which is one of the lithologies, composed of granite Muncung. Existence of granite allows formed deposits of radioactive minerals that prospect of the uranium and thorium. This research goal is to identify radioactive minerals occurrences on granit Muncung in the initial stage for prospect assessment of uranium and thorium in Singkep Island. The Methodologies are granite sampling, petrography analysis of Muncung granite samples, uranium and thorium content analysis and grain size analysis of pan concentrate samples. Radioactive minerals in Muncung granite are monazite and zircon, while in pan concentrate they are monazite, zircon, and xenotime. The percentage of monazite, zircon, and xenotime in the pan concentrate are 1.1–59.53 %, 0.68–55.07 %, and 0.3–3.54 % respectively. The uranium and thorium content in the pan concentrate are 30–1,346 ppm and 557–13,200 ppm respectively. It concluded that the area around the Muncung granite considered prospect for uranium and thorium, and possibly developed into more detailed exploration stage.
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Conliffe, J., and M. Feely. "Fluid inclusions in Irish granite quartz: monitors of fluids trapped in the onshore Irish Massif." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 101, no. 1 (December 20, 2010): 53–66. http://dx.doi.org/10.1017/s1755691010009047.
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ABSTRACTFluid inclusion studies of granite quartz provide an opportunity to study fluid flow associated with igneous activity and post-emplacement fluid processes. This study presents new fluid inclusion data from the late Caledonian Donegal granites and Newry granodiorite, and the Tertiary Mourne Mountains granite in Ireland, which identify three distinct fluids. Aqueous-carbonic fluids (Type 1) have been recorded in late Caledonian granites with a significant mantle component (Newry granodiorite and the Ardara and Thorr granites in Donegal). These fluids represent late-magmatic fluids trapped at high temperatures (up to 575°C), and the ultimate source of these carbonic fluids is linked to sub-lithospheric processes during the Caledonian orogeny. The dominant fluid type (Type 2) in late Caledonian granites is a H2O+NaCl±KCl fluid which may be related to thermal convection cells around granite bodies and/or to regional scale influx of surface derived fluids at the end of the Caledonian orogeny. High salinity NaCl–CaCl2 fluids (Type 3) overprint quartz in the Ardara granite in Donegal, and in the Newry granodiorite, and are interpreted to represent basinal brines, sourced in overlying sedimentary basins, which circulated through the crystalline basement during a period of crustal extension (possibly during the Carboniferous or the Triassic). Fluid inclusion studies of the Tertiary Mourne Mountains granites have identified only Type 2 fluids related to thermal convection cells, consistent with stable isotope evidence, which indicates that this younger granite is unaffected by regional-scale fluid influxes.
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STEPANYUK, L. M., S. I. KURYLO, O. V. KOVTUN, T. I. DOVBUSH, and O. B. VYSOTSKY. "Uranium-Lead Geochronology of Two-Feldspar Granites of the Inhul Megablock (Ukrainian Shield) by Monazite." Mineralogical journal 43, no. 2 (2021): 49–57. http://dx.doi.org/10.15407/mineraljournal.43.02.049.
Full textAbstract:
In the area of the Novooleksandrivka village, the valley of the Bokovenka river crosses a powerful strip of metamorphic rocks of the Inhulo-Inhulets series with numerous small granitoid bodies of the Kirovohrad complex. In the right bank of the river valley north of Novooleksandrivka there are almost continuous rock outcrops of porphyry-like, mostly coarse-grained garnet-biotite granites, which are cut by veins of aplite-pegmatoid and pegmatoid granites. Uranium-lead isotope systems of accessory monazites from porphyry-like granite, layered body of uneven-grained granite and from veined body of aplite-pegmatoid granite have been studied. The age of the first two, more coarse-grained granite varieties, is 2043.2 ± 2.6 and 2041 ± 2.3 million years, respectively. Significantly younger are the monocytes from the vein of aplite-pegmatoid granite - 2030 ± 0.3 million years. In granites in this sequence, in addition to structural and textural characteristics (in general, decrease in grain size), there is a decrease in the amount of SiO2 (from 73.14 to 70.93%) connected with a significant increase in K2O (from 3.96 to 7.58%), (their inverse correlation coefficient is 0.98), a significant decrease in the CaO content from 2.04 to 0.97%, and a slight decrease in the MgO content from 1.14% to 0.82%. These changes are probably caused by the crystallizational differentiation of the original granite melt.
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Estrade, Guillaume, Stefano Salvi, and Didier Béziat. "Crystallization and destabilization of eudialyte-group minerals in peralkaline granite and pegmatite: a case study from the Ambohimirahavavy complex, Madagascar." Mineralogical Magazine 82, no. 2 (February 28, 2018): 375–99. http://dx.doi.org/10.1180/minmag.2017.081.053.
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AbstractEudialyte-group minerals (EGM) are very common in highly evolved SiO2-undersaturated syenites and are characteristic minerals of agpaitic rocks. Conversely, they are extremely rare in peralkaline granites, with only a handful of EGM occurrences reported worldwide. Here, we study two new examples of EGM occurrence in two types of peralkaline pegmatitic granites from the Cenozoic Ambohimirahavavy complex, and assess the magmatic conditions required to crystallize EGM in peralkaline SiO2-oversaturated rocks. In the transitional granite (contains EGM as accessory minerals) EGM occur as late phases and are the only agpaitic and major rare-earth element (REE) bearing minerals. In the agpaitic granite (contains EGM as rock-forming minerals) EGM are early-magmatic phases occurring together with two other agpaitic minerals, nacareniobsite-(Ce) and turkestanite. In these granites, EGM are partly-to-completely altered and replaced by secondary assemblages consisting of zircon and quartz in the transitional granite and an unidentified Ca-Na zirconosilicate in the agpaitic granite. Ambohimirahavavy EGM, as well as those from other peralkaline granites and pegmatites, are richer in REE and poorer in Ca than EGM in nepheline syenites. We infer that magmatic EGM are rare in SiO2-oversaturated rocks because of low Cl concentrations in these melts. At Ambohimirahavavy, contamination of the parental magma of the agpaitic granite with Ca-rich material increased the solubility of Cl in the melt promoting EGM crystallization. In both granite types, EGM were destabilized by the late exsolution of a fluid and by interaction with an external Ca-bearing fluid.
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Syomka, V. O., L. M. Stepanyuk, O. M. Ponomarenko, S. M. Bondarenko, V. V. Sukach, S. I. Kurylo, and M. O. Donskyi. "MINERALOGICAL AND PETROLOGICAL CHARACTERISTICS OF GRANITES OF THE SHPOLA-TASHLYK ORE DISTRICT (THE UKRAINIAN SHIELD)." Mineralogical Journal 45, no. 4 (2023): 29–47. http://dx.doi.org/10.15407/mineraljournal.45.04.029.
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Mineralogical and petrographical research of different types of granites of the Kirovohrad complex, such as of Lypniazhka, Berezivske, Yaroshivka, Dorofiivka, Hlodosy, in the Shpola-Tashlyk ore district of the Ukrainian Shield, has been conducted. It allows to identify them as rare-metal genetic type. The evidence comes from: High silica (SiO2 = 71.70—74.24%), agpaitic index (0.53—0.71) and low iron oxidation (0.16—0.59) in granites. Furthermore, they are enriched with fluorine and boron based on occurrence of accessory fluorite and tourmaline. Characteristic chemical feature of the granites is a prevalence of potassium over sodium. The contents of phosphorus, zirconium, cerium, lanthanum, and lithium in Berezivske granites exceed average contents for such elements of the Ukrainian Shield, due to accessory mineralization — apatite, monazite, and lithium-bearing mica. The most high lithium grades (55 ppm) are specific for Lypniazhka and Yaroshivka granites where at their exocontact zone the lithium deposits and occurrences of niobium, tantalum, and stannum were discovered. Based on structure and texture features, massive, porphyroblastic, gneiss-like, and aplite-pegmatoid types with gradual transitions were distinguished; it is an evidence of their genetic relation. It was defined that Lypniashka granites related to the lithium pegmatite deposit have mineralogical features comparing to other types of granites, such as: a) highest ВаО (0.44—0.53 %) content in microclines; b) most ferrous biotite (f = 0.64 %) with the highest content of fluorine (0.16 %). Isotopic and geochemical research of monazite was conducted. The granites age ranges from 2026 to 2042 Ma. The granites related to rare-metal mineralization yielded ages from 2026 to 2037 Ma comparing to the oreless granites (Smoline urban-type settlement) with age 2042 Ma. On biotite-garnet geothermometer study the granites’ formation temperatures were defined, such as: Dorofiivka granite — 625°С, Berezivske granite — 640ºС, Hlodosy granite — 640ºС, and Yaroshivka granite (Т = 640—750ºС, Р = 500—700 MPa). Considering field observations and facts mentioned above the Berezivske granites belong to rare-metal granite complex of S-type.
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Mohammadi, Nadia, Les Fyffe, Christopher R. M. McFarlane, Kay G. Thorne, David R. Lentz, Brittany Charnley, Laurin Branscombe, and Sheena Butler. "Geological relationships and laser ablation ICP-MS U-Pb geochronology of the Saint George Batholith, southwestern New Brunswick, Canada: implications for its tectonomagmatic evolution." Atlantic Geology 53 (May 6, 2017): 207–40. http://dx.doi.org/10.4138/atlgeol.2017.008.
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The Late Silurian to Late Devonian Saint George Batholith in southwestern New Brunswick is a large composite intrusion (2000 km2) emplaced into the continental margin of the peri-Gondwanan microcontinent of Ganderia. The batholith includes: (1) Bocabec Gabbro; (2) equigranular Utopia and Wellington Lake biotite granites; (3) Welsford, Jake Lee Mountain, and Parks Brook peralkaline granites; (4) two-mica John Lee Brook Granite; (6) Jimmy Hill and Magaguadavic megacrystic granites; and (6) rapakivi Mount Douglas Granite. New LA ICP-MS in situ analyses of six samples from the Saint George Batholith are as follows: (1) U-Pb monazite crystallization age of 425.5 ± 2.1 Ma for the Utopia Granite in the western part of the batholith (2) U-Pb zircon crystallization ages of 420.4 ± 2.4 Ma and 420.0 ± 3.5 Ma for two samples of the Utopia Granite from the central part of the batholith; (3) U-Pb zircon crystallization age of 418.0 ± 2.3 Ma for the Jake Lee Mountain Granite; (4) U-Pb zircon crystallization age of 415.5 ± 2.1 Ma for the Wellington Lake Granite; and (5) U-Pb monazite crystallization age of 413.3 ± 2.1 Ma for the John Lee Brook Granite. The new geochronological together with new and existing geochemical data suggest that the protracted magmatic evolution of the Late Silurian to Early Devonian plutonic rocks is related to the transition of the Silurian Kingston arc-Mascarene backarc system from an extensional to compressional tectonic environment during collision of the Avalonian microcontinent with Laurentia followed by slab break-off.
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Leake, Bernard Elgey. "New light on the Oughterard Granite: Connemara's S-Type granite, Ireland." Irish Journal of Earth Sciences 41, no. 1 (2024): 33–43. http://dx.doi.org/10.1353/ijes.2023.a918662.
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Abstract: Most of the Connemara granites, including the Galway Granite batholith, have a clearly defined circular or ellipsoidal outcrop shape and are I-Type granites often with K-feldspar phenocrysts, whereas the Oughterard Granite (OG) forms numerous small intrusions scattered east-west over 40km with two larger linked bodies near Oughterard and is S-Type and aphyric. The only comprehensive mapping, mineralogical and chemical study of the OG was published over 50 years ago before the important 1974 recognition of the distinction of I- and S-Type granites was first made. New mapping of the southern Oughterard area with small OG intrusions is presented and many scattered published chemical and Rb, Sr, S and Pb isotopic studies integrated to confirm overall their individual conclusions that the peraluminous OG is of S-Type, being formed from melted Dalradian rocks as are the fluid-carried associated uneconomic mineral deposits. The OG is confined to the high sillimanite zone, mostly south of, and mainly later than, the 465-464Ma D4 Connemara Antiform, where a wide (>15km N-S) >70km E-W band of 469Ma gabbros and 467Ma quartz diorite gneisses intruded into already hot Dalradian rocks undergoing regional metamorphism. This generated the OG magmas by partial melting of pelites and semi-pelites. The upward intrusion of the OG magma was significantly delayed, as has been shown by precise dating in other granites elsewhere, to ∼464-461Ma during the late stages and mostly after D4 but before the country rocks had completely cooled. The OG intrusions as a whole probably form the second largest area of S-Type granite in Ireland, after the Leinster Granite.
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Raeva, Emilia, and Zlatka Cherneva. "Geochemistry of migmatite-granite connection: a case study from the Central Rhodope, Bulgaria." Geologica Balcanica 37, no. 1-2 (June 30, 2008): 53–59. http://dx.doi.org/10.52321/geolbalc.37.1-2.53.
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Extensive crustal melting and intrusive granite magmatism accompanied the extensional stage of the Rhodope massif Alpine evolution. Granites of different structural position and time of crystallization could reveal compositional and temporal relations between anatectic migmatization and granite magma generation. We have studied the post-kinematic Smilyan pluton and smaller syn-kinematic granite bodies hosted by the Madan unit metatexitic gneisses in the southwestern periphery of a metamorphic core complex known as Central Rhodopian Dome (CRD). The dominant geochemical features of the Madan unit granites display remarkable similarities with in situ formed anatectic melts from the CRD diatexitic core (Arda unit): felsic peraluminous compositions, low HFSE and REE, high LILE contents and LREE/HREE ratios, and negligible to positive Eu anomaly. Some deviations of the syn-kinematic granites geochemistry (metaluminous compositions, REE and HFSE enrichment, LREE/HREE ratios and Eu/Eu* variation) support an idea of separate partial melt batches extracted from different precursor compositions. Age data available (Smilyan pluton 43 Ma, and CRD core anatectic melts 37–38 Ma) preclude direct feedback relations between Madan unit intrusive granites and Arda unit migmatites. We infer that the migmatite-granite connection should be considered a common process of protracted Tertiary crustal melting that operated during CRD evolution and affected different crustal sources to produce discrete portions of granite melts. Major and trace elements geochemistry reveals potential lines of descent amongst groups of spatially related granitic rocks due to the same mechanism of melt generation.
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Sun, Deyou, Shicheng Wang, Jun Gou, Duo Zhang, Changzhou Deng, Dongguang Yang, and Li Tian. "Petrogenesis of Shihuiyao Rare-Metal Granites in the Southern Great Xing’an Range, NE China." Minerals 13, no. 5 (May 21, 2023): 701. http://dx.doi.org/10.3390/min13050701.
Full textAbstract:
Shihuiyao Rb–Nb–Ta-rich granites from the Late Jurassic period are newly discovered rare-metal-bearing granites found in the southern Great Xing’an Range, NE China. Further research of these granites may contribute to better understanding the petrogenesis of rare-metal granites and their associated mineralization mechanisms. The granites are high-silica (SiO2 = 73.66–77.08 wt%), alkali-rich (K2O + Na2O = 8.18–9.49 wt%) and weakly to mildly peraluminous with A/CNK values (molar ratios of Al2O3/(CaO + Na2O + K2O)) ranging from 1.06 to 1.16. High differentiation indexes (DI = 95–97) and low P2O5 contents demonstrate that Shihuiyao rocks are low-P and peraluminous rare-metal granites. Mineral chemistry and whole-rock geochemistry can be used to obtain the following lithological sequence: zinnwaldite granite, muscovite–zinnwaldite granite, amazonite-bearing granite and amazonite pegmatite. The effect of the rare-earth element tetrad; low K/Rb (18.98–32.82), Nb/Ta (2.41–4.64) and Zr/Hf (5.99–8.80) ratios; and the occurrence of snowball-textured quartz suggest that extreme magmatic fractionation might be the key factor that causes Rb–Nb–Ta enrichment.
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Naibaho, Tommy, and Lukman Arifin. "VERIFIKASI LITOLOGI TERHADAP NILAI KERENTANAN MAGNETIK DI PERAIRAN BANGKA BELITUNG." JURNAL GEOLOGI KELAUTAN 8, no. 1 (February 16, 2016): 37. http://dx.doi.org/10.32693/jgk.8.1.2010.184.
Full textAbstract:
Peta anomali magnetik menunjukkan bahwa perairan Bangka Belitung dicirikan oleh pasangan tinggian dan rendahan panjang gelombang anomali dengan amplitudo -200 nT—500nT. Sedangkan dari peta distribusi kerentanan magnetik, tinggian magnetik Belitung dibatasi oleh nilai kerentanan magnetik antara 0,001 cgs unit dan 0,003 cgs unit. Anomali positip rendah dicirikan oleh nilai kerentanan magnetik batuan antara 0,001-0,003 cgs unit merupakan benda intrusif bawah laut yang diduga berupa pluton granitik jenis granit-biotit yang berasosiasi dengan mineral kasiterit. Pluton granitik tersebut sama seperti granit yang berafiliasi dengan endapan timah di daratan Pulau Belitung. Misalnya singkapan granit yang terdapat di sekitar pantai Gembira yang menunjukkan tipe granit biotit porfiritik dengan fenokris ortoklas.
Kata Kunci: anomali magnetik, kerentanan magnetik, granit, Bangka Belitung
Magnetic anomaly map shows that the Bangka Belitung waters are characterized by a pair of hight and low long-wave amplitude anomalies values of -200 nT—500 nT. While the distribution map of magnetic susceptibility magnetic high of Belitung is limited magnetic susceptibility values of 0.001 cgs units and 0.003 cgs units. Positive anomaly of low magnetic is characterized susceptibility values between 0.001 to 0.003 cgs units suggested as a body of submerged intrusive rock body granitic plutons of granite biotite type associated with casiterite mineral. Granitic plutons are the same as granite affiliated with tin deposits in the mainland island of Belitung. For example there are granite outcrops around the Gembira coast that shows the type of porphyritic biotite granite with phenocrysts ortoclas.
Keywords: Magnetic anomaly, magnetic susceptibility, granite, Bangka Belitung
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Xiong, Yi-Qu, Yong-Jun Shao, Yanbo Cheng, and Shao-Yong Jiang. "Discrete Jurassic and Cretaceous Mineralization Events at the Xiangdong W(-Sn) Deposit, Nanling Range, South China." Economic Geology 115, no. 2 (March 1, 2020): 385–413. http://dx.doi.org/10.5382/econgeo.4704.
Full textAbstract:
Abstract The Xiangdong W(-Sn) deposit is hosted in the Dengfuxian multiphase granites (biotite, two-mica, and muscovite granites) within the Nanling Range metallogenic belt in south China. Previous studies suggested that the W(-Sn) mineralization in the Xiangdong deposit is related to the Late Jurassic two-mica granite, whereas recently W-Sn–bearing quartz veins have also been identified in muscovite granite. We present new cassiterite and zircon U-Pb ages to constrain the timing of W-Sn mineralization and related granitic magmatism. Our laser ablation-inductively coupled plasma-mass spectrometry U-Pb dating of zircon grains, combined with previous zircon ages, in addition to the trace element composition of the muscovite granite, suggest the muscovite granite in the Dengfuxian pluton was emplaced at 145 to 142 Ma and shows highly evolved features. Cassiterite grains from the ore-bearing veins in two-mica granite yielded U-Pb ages of 151.6 ± 3.7 and 141 to 138 Ma, whereas cassiterite grains from quartz veins occurring in muscovite granite yielded a U-Pb age of 136.8 ± 3.3 Ma. The new ages and detailed geologic evidence indicate that the Early Cretaceous muscovite granite is also genetically related to W-Sn mineralization. Combining this with previously published data from the Late Jurassic two-mica granites and related mineralization, we suggest that there were two stages of W-Sn mineralization at Xiangdong. Arsenopyrite geothermometry from the two stages suggests temperatures of 300° to 491° and 308° to 450°C in stage I and stage II, respectively. Wolframite grains from the two stages also show different characteristics and patterns for their major and trace elements. The enrichment in Sc in wolframite suggests low-pH and low-Eh conditions for a fluid containing F– and/or PO43− complexes during stage I, whereas higher contents of Nb and Ta and lower contents of Sc in wolframite from stage II indicate relatively lower pH and higher Eh conditions. In combination with data from other recent studies, we propose that the 145 to 130 Ma interval represents a newly recognized W-Sn metallogenic period linked with highly evolved granites in the Nanling Range metallogenic belt. The Early Cretaceous muscovite granite is an important new target for W and Sn resources in south China.
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Blevin, Phillip L., and Bruce W. Chappell. "The role of magma sources, oxidation states and fractionation in determining the granite metallogeny of eastern Australia." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 83, no. 1-2 (1992): 305–16. http://dx.doi.org/10.1017/s0263593300007987.
Full textAbstract:
ABSTRACTThe ore-element associations of granite-related ore deposits in the eastern Australian Palaeozoic fold belts can be related to the inferred relative oxidation state, halogen content and degree of fractional crystallisation within the associated granite suites. Sn mineralisation is associated with both S- and I-type granites that are reduced and have undergone fractional crystallisation. Cu and Au are associated with magnetite- and/or sphene-bearing, oxidised, intermediate I-type suites. Mo is associated with similar granites that are more fractionated and oxidised. W is associated with a variety of granite types and shows little dependence on inferred magma redox state. The observed ore deposit-granite type distribution in eastern Australia, and the behaviour of ore elements during fractionation, is consistent with models of ore element sequestering by sulphides and Fe-Ti phases (e.g. pyrrhotite, ilmenite, sphene, magnetite) whose stability is nominally fO2-dependent. Fractional crystallisation acts to amplify this process through the progressive removal of compatible elements and the concentration of incompatible elements into decreasing melt volumes. The halogen content is also important. S-type granites are poorer in Cl than I-types. Cl decreases and F increases in both S- and I-type granites with fractional crystallisation. Low Cl contents combined with low magma fO2 in themselves seem to provide an adequate explanation for the rarity of Mo, Cu, Pb and Zn type mineralisation with S-type granites. Although such properties of granite suites seem adequately to predict the associated ore-element assemblage to be expected in associated mineral deposits, additional factors determine whether or not there is associated economic mineralisation.
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Williams, Ian S., and Kenton S. W. Campbell. "Bruce William Chappell 1936–2012." Historical Records of Australian Science 28, no. 2 (2017): 146. http://dx.doi.org/10.1071/hr17012.
Full textAbstract:
Bruce Chappell was one of the most distinguished geologists of his generation whose contributions to understanding the origins of granites are both insightful and profound. A pioneer in the application of X-ray fluorescence spectrography to the analysis of geological materials, his radical ideas about magma genesis, still the subject of vigorous debate, have dominated and largely determined the global directions of subsequent research on granites. His restite model, the recognition that most granite magmas move bodily away from their source regions as a mixture of melt and solid residual material, the progressive separation of which determines the magma composition, underlies his tenet that granites are images of their source. His consequent recognition, with Allan White, that there are two fundamentally different types of granite magma, I-type (derived from igneous sources) and S-type (derived from weathered sedimentary sources), each with its distinctive evolutionary path and associated mineralization, continues to underpin research into granites worldwide, and the search for granite-related mineral deposits.
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Chen, Xu, Chunhua Wen, Debao Meng, Bin Li, Biguang Jiang, and Jinning Qin. "Implications of Major and Trace Element Migration in Altered Granites for Hydrothermal Alteration and Granite-Related Uranium Mineralization in the Sanjiu Ore Field, South China." Minerals 12, no. 2 (January 25, 2022): 144. http://dx.doi.org/10.3390/min12020144.
Full textAbstract:
The recently discovered Sanjiu ore field (SJOF) is a granite-related uranium ore field located in the middle of Zhuguangshan (South China). The relationship between hydrothermal alteration of granite and uranium mineralization in the SJOF is crucial yet understudied. In this study, the major- and trace-element contents of granite samples (fresh granite, altered granite, and tectonites) with different uranium contents were analyzed by using X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma–mass spectrometry (ICP–MS). The analytical results show a relative increase in Si, S, Ca, Pb, Mo, and Sb content in altered granites and tectonites, relative to fresh granites. During the mineralization stage, the increase of the aforementioned elements is related to various hydrothermal alterations (e.g., silicification, carbonation, sulfation, etc.) and newly formed minerals (e.g., microfine crystalline quartz veins; calcite agglomerates or fine veins; and metal sulfides, such as pyrite). There is a concomitant relative decrease in Na, K, Al, Fe, Mg, and other elemental contents that may be due to mineralogical alteration processes, such as biotite to chlorite, feldspar-group minerals to clay minerals, and redox of Fe-bearing minerals. The LREE/HREE ratio in altered granites decreases significantly with the increase in uranium content, suggesting that a low LREE/HREE ratio may be a prospecting indicator. The normalized trace-element patterns of mineralized granite (ore) and the relatively high U content of fresh granite imply that granitic rocks may be the primary uranium source in the SJOF. The uranium mineralization is mainly concentrated in the redox zone that occurs at a depth of 100−300 m. The redox zone is characterized by the most developed hydrothermal alterations and enrichment of trace elements, including W, Mo, Sb, Li, and the HREE.
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Li, Jian, Changwei Wang, Mingchun Song, Changjiang Wang, Shiyong Li, Xiao Liu, and Qingyi Cui. "Petrogenesis of the Laoshan Suite in the Jiaodong Peninsula (Eastern China): An Oxidized Low Ba–Sr A1-Type Granite." Minerals 13, no. 8 (July 29, 2023): 1012. http://dx.doi.org/10.3390/min13081012.
Full textAbstract:
The Jiaodong Peninsula is closely related to Mesozoic granites in terms of spatial and temporal aspects. However, the specific association between the genesis of gold mineralization and these granites remains unclear. It is also ambiguous why Laoshan-type granites, which are similar to Mesozoic granites, are not gold mineralized. In this study, we analyzed the Laoshan granites and compiled Mesozoic magmatic rock data (Linglong, Guojialing, and Weideshan suites) of the Jiaodong Peninsula. We performed whole-rock major and trace elements, LA–ICP–MS zircon U–Pb geochronology and geochemistry analyses. Our zircon U–Pb data denote that the Laoshan granite was emplaced during the 118 ± 1 Ma. The Laoshan granite is characterized by high SiO2 content (76.03–80.28 wt.%), high TFe2O3/MgO (11.1–27.1) and Ga/Al (3.0–3.5) ratios, high zircon saturation temperature (809–850 °C), and negative Eu (Eu/Eu* = 0.05–0.08) anomalies, showing A-type granite characteristics. Furthermore, the Laoshan granite is identified as an A1-type granite with low Ba (33.1–42.0 ppm) and Sr (14.1–21.0 ppm) contents. It was formed in an extensional tectonic environment induced by the subducting slab roll-back of the Paleo-Pacific Plate, mainly from the partial melting of lower crustal materials, mixed with a small amount of mantle components. Zircon trace elements indicate that the Laoshan suite had relatively high oxygen fugacity and temperature (ΔFMQ = + 2.43 to + 4.22, T-Ti in zircon (mean) = 796 °C) compared to the pre-mineralization and contemporaneous mineralization magma. We propose that oxidized adakitic magma (Weideshan suite) may contribute to the enrichment and mineralization of gold. Although Laoshan-type granite also has a high oxygen fugacity, its location is distant from the ore-controlling faults, which ultimately hinders the formation of gold mineralization. From the Jurassic to the Cretaceous, the tectonic and geochemical properties of magmatic rocks in the Jiaodong Peninsula have changed, and gold deposits are formed in such a transitional process (compression to extension, reduction to oxidation).
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Vapnik, Ye. "Melt inclusions in granitoids of the Timna Igneous Complex, Southern Israel." Mineralogical Magazine 62, no. 1 (February 1998): 29–40. http://dx.doi.org/10.1180/002646198547440.
Full textAbstract:
AbstractHigh temperature microthermometry and Scanning Electron Microprobe (SEM) analyses were used to study natural magmatic remnants in quartz crystals in granitoids from the Timna Igneous Complex, southern Israel, and to constrain physicochemical parameters during their crystallization. For the porphyritic granite, alkali granite and quartz monzodiorite, liquidus temperatures are 710–770, 770–830 and 770–840°C, respectively; solidus temperatures are 690–770, 710–790 and 770°C, respectively. Pressures during crystallization and water content in the magmas were determined using the phase diagram of the modal granite system. The determined P-T-conditions are typical for water-saturated granitoid magmas (>4–8 wt.%) generated and crystallized at a shallow crustal level.SEM data on melt inclusions support conclusions of previous investigations on two types of granitoid magmas exposed in the Timna Igneous Complex: the porphyritic and alkali granites. Different trends of crystallization are proposed for these granites. Crystallization of the porphyritic granite started with cotectic crystallization of plagioclase and terminated in residual K-feldspar-rich crystallization; crystallization of the alkali granite took place at higher temperatures, starting with K-rich alkali-feldspar crystallization and terminating in residual Na-rich eutectic crystallization.Parameters not available from other sources — temperature and pressure of the liquidus and solidus stages, water content, trends of crystallization — were obtained for the porphyritic and alkali granites.
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Y, Nguyen Viet, Pham Thi Dung, Tran Trong Hoa, Tran Tuan Anh, and Pham Trung Hieu. "Formation pressure - temperature (P-T) of Ye Yen Sun granite." VIETNAM JOURNAL OF EARTH SCIENCES 41, no. 2 (March 15, 2019): 173–81. http://dx.doi.org/10.15625/0866-7187/41/2/13735.
Full textAbstract:
Ye Yen Sun Cenozoic granitoid formations include biotite granite, fine- to medium-grained amphibol-biotite granite, and mostly undeformed fine- grained granite porphyry. Temperature calculation by the zircon saturation method gives the formation temperature ranging from about 680°C to 850°C; the pressure, determined on the basis of the major element composition, varies between 10 and 1 kbar (about 33 to 3.3 km deep). The granites viewed as "hot" or "intermediate" magmas were formed at the site of extension or transformation tectonics. Thus, the ability to form these granites due to the melting of the lower crust under the stretching region along the two wings of the Red River shear zone is a mechanism to be considered.
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Jefferies, N. L. "The distribution of the rare earth elements within the Carnmenellis pluton, Cornwall." Mineralogical Magazine 49, no. 353 (September 1985): 495–504. http://dx.doi.org/10.1180/minmag.1985.049.353.02.
Full textAbstract:
AbstractThe Carnmenellis pluton is a post-orogenic granite of Hercynian age, comprised largely of porphyritic biotite granites which possess LREE enriched patterns with slight negative Eu anomalies. Electron microprobe and ICP spectrometry data are presented for monazite, which occurs as an accessory mineral in all granite types, and it is demonstrated that this mineral is the principal host for LREE in the biotite granites. HREE are strongly partitioned into the accessory minerals xenotime, apatite, and zircon; only Eu substitutes significantly into the essential minerals. The behaviour of the REE during granite differentiation is controlled by the behaviour of the radioactive accessory minerals, which limits the usefulness of these elements in the petrogenetic modelling of granitic rocks.
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Ugidos, J. M., W. E. Stephens, A. Carnicero, and R. M. Ellam. "A reactive assimilation model for regional-scale cordierite-bearing granitoids: geochemical evidence from the Late Variscan granites of the Central Iberian Zone, Spain." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 99, no. 3-4 (December 2008): 225–50. http://dx.doi.org/10.1017/s1755691009008159.
Full textAbstract:
ABSTRACTRegional scale biotite and cordierite-bearing granites (s.l.) in the Variscan of the Central Iberian Zone (CIZ) are spatially closely associated with cordierite-rich nebulites and cordierite-bearing two-mica granites, and with cordierite-rich high grade hornfelses and cordieritites (>60% cordierite) that are relatively common in the aureoles of these granites. Building on published field evidence, petrological data are presented which, combined with new chemical and isotopic (Sr–Nd) modelling, indicate that the cordierite-bearing granites cannot be derived by simple anatexis of regional sedimentary protoliths; but the data are consistent with a process of reactive assimilation that involves the interaction of biotite granite magma with high-grade host rocks ranging from cordierite nebulites to andalusite-bearing cordieritites. The contribution of the postulated cordierite-rich contaminants to the diversity of cordierite granite compositions is modelled using the compositions of regional Lower Cambrian–Upper Neoproterozoic metasedimentary rocks that are generally chemically mature (CaO very rarely exceeds 1·4%). These rocks include specific horizons in which extreme chemical alteration is attributable to sediment reworking during eustatic falls in sea level. Such compositions may account for the presence of the high concentrations in Al that later produced cordieritites. Fractional crystallisation is also important, particularly in generating the more evolved cordierite granite and cordierite biotite muscovite granite compositions. Although assimilation in situ is normally regarded as a minor contributor volumetrically to evolving plutons, in this instance the emplacement of large volumes of granite magma into a high-T–low-P environment significantly increased the potential for reactive assimilation.
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Yin, Rong, Li Han, Xiao-Long Huang, Jie Li, Wu-Xian Li, and Lin-Li Chen. "Textural and chemical variations of micas as indicators for tungsten mineralization: Evidence from highly evolved granites in the Dahutang tungsten deposit, South China." American Mineralogist 104, no. 7 (July 1, 2019): 949–65. http://dx.doi.org/10.2138/am-2019-6796.
Full textAbstract:
Abstract The Dahutang tungsten deposit, located in the Yangtze Block, South China, is one of the largest tungsten deposits in the world. Tungsten mineralization is closely related to Mesozoic granitic plutons. A drill core through a pluton in the Dalingshang ore block in the Central segment of the Dahutang tungsten deposit shows that the pluton is characterized by multi-stage intrusive phases including biotite granite, muscovite granite, and Li-mica granite. The granites are strongly peraluminous and rich in P and F. Decreasing bulk-rock (La/Yb)N ratios and total rare earth element (ΣREE) concentrations from the biotite granite to muscovite granite and Li-mica granite suggest an evolution involving the fractional crystallization of plagioclase. Bulk-rock Li, Rb, Cs, P, Sn, Nb, and Ta contents increase with decreasing Zr/Hf and Nb/Ta ratios, denoting that the muscovite granite and Li-mica granite have experienced a higher degree of magmatic fractionation than the biotite granite. In addition, the muscovite and Li-mica granites show M-type lanthanide tetrad effect, which indicates hydrothermal alteration during the post-magmatic stage. The micas are classified as lithian biotite and muscovite in the biotite granite, muscovite in the muscovite granite, and Li-muscovite and lepidolite in the Li-mica granite. The Li, F, Rb, and Cs contents of micas increase, while FeOT, MgO, and TiO2 contents decrease with increasing degree of magmatic fractionation. Micas in the muscovite granite and Li-mica granite exhibit compositional zonation in which Si, Rb, F, Fe, and Li increase, and Al decreases gradually from core to mantle, consistent with magmatic differentiation. However, the outermost rim contains much lower contents of Si, Rb, F, Fe, and Li, and higher Al than the mantle domains due to metasomatism in the presence of fluids. The variability in W contents of the micas matches the variability in Li, F, Rb, and Cs contents, indicating that both the magmatic and hydrothermal evolutions were closely associated with W mineralization in the Dahutang deposit. The chemical zoning of muscovite and Li-micas not only traces the processes of W enrichment by magmatic differentiation and volatiles but also traces the leaching of W by the fluids. Therefore, micas are indicators not only for the magmatic–hydrothermal evolution of granite, but also for tungsten mineralization.
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Amuda, Abdulgafar Kayode, Shuang Li, Xiaoyong Yang, Jingya Cao, and Mohamed Faisal. "Genetic Association between Granites and Mineralization at the Gindi Akwati Cassiterite–Sulfide Deposit, North-Central Nigeria: Insights from Mineralogy, Fluid Inclusions, and Sulfur Isotopes." Minerals 12, no. 6 (June 15, 2022): 761. http://dx.doi.org/10.3390/min12060761.
Full textAbstract:
The cassiterite–sulfide mineralization occurs within quartz veins and greisenized Precambrian Older Granite around the Gindi Akwati region at the Ropp complex’s western boundary, north-central Nigeria. The intrusion of Jurassic Younger granite porphyry sheared the marginal parts of the Older Granite and the mylonitized zone created pathways for fluids that escaped during the late-stage consolidation of Jurassic biotite granite. The biotite granites are highly differentiated (K/Rb < 200), peraluminous (A/CNK > 1), high-K, and have high Sn concentrations (average = 117 ppm). The intrusion of Jurassic granite porphyry forced Older Granite interaction with ore-bearing fluid that escaped from Jurassic biotite granite under low oxygen fugacity at or below the NNO buffer. The above fluid–rock interaction caused mass changes in host granite during greisenization and redistributed ores in the vicinity of the shears. This suggests that chloride ions take the form of significant complex-forming ligands and efficiently sequestrate, transport, and deposit ore metals (Sn, Zn, Fe, and Cu) locally within the greisenized granites and quartz veins. The redox potential of the ores probably gave a false impression of metal zoning with a relatively higher abundance of the oxide ore than the sulfides at the surface. The alteration mineralogy (quartz-, topaz-, lepidolite-, and fluorite-bearing assemblages) coupled with S isotope and fluid inclusion systematic data suggests the hydrothermal history of “greisens” and veins started with hot (homogenization temperature ≥300 °C), low to moderate salinity (average = 4.08 wt. % NaCl), low density (≤0.6 g/cm3) fluids and ≥ 200 bar trapping pressure. The sulfide isotopic composition (δ34SV-CDT = −1.30 to + 0.87 ‰) is very similar to typical magmatic fluids, indicating late-magmatic to early post-magmatic models of mineralization related to the anorogenic granite intrusions.
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Zan, Pei, Shouyu Chen, Jinduo Chen, and Shengli Li. "Early Paleozoic Adakitic Granitoids from the Xingshuping Gold Deposit of East Qinling, China: Petrogenesis and Tectonic Significance." Minerals 11, no. 10 (September 23, 2021): 1032. http://dx.doi.org/10.3390/min11101032.
Full textAbstract:
This study discussed the pertrological classification, geochronology, petrogenesis and tectonic evolution of early Paleozoic granites from the Xingshuping gold deposit in the East Qinling orogenic belt. In order to achieve this target, we carried out an integrated study of zircon U–Pb age, whole-rock major and trace elements, as well as Sr–Nd–Hf isotope compositions for the Xingshuping granites (part of the Wuduoshan pluton) from the Erlangping unit. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U–Pb dating constrains the emplacement age of the Xingshuping granites at 446.2 ± 1.2 Ma. The rocks at Xingshuping can be divided into two types: mainly biotite granite and monzonitic granite. The biotite granites are typical adakitic rocks, while the monzonitic granites show characteristics similar to normal arc volcanic rocks. The geochemical compositions reveal that they were derived from a clay-rich, plagioclase-rich and biotite-rich psammitic lower continental crust source, with contributions of mantle-derived magmas. The distinction is that the biotite granites were primarily derived from partial melting in a syn-collision extension setting, whereas the monzonitic granite went through a fractional crystallization process in an intraplate anorogenic setting.
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Liu, Shiyu, Yuping Liu, Lin Ye, Chen Wei, Yi Cai, and Weihong Chen. "Genesis of Dulong Sn-Zn-In Polymetallic Deposit in Yunnan Province, South China: Insights from Cassiterite U-Pb Ages and Trace Element Compositions." Minerals 11, no. 2 (February 13, 2021): 199. http://dx.doi.org/10.3390/min11020199.
Full textAbstract:
The Dulong Sn-Zn-In polymetallic deposit in the Yunnan province, SW China, hosts a reserve of 5.0 Mt Zn, 0.4 Mt Sn, and 7 Kt In. It is one of the most important polymetallic tin ore districts in China. Granites at Dulong mining area include mainly the Laojunshan granite (third phase), which occurs as quartz porphyry or granite porphyry dikes in the Southern edge of the Laojunshan intrusive complex. Granites of phases one and two are intersected at drill holes at depth. There are three types of cassiterite mineralization developed in the deposit: cassiterite-magnetite ± sulfide ore (Cst I), cassiterite-sulfide ore (Cst II) within the proximal skarn in contact with the concealed granite (granites of phases one to two and three), and cassiterite-quartz vein ore (Cst III) near porphyritic granite. Field geology and petrographic studies indicate that acid neutralising muscovitization and pyroxene reactions were part of mechanisms for Sn precipitation resulting from fluid-rock interaction. In situ U–Pb dating of cassiterite samples from the ore stages of cassiterite-sulfide (Cst II) and Cassiterite-quartz vein (Cst III) yielded Tera-Wasserburg U–Pb lower intercept ages of 88.5 ± 2.1 Ma and 82.1 ± 6.3 Ma, respectively. The two mineralization ages are consistent with the emplacement age of the Laojunshan granite (75.9–92.9 Ma) within error, suggesting a close temporal link between Sn-Zn(-In) mineralization and granitic magmatism. LA-ICPMS trace element study of cassiterite indicates that tetravalent elements (such as Zr, Hf, Ti, U, W) are incorporated in cassiterite by direct substitution, and the trivalent element (Fe) is replaced by coupled substitution. CL image shows that the fluorescence signal of Cst I–II is greater than that of Cst III, which is caused by differences in contents of activating luminescence elements (Al, Ti, W, etc.) and quenching luminescence element (Fe). Elevated W and Fe but lowered Zr, Hf, Nb, and Ta concentrations of the three type cassiterites from the Dulong Sn-Zn-In polymetallic deposit are distinctly different from those of cassiterites in VMS/SEDEX tin deposits, but similar to those from granite-related tin deposits. From cassiterite-magnetite ± sulfide (Cst I), cassiterite-sulfide ore (Cst II), to cassiterite-quartz vein ore-stage (Cst III), high field strength elements (HFSEs: Zr, Nb, Ta, Hf) decrease. This fact combined with cassiterite crystallization ages, indicates that Cst I–II mainly related to concealed granite (Laojunshan granites of phases one and two) while Cst III is mainly related to porphyritic granite (Laojunshan granites of phase three).
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Dai, Hongzhang, Denghong Wang, Xin Li, Shanbao Liu, Chenghui Wang, and Yan Sun. "Genesis of the Wuzhutang Granite and Associated W–Sn–Be Mineralization in the Xuebaoding Mining Area, Sichuan Province, China." Minerals 12, no. 8 (August 5, 2022): 993. http://dx.doi.org/10.3390/min12080993.
Full textAbstract:
The Xuebaoding W–Sn–Be mining area, located in the Songpan–Garze orogenic belt in western China, is known for producing large, colorful, euhedral crystals of scheelite, cassiterite, and tabular beryl. Zircon LA-ICP-MS U–Pb dating of the Wuzhutang granite yields a concordia age of 218.96 ± 2.1 Ma, and a weighted mean 206Pb/238U age of 218.98 ± 1.12 Ma. Cassiterite LA-MC-ICPMS dating of the quartz vein bearing beryl, cassiterite, and scheelite, yields a concordant age of 213.5 ± 1.7 Ma. These observations indicate that magmatic activities and mineralization on the western side of the Zibaishan dome occurred during the late Indosinian, prior to their occurrence on the eastern side of the dome, reflecting the fact that the granite may have undergone two epochs of magmatic evolution and metallogenic processes. Geochemical analysis revealed that the Wuzhutang granite has relatively high A/CNK (average: 1.05) and differentiation index (DI; 81.16~85.88) values, and that they are enriched in W, Sn, Be, Li, and Cs. Unlike the Pukouling and Pankou granites, the Wuzhutang granite contains a certain amount of plagioclase and relatively high contents of Ba (633~1007 ppm) and Sr (334~411 ppm). Sr–Nd–Pb isotope values (87Sr/86Sr(t) = 0.70747–0.70865, εNd(t) = −6.35 to –4.34, 206Pb/204Pb = 18.186–18.3, 207Pb/204Pb = 15.556–15.592, and 208Pb/204Pb = 38.268–38.432) indicate a Mesoproterozoic basement origin for the Wuzhutang granite. We suggest the three granites belong to a peraluminous magma system and were derived by partial melting of the upper crust, the magma of the Wuzhutang granite originated from a deeper source and exhibits a lower degree of differentiation than that of the Pankou and Pukouling granites.
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Graham, N. T., M. Feely, and B. Callaghan. "Plagioclase-rich microgranular inclusions from the late-Caledonian Galway Granite, Connemara, Ireland." Mineralogical Magazine 64, no. 1 (February 2000): 113–20. http://dx.doi.org/10.1180/002646100549030.
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AbstractWe report on the occurrence, petrology and geochemistry of recently recognized leucocratic plagioclase-rich microgranular inclusions hosted by two granite facies in the late-Caledonian Galway Granite, Connemara, Ireland. They have been recorded at 66 localities along an ESE trending, 4 km wide corridor which incorporates the contact zone between their host granites (i.e. The Megacrystic Granite and the Mingling and Mixing Zone Granodiorite). The inclusions are discoidal in shape and oriented parallel to the general ESE trending foliation in the granites with the most elongate (6.0 × 0.6 cm) occurring in zones of strongest fabric intensity. Contacts between the inclusions and the host granite are sharp with no chilled margin visible. They display a fine-grained (<1 mm) interlocking texture with occasional crystals of plagioclase ranging up to 2 mm in length. Microprobe analysis shows that the plagioclase is essentially oligoclase (An22–32) in composition and is similar to that (i.e. An21–30) occurring in the host granites. Furthermore, the oligoclase accounts for between 61 and 78% of the mode which is reflected in the major element chemistry of the inclusions. Other minerals (in decending order of abundance) include K-feldspar, quartz, biotite and magnetite. The origin of the inclusions is unclear. However, the results of the microprobe analysis provide evidence of a link between them and their host granites.
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Lee, Byung Choon, Weon-Seo Kee, Uk Hwan Byun, and Sung Won Kim. "Statherian (ca. 1714–1680 Ma) Extension-Related Magmatism and Deformation in the Southwestern Korean Peninsula and Its Geological Significance: Constraints from the Petrological, Structural, Geochemical and Geochronological Studies of Newly Identified Granitoids." Minerals 11, no. 6 (May 24, 2021): 557. http://dx.doi.org/10.3390/min11060557.
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In this study, petrological, structural, geochemical, and geochronological analyses of the Statherian alkali feldspar granite and porphyritic alkali feldspar granite in the southwestern part of the Korean Peninsula were conducted to examine petrogenesis of the granitoids and their tectonic setting. Zircon U-Pb dating revealed that the two granites formed around 1.71 Ga and 1.70–1.68 Ga, respectively. The results of the geochemical analyses showed that both of the granites have a high content of K2O, Nb, Ta, and Y, as well as high FeOt/MgO and Ga/Al ratios. Both granites have alkali-calcic characteristics with a ferroan composition, indicating an A-type affinity. Zircon Lu-Hf isotopic compositions yielded negative εHf(t) values (−3.5 to −10.6), indicating a derivation from ancient crustal materials. Both granite types underwent ductile deformation and exhibited a dextral sense of shear with a minor extension component. Based on field relationships and zircon U-Pb dating, it was considered that the deformation event postdated the emplacement of the alkali feldspar granite and terminated soon after the emplacement of the porphyritic alkali feldspar granite in an extensional setting. These data indicated that there were extension-related magmatic activities accompanying ductile deformation in the southwestern part of the Korean Peninsula during 1.71–1.68 Ga. The Statherian extension-related events are well correlated with those in the midwestern part of the Korean and eastern parts of the North China Craton.
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Starikova, A. E., E. V. Sklyarov, and V. V. Sharygin. "Y-REE mineralization in biotite-arfvedsonite granites of the Katugin rare-metal deposit, Transbaikalia, Russia." Доклады Академии наук 487, no. 1 (July 19, 2019): 88–92. http://dx.doi.org/10.31857/s0869-5652487188-92.
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We provide the results of study of the extremely enriched in Y-REE carbonate-fluorine isolations from biotite-arfvedsonite granite of the Katugin rare metal deposit. New chemical data of isolations mineral phases - gagarinite-(Y), tveitite-(Y), fluocerite-(Ce), basnaesite, fluornatropyroclore, are delivered. Carbonate-fluoride globule in quartz of hosting granite gives possibility to estimate crystallization order. This finding might be the evidence of silicate-fluorine immiscibility suggested before for Y-REE segregations in the Katugin granites. Fluorine melt segregation took likely place at the magmatic stage of biotite-arfvedsonite granite formation. It causes host granite depletion with fluorine and redistribution of REE and Y in fluorine salt melt.
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Guo, Zhongping, Jian Li, Yongqi Song, Chengqian He, and Fuyu Zhang. "The Size Effect and Microstructure Changes of Granite after Heat Treatment." Advances in Materials Science and Engineering 2021 (July 1, 2021): 1–14. http://dx.doi.org/10.1155/2021/9958255.
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High temperature can change the mechanical properties of granite, with significant nonlinear characteristics, and at the same time change its microstructure. Therefore, two kinds of granites are used in this paper: one is normal temperature granite and the other is granite treated at 600°C, and a detailed comparative study is made. The fracture toughness of two kinds of rocks was tested by fracture tests, and the results were analyzed by a nonlinear fracture mechanics model (SEL). At the same time, in order to understand the influence of high temperature on the mineral composition and microstructure of granite, XRD, optical microscope, and SEM were used to observe the mineral composition, microcracks, and fracture morphology of granite. The results show the following: (1) high temperature significantly changes the fracture mechanics parameters of granite. The fracture toughness of granite treated at 600°C is significantly lower than that of untreated granite, which is reduced by more than 60%. (2) No obvious size effect was found in the untreated granite, while the size effect of the granite after treatment at 600°C was significant. (3) The granite after high-temperature treatment showed strong nonlinear characteristics, and the SEL can reasonably describe and explain its nonlinear fracture characteristics. (4) The brittleness of the granite treated at 600°C decreased and the ductility increased. The microscopic morphology of the fracture was rough, with obvious steps and rivers. The microcracks and porosity had increased significantly, but the main components did not change significantly.