Journal articles: 'Quartzite. Petrology Geology'

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Davis, Richard A. "Precambrian tidalites from the Baraboo Quartzite Wisconsin, U.S.A." Marine Geology 235, no. 1-4 (December 2006): 247–53. http://dx.doi.org/10.1016/j.margeo.2006.10.018.

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Intan, Muh Fadhlan S. "EKSPLORASI GEOARKEOLOGI SITUS PALEOLITIK DI PULAU SERAM, PROVINSI MALUKU [Geoarchaeological Exploration of Paleolitical Sites on The Island of Seram, Moluccas Province]." Jurnal Penelitian Arkeologi Papua dan Papua Barat 9, no. 1 (May 30, 2018): 1–20. http://dx.doi.org/10.24832/papua.v9i1.203.

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East Seram District, Central Maluku, and West Seram regency is located on the island of Seram, where research was conducted, save a lot of cultural, one of the paleolithic period, which is a long time not received attention from environmental researchers. It is used as the basis of the main issues that include geology in general. Therefore, the purpose of this study was to perform surface geological mapping in general as one of the efforts to provide geological information, while the goal is to determine aspects of geomorphology, stratigraphy, structural geology associated with the existence of paleolithic sites in the study area. The research method begins with a literature review, surveys, analysis, and interpretation of field data. Environmental scanning provides information about the landscape consists of plains morphological units, units of corrugated morphology weak, strong corrugated morphology unit, and units of karst morphology. The river berstadia old-mature river stadium, periodical/permanent river, and river episodic/intermittent river. Constituent rock is sandstone, limestone, marl, andesite, tuff, schist, volcanic breccias, reef limestones, conglomerates, and alluvial. Geological structures such as faults and folds. Ceram Research discovered 14 Paleolithic sites. From the analysis of petrology, lithic tools made of jasper rocks, chert, metalimestone, flint, and quartzite. Rock as raw material litik tool, found in the middle of Seram Island, then spread to the west and to the east which has a flat relief. ABSTRAKKabupaten Seram Bagian Timur, Kabupaten Maluku Tengah, dan Kabupaten Seram Bagian Barat terletak di Pulau Seram, yang menjadi lokasi penelitian, menyimpan banyak tinggalan budaya, salah satunya dari masa paleolitik, yang sekian lama tak mendapat perhatian dari para peneliti lingkungan. Hal inilah yang dijadikan dasar permasalahan utama yang mencakup geologi secara umum. Oleh sebab itu, maksud penelitian ini dalah untuk melakukan pemetaan geologi permukaan secara umum sebagai salah satu upaya untuk menyajikan informasi geologi, sedangkan tujuannya adalah untuk mengetahui aspek-aspek geomorfologi, stratigrafi, struktur geologi yang dikaitkan dengan keberadaan di situs-situs paleolitik wilayah penelitian. Metode penelitian diawali dengan kajian pustaka, survei, analisis, dan interpretasi data lapangan. Pengamatan lingkungan memberikan informasi tentang bentang alamnya terdiri yang dari satuan morfologi dataran, satuan morfologi bergelombang lemah, satuan morfologi bergelombang kuat, dan satuan morfologi karst. Sungainya berstadia sungai dewasa-tua, sungai periodik/permanen, dan sungai episodik/ intermittent. Batuan penyusun adalah batupasir, batugamping, napal, andesit, tufa, sekis, breksi volkanik, batugamping terumbu, konglomerat, dan aluvial. Struktur geologi berupa patahan, dan lipatan. Eksplorasi di Pulau Seram telah menemukan 14 situs paleolitik. Dari analisis petrologi, alat-alat litik terbuat dari batuan jasper, chert, metagamping, batuapi, dan kuarsit. Batuan sebagai bahan baku alat litik, ditemukan di bagian tengah Pulau Seram, lalu disebarkan ke arah barat dan timur yang berelief datar.

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Mazumder, Rajat, and Martin J. Van Kranendonk. "Palaeoproterozoic terrestrial sedimentation in the Beasley River Quartzite, lower Wyloo Group, Western Australia." Precambrian Research 231 (July 2013): 98–105. http://dx.doi.org/10.1016/j.precamres.2013.03.018.

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Andersen, Tom, Kauko Laajoki, and Ayesha Saeed. "Age, provenance and tectonostratigraphic status of the Mesoproterozoic Blefjell quartzite, Telemark sector, southern Norway." Precambrian Research 135, no. 3 (November 2004): 217–44. http://dx.doi.org/10.1016/j.precamres.2004.08.006.

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Fu, B., J. L. R. Touret, and Y. F. Zheng. "Fluid inclusions in coesite-bearing eclogites and jadeite quartzite at Shuanghe, Dabie Shan (China)." Journal of Metamorphic Geology 19, no. 5 (September 2001): 531–47. http://dx.doi.org/10.1046/j.0263-4929.2001.00327.x.

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Vdovets, A. Z. "Variability of Alunite Quartzite Composition as a Reflection of the Characteristics of Its Genesis." Geology of Ore Deposits 62, no. 2 (March 2020): 138–62. http://dx.doi.org/10.1134/s1075701520020063.

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He, Mingzhao, and Eric Forssberg. "Influence of slurry rheology on stirred media milling of quartzite." International Journal of Mineral Processing 84, no. 1-4 (October 2007): 240–51. http://dx.doi.org/10.1016/j.minpro.2006.08.001.

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Malone, D. H., J. P. Craddock, P. K. Link, B. Z. Foreman, M. A. Scroggins, and J. Rappe. "Detrital zircon geochronology of quartzite clasts, northwest Wyoming: Implications for Cordilleran Neoproterozoic stratigraphy and depositional patterns." Precambrian Research 289 (February 2017): 116–28. http://dx.doi.org/10.1016/j.precamres.2016.12.011.

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Chen, Y. X., Y. F. Zheng, and Z. Hu. "Petrological and zircon evidence for anatexis of UHP quartzite during continental collision in the Sulu orogen." Journal of Metamorphic Geology 31, no. 4 (January 25, 2013): 389–413. http://dx.doi.org/10.1111/jmg.12026.

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Nabelek, P. I., S. K. Stephenson, S. S. Morgan, and J. J. Student. "Properties of fluids attending variable recrystallization of quartzite during contact metamorphism in the White-Inyo Range, California." Journal of Metamorphic Geology 35, no. 3 (December 15, 2016): 357–69. http://dx.doi.org/10.1111/jmg.12235.

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MOTOYOSHI, Y., B. J. HENSEN, and H. MATSUEDA. "Metastable growth of corundum adjacent to quartz in a spinel-bearing quartzite from the Archaean Napier Complex, Antarctica." Journal of Metamorphic Geology 8, no. 1 (January 1990): 125–30. http://dx.doi.org/10.1111/j.1525-1314.1990.tb00459.x.

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Kidder, S., J. P. Avouac, and Y. C. Chan. "Application of titanium-in-quartz thermobarometry to greenschist facies veins and recrystallized quartzites in the Hsüehshan range, Taiwan." Solid Earth 4, no. 1 (January 7, 2013): 1–21. http://dx.doi.org/10.5194/se-4-1-2013.

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Abstract. The accuracy, reliability and best practises of Ti-in-quartz thermobarometry (TitaniQ) in greenschist facies rocks have not been established. To address these issues, we measured Ti concentrations in rutile-bearing samples of moderately deformed, partially recrystallized quartzite and vein quartz from the Hsüehshan range, Taiwan. The spread of Ti concentrations of recrystallized grains in quartzite correlates with recrystallized grain size. Recrystallized quartz (grain size ~100–200 μm) that formed during early deformation within the biotite stability field shows a marked increase in intermediate Ti-concentration grains (~1–10 ppm) relative to detrital porphyroclasts (Ti ~0.1–200 ppm). Fine recrystallized quartz (~5% of the samples by area, grain size ~10–20 μm) has a further restricted Ti concentration peaking at 0.8–2 ppm. This trend suggests equilibration of Ti in recrystallized quartz with a matrix phase during deformation and cooling. Unlike previously documented examples, Ti concentration in the quartzite is inversely correlated with blue cathodoluminescence. Deformation was associated with a minimum grain boundary diffusivity of Ti on the order of 10−22m2 s−1. Vein emplacement and quartzite recrystallization are independently shown to have occurred at 250–350 °C and 300–410 °C, respectively, with lithostatic pressure of 3–4 kbar (assuming a geothermal gradient of 25° km−1), and with hydrostatic fluid pressure. Estimates of the accuracy of TitaniQ at these conditions depend on whether lithostatic or fluid pressure is used in the TitaniQ calibration. Using lithostatic pressure and these temperatures, the Thomas et al. (2010) calibration yields Ti concentrations within error of concentrations measured by SIMS. If fluid pressure is instead used, predicted temperatures are ~30–40 °C too low. TitaniQ has potential to yield accurate PT information for vein emplacement and dynamic recrystallization of quartz at temperatures as low as ~250 °C, however clarification of the relevant pressure term and further tests in rutile-present rocks are warranted.

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Rath, S. S., H. Sahoo, S. K. Das, B. Das, and B. K. Mishra. "Influence of band thickness of banded hematite quartzite (BHQ) ore in flotation." International Journal of Mineral Processing 130 (July 2014): 48–55. http://dx.doi.org/10.1016/j.minpro.2014.05.006.

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WOHLERS, A., and L. P. BAUMGARTNER. "Melt infiltration into quartzite during partial melting in the Little Cottonwood Contact Aureole (UT, USA): implication for xenocryst formation." Journal of Metamorphic Geology 31, no. 3 (December 31, 2012): 301–12. http://dx.doi.org/10.1111/jmg.12022.

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15

Barr, S. M., D. W. Davis, S. Kamo, and C. E. White. "Significance of U–Pb detrital zircon ages in quartzite from peri-Gondwanan terranes, New Brunswick and Nova Scotia, Canada." Precambrian Research 126, no. 1-2 (September 2003): 123–45. http://dx.doi.org/10.1016/s0301-9268(03)00192-x.

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WANG, L., Z. M. JIN, T. KUSKY, H. J. XU, and X. W. LIU. "Microfabric characteristics and rheological significance of ultra-high-pressure metamorphosed jadeite-quartzite and eclogite from Shuanghe, Dabie Mountains, China." Journal of Metamorphic Geology 28, no. 2 (February 2010): 163–82. http://dx.doi.org/10.1111/j.1525-1314.2009.00859.x.

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Chakrabarti, Kalyan, Joydip Mukhopadhyay, Gautam Ghosh, A. K. Bhatt, and D. K. Sinha. "Transition from alluvial to wave-tide-dominated Meso-Neoarchean shelf sedimentation in the Mankarchua Quartzite, Singhbhum craton, eastern India." Precambrian Research 354 (March 2021): 106020. http://dx.doi.org/10.1016/j.precamres.2020.106020.

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Lahtinen, R., and M. Nironen. "Paleoproterozoic lateritic paleosol–ultra-mature/mature quartzite–meta-arkose successions in southern Fennoscandia—intra-orogenic stage during the Svecofennian orogeny." Precambrian Research 183, no. 4 (December 2010): 770–90. http://dx.doi.org/10.1016/j.precamres.2010.09.006.

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Kanygina, Nadezhda A., Andrey A. Tretyakov, Kirill E. Degtyarev, Victor P. Kovach, Sergei Yu Skuzovatov, Kwan-Nang Pang, Kuo-Lung Wang, and Hao-Yang Lee. "Late Mesoproterozoic–early Neoproterozoic quartzite–schist sequences of the Aktau–Mointy terrane (Central Kazakhstan): Provenance, crustal evolution, and implications for paleotectonic reconstruction." Precambrian Research 354 (March 2021): 106040. http://dx.doi.org/10.1016/j.precamres.2020.106040.

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Al- Zubaidi, Aqeel A., Varoujan Sissakian, and Hassan K. Jassim. "PETROLOGY AND PROVENANCE OF THE NATURAL STONE TOOLS FROM Al-DALMAJ ARCHAEOLOGICAL SITE, MESOPOTAMIAN PLAIN, IRAQ." Bulletin of the Iraq Natural History Museum 16, no. 3 (June 20, 2021): 231–51. http://dx.doi.org/10.26842/binhm.7.2021.16.3.0231.

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Many stone tools were found on a hill south of the Hor Al-Dalmaj which is located in the central part of the alluvial plain of Mesopotamia, between the Tigris and Euphrates Rivers. The types of rocks from which the studied stone tools were made are not found in the alluvial plain, because it consists of friable sand, silt, and clay. All existing sediments were precipitated in riverine environments such as point bar, over bank, and floodplain sediments. The collected stone tools were described with a magnifying glass (10 x) and a polarized microscope after they were thin sectioned. Microscopic analysis showed that these stone tools are made of sedimentary, volcanic igneous and metamorphic rocks, such as: sandstones, limestones, chert, conglomerate, rhyolite, basalt, mica schist, and quartzite. The current studied stone tools were used by ancient humans as pestles, querns, scrapers, and knives. The present study showed that these tools were transported from outside the alluvial plain of Mesopotamia. A stone tool at the archaeological site of Al-Dalmaj indicates that there were some trade routes that connected this site with its surrounding; in addition to the economic, and that might occurred cultural exchanges during the Neolithic Period.

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Kilian, Rüdiger, and Renée Heilbronner. "Analysis of crystallographic preferred orientations of experimentally deformed Black Hills Quartzite." Solid Earth 8, no. 5 (October 25, 2017): 1095–117. http://dx.doi.org/10.5194/se-8-1095-2017.

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Abstract. The crystallographic preferred orientations (textures) of three samples of Black Hills Quartzite (BHQ) deformed experimentally in the dislocation creep regimes 1, 2 and 3 (according to Hirth and Tullis, 1992) have been analyzed using electron backscatter diffraction (EBSD). All samples were deformed to relatively high strain at temperatures of 850 to 915 °C and are almost completely dynamically recrystallized. A texture transition from peripheral [c] axes in regime 1 to a central [c] maximum in regime 3 is observed. Separate pole figures are calculated for different grain sizes, aspect ratios and long-axis trends of grains, and high and low levels of intragranular deformation intensity as measured by the mean grain kernel average misorientation (gKAM). Misorientation relations are analyzed for grains of different texture components (named Y, B, R and σ grains, with reference to previously published prism, basal, rhomb and σ1 grains). Results show that regimes 1 and 3 correspond to clear end-member textures, with regime 2 being transitional. Texture strength and the development of a central [c]-axis maximum from a girdle distribution depend on deformation intensity at the grain scale and on the contribution of dislocation creep, which increases towards regime 3. Adding to this calculations of resolved shear stresses and misorientation analysis, it becomes clear that the peripheral [c]-axis maximum in regime 1 is not due to deformation by basal 〈a〉 slip. Instead, we interpret the texture transition as a result of different texture forming processes, one being more efficient at high stresses (nucleation or growth of grains with peripheral [c] axes), the other depending on strain (dislocation glide involving prism and rhomb 〈a〉 slip systems), and not as a result of temperature-dependent activity of different slip systems.

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Pidgeon, R. T., and A. A. Nemchin. "High abundance of early Archaean grains and the age distribution of detrital zircons in a sillimanite-bearing quartzite from Mt Narryer, Western Australia." Precambrian Research 150, no. 3-4 (November 2006): 201–20. http://dx.doi.org/10.1016/j.precamres.2006.07.008.

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23

De, Saheli. "Alluvial fan to shallow marine sedimentation record in the ~3.0 Ga Keonjhar Quartzite, Singhbhum Craton, India: An example of Phanerozoic style passive margin sedimentation from the Mesoarchean." Precambrian Research 352 (January 2021): 105962. http://dx.doi.org/10.1016/j.precamres.2020.105962.

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Heilbronner, Renée, and Rüdiger Kilian. "The grain size(s) of Black Hills Quartzite deformed in the dislocation creep regime." Solid Earth 8, no. 5 (October 17, 2017): 1071–93. http://dx.doi.org/10.5194/se-8-1071-2017.

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Abstract. General shear experiments on Black Hills Quartzite (BHQ) deformed in the dislocation creep regimes 1 to 3 have been previously analyzed using the CIP method (Heilbronner and Tullis, 2002, 2006). They are reexamined using the higher spatial and orientational resolution of EBSD. Criteria for coherent segmentations based on c-axis orientation and on full crystallographic orientations are determined. Texture domains of preferred c-axis orientation (Y and B domains) are extracted and analyzed separately. Subdomains are recognized, and their shape and size are related to the kinematic framework and the original grains in the BHQ. Grain size analysis is carried out for all samples, high- and low-strain samples, and separately for a number of texture domains. When comparing the results to the recrystallized quartz piezometer of Stipp and Tullis (2003), it is found that grain sizes are consistently larger for a given flow stress. It is therefore suggested that the recrystallized grain size also depends on texture, grain-scale deformation intensity, and the kinematic framework (of axial vs. general shear experiments).

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Hinchey, Alana M., Sharon D. Carr, and Nicole Rayner. "Bulk compositional controls on the preservation of age domains within metamorphic monazite: A case study from quartzite and garnet–cordierite–gedrite gneiss of Thor-Odin dome, Monashee complex, Canadian Cordillera." Chemical Geology 240, no. 1-2 (May 2007): 85–102. http://dx.doi.org/10.1016/j.chemgeo.2007.02.001.

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Klevakina, K., J. Renner, N. Doltsinis, and W. Adeagbo. "Transport processes at quartz–water interfaces: constraints from hydrothermal grooving experiments." Solid Earth 5, no. 2 (August 27, 2014): 883–99. http://dx.doi.org/10.5194/se-5-883-2014.

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Abstract. We performed hydrothermal annealing experiments on quartzite samples at temperatures of 392 to 568 °C and fluid pressures of 63 to 399 MPa for up to 120 h, during which hydrothermal grooves developed on the free surfaces of the samples. An analysis of surface topology and groove characteristics with an atomic force microscope revealed a range of surface features associated with the simultaneous and successive operation of several processes partly depending on crystal orientation during the various stages of an experiment. Initially, dissolution at the quartzite-sample surface occurs to saturate the fluid in the capsule with SiO2. Subsequently, grooving controlled by diffusion processes takes place parallel to dissolution and precipitation due to local differences in solubility. Finally, quench products develop on grain surfaces during the termination of experiments. The average groove-root angle amounts to about 160°, varying systematically with misorientation between neighboring grains and depending slightly on temperature and run duration. The grooving is thermally activated, i.e., groove depth ranging from 5 nm to several micrometers for the entire suite of experiments generally increases with temperature and/or run time. We use Mullins' classical theories to constrain kinetic parameters for the transport processes controlling the grooving. In the light of previous measurements of various diffusion coefficients in the system SiO2–H2O, interface diffusion of Si is identified as the most plausible rate-controlling process. Grooving could potentially proceed faster by diffusion through the liquid if the fluid were not convecting in the capsule. Characteristic times of healing of microfractures in hydrous environments constrained from these kinetic parameters are consistent with the order of magnitude of timescales over which postseismic healing occurs in situ according to geophysical surveys and recurrence intervals of earthquakes.

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Tomlinson, David H., Eric H. Christiansen, Jeffrey D. Keith, Michael J. Dorais, Rudy Ganske, Diego Fernandez, Nicholas Vetz, Mackenzie Sorensen, and Jens Gibbs. "Nature and Origin of Zoned Polymetallic (Pb-Zn-Cu-Ag-Au) Veins from the Bingham Canyon Porphyry Cu-Au-Mo Deposit, Utah." Economic Geology 116, no. 3 (May 1, 2021): 747–71. http://dx.doi.org/10.5382/econgeo.4798.

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Abstract Polymetallic veins (Pb-Zn-Cu-Ag-Au) at the world-class Bingham Canyon, Utah, porphyry Cu-Au-Mo deposit have long been recognized, but poorly understood. They are laterally zoned outward from the center of the porphyry deposit transitioning from Fe-Cu to Pb-Zn-Cu-Ag-Au mineralization. Physical and chemical characterization of these polymetallic veins provide insight into the origin, timing, and controls of ore deposition. These sheared, sulfide-rich, NE/SW- trending veins are dominated by pyrite and multiple generations of quartz, with lesser amounts of other sulfide and gangue minerals. Gold (0.27–4.61 ppm) provides the most value to the ore, though the veins contain substantial Cu and Ag as well. Host rocks include Eocene monzonite and Paleozoic limestone and quartzite—all of which can contain economic ore lodes. Associated alteration is predominantly sericitic and argillic, with mineralization in wall rocks restricted to 1.5 m from the vein margins. Mineral assemblages vary with distance from the center of the main porphyry Cu-Au-Mo deposit and the modal abundances are dependent on the host rock. The appearance of both galena and sphalerite (and tennantite to an extent) occur along a boundary that creates a halo around the center of the associated porphyry deposit. This is accompanied by a shift in metal ratios and an increased concentration of chalcophile trace elements in sulfides from the polymetallic veins as determined by electron microprobe analyses (EMPA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Significant hosts of Ag include galena and tennantite, and Cu is hosted primarily in chalcopyrite, tennantite, and sphalerite. The main host of Au could not be determined, but Au could be focused along fractures or hosted in inclusions found in pyrite. The δ34S values of vein pyrite have a narrow range (2.3–3.4‰) suggestive of a magmatic source, whereas δ18O of quartz is more variable (11.5–14.0‰). These values are similar to several other polymetallic vein deposits associated with porphyry Cu deposits. This can be explained by fractionation of magmatic fluids at lower temperatures (350°–250°C) and/or mixing with exchanged 18O-rich meteoric water. Ore grades (Cu, Ag, Au) improve with distance from the center of the porphyry deposit; however, this is accompanied by higher concentrations of deleterious elements (e.g., Pb, As, Bi) for downstream processing. These polymetallic veins were created sequentially throughout the formation of the deposit. Initial joints in the sedimentary rocks probably formed as a result of emplacement of a barren equigranular monzonite intrusion, with continued dilation and propagation in all host rocks with each subsequent intrusion. The northeast orientation of the joints was controlled by the regional stress field, which is more apparent distal to the center of the Bingham deposit. Vein mineralization appears to postdate all intrusions and the porphyry Cu-Au mineralization; however, it may be related to the late fluids responsible for Mo mineralization in the main porphyry orebody that followed intrusion of the quartz latite porphyry. Quartz-sericite-pyrite mineralization associated with the veins precedes galena-sphalerite-pyrite mineralization. This was followed by late precipitation of chalcopyrite and tennantite and late normal faulting.

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Lashko, Serhii. "Northeastern part of the Bilanivske ferruginousquartzite quarry: Risks of mining allotment." Mining of Mineral Deposits 15, no. 3 (September 2021): 54–61. http://dx.doi.org/10.33271/mining15.03.054.

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Purpose.Substantiation of the managerial decisions to minimize the risks of mining the Bilanivske ferruginous quartzite quarry on its northeastern margin. Methods. The legislative, methodological, cartographic and literary materials on the topic, as well as the area of survey have been analyzed. The necessary cartographic plotting and calculations have been performed. An abstract-logical method is used to formulate conclusions and theoretical generalizations. Findings. The ecological risks of the Bilanivske quarry northeastern margin have been substantiated: presence of uranium ore deposits and a radioactive anomaly; geochemical pollution of groundwater; a depression cone, large in area and in depth, can be formed in the region; a probability of using explosives when mining the field; use of the Bilanivske quarry eastern side for laying mine shafts and adits. The question is raised about the expected expansion of the Bilanivske quarry boundaries to the east during its mining, as well as falling into the sanitary protection zone boundaries of the northwestern residential community of the Nova Haleshchyna urban-type settlement. It is recommended, when mining the Bilanivske and Kremenchuk (Haleshchynske) iron ore deposits, to develop for them a unified draft Environmental Impact Assessment (EIA) and a unified draft of sanitary protection zone, taking into account the fact of their mutual influence on the environment. Originality.For the first time, based on a combination of geological, mining, technological and spatial factors, a site (zone) of mutual risks has been identified in the Bilanivske and Kremenchuk (Haleshchynske) iron ore deposits development. The site has an area of 165 ha, bounded by the northeastern side of the Bilanivske quarry and the southern boundary of the planned Haleshchynske mine. Practical implications.The research results can substantiate the need to resettle the residents from the northwestern residential community of the Nova Haleshchyna urban-type settlement, taking into account the Bilanivske field development by the open-pit method. In addition, they also can serve as a basis for resolving disputes between these residents and the administration of Ferrexpo Belanovo Mining LLC (Bilanivske Mining Plant).

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Ramesh Babu, Veldi, Indrajit Patra, Shailesh Tripathi, Sridhar Muthyala, and Anand K. Chaturvedi. "Inductive induced polarization effect in heliborne time-domain electromagnetic data for uranium exploration, northern part of Cuddapah Basin, India." GEOPHYSICS 82, no. 3 (May 1, 2017): B109—B120. http://dx.doi.org/10.1190/geo2016-0291.1.

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The Peddagattu, Lambapur, Chitrial and Koppunuru uranium deposits along the northern margins of the Cuddapah Basin are confined to the middle Proterozoic unconformity interface between Archean basement granites and the overlying resistive quartzites. Negative transients observed in the coincident loop heliborne time-domain electromagnetic (HTEM) data over these deposits (occurring in outliers) are believed to be due to thick polarizable conductive zones occurring along the unconformity. Similar negative HTEM responses are recorded over the Gorukunta Tanda outlier. A ground spectral induced polarization (SIP) survey conducted over the outlier and ground geologic observations indicated an altered basement/regolith with thickness up to 5 m below 20–30 m thick quartzite. Interpretation of Cole-Cole parameters computed from the SIP data indicated a change in the dispersion. These Cole-Cole parameters were used in modeling negative HTEM data assuming a polarizable plate placed in a layered earth at a depth of approximately 50 m using the CSIRO LeroiAir program. A negative [Formula: see text] response in the late channels indicated that the negatives can be explained in terms of inductive induced polarization effects. Modeling of HTEM [Formula: see text] data for the profile through the Lambapur uranium deposit and the Gorukunta Tanda reveals the presence of a polarizable lithologic unit at a depth of approximately 40 m. This unit is interpreted as an argillic alteration of basement, with the presence of clay and/or disseminated sulfides as evidenced from the core extracted from the boreholes at depths below the highly resistive quartzite. Uranium mineralization is closely associated with altered basement and sulfides along the unconformity where the distinct negative electromagnetic (EM) signature is recorded. Furthermore, there exists a good correlation between the uranium mineralization grade and the thickness versus the averaged late-channel negative HTEM response over the known deposits. The negative EM response helped in locating the new target areas for uranium exploration.

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HANNIGAN, R., and M. E. BROOKFIELD. "Inorganic geochemistry of the type Caradoc series (Sandbian to middle Katian, Upper Ordovician), Onny valley, Shropshire, UK." Geological Magazine 150, no. 4 (February 7, 2013): 699–727. http://dx.doi.org/10.1017/s0016756812000830.

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AbstractThe geochemistry and petrology of the type section of the Caradoc Series in the Onny valley indicate that it was deposited on a marginal basin continental shelf similar to the western side of the present Sea of Japan. The lower beds form a transgressive–regressive sequence in which the rocks become less mature upwards. All the coarser sediments above the basal quartzites and conglomerates are greywackes in which the apparent muddy and ferrous matrix is due to the breakdown of unstable minerals and particles. Higher values of Na2O and Na/K ratios are found in the coarser shallow-water sandstones of the Horderley Sandstone Formation and decrease markedly in the succeeding beds, accompanied by an increase in K2O. Higher values of carbonate-corrected (and hence related) other major and minor elements like SiO2, CaO, P2O5, MnO and most trace elements correlate with the transgressive systems and maximum flooding surfaces of the three sequences recognized where they are related to condensation at those horizons. Chemical Indices of Alteration (CIA) suggest that the Horderley Sandstone Formation underwent greater predepositional physical weathering than lower and higher beds, which is compatible with the petrography, and were deposited during a cool phase within overall warm Sandbian–Katian times. Trace element ratios suggest an oxic to suboxic depositional environment.

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Malehmir, Alireza, Bo Bergman, Benjamin Andersson, Robert Sturk, and Mattis Johansson. "Seismic imaging of dyke swarms within the Sorgenfrei–Tornquist Zone (Sweden) and implications for thermal energy storage." Solid Earth 9, no. 6 (December 14, 2018): 1469–85. http://dx.doi.org/10.5194/se-9-1469-2018.

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Abstract. There is a great interest and demand for green-type energy storage in Sweden for both short- and long-term (hours, days, weeks and seasons) periods. While there are a number of approaches proposed (e.g., compressed air, geothermal and thermal), only a few have commercially been demonstrated through upscaling projects. Among these, the thermal energy storage (TES) that stores energy (excess heat or cold) in fluids is particularly interesting. The excess energy can be stored underground in excavated caverns and used for large district heating and cooling purposes as well as for balancing and regulating electrical energy in power grids. For an upscaling underground TES project within the Tornquist suture zone of Scania in the southwest of Sweden, three high-resolution seismic profiles, each approximately 1 km long, were acquired. Geologically, the site sits within the southern margin of the Romeleåsen fault zone in the Sorgenfrei–Tornquist Zone (STZ), where dolerite dyke swarms of Carboniferous–Permian age are observed striking in the SE–NW direction for hundreds of kilometers both on land and in offshore seismic and magnetic data (from Scania to Midland Valley in the UK). These dykes, 10–50 m thick, in the nearby quarries (within both Precambrian gneiss and quartzite) express themselves mostly in a subvertical manner. They can therefore act as a good water/fluid barrier, which can be an important geological factor for any TES site. For the data acquisition, combined cabled and wireless recorders were used to provide continuity on both sides of a major road running in the middle of the study area. Bedrock depressions are clearly depicted in the tomograms, suggesting the possibility of zones of weaknesses, highly fractured and/or weathered, in the bedrock and confirmed in several places by follow-up boreholes. Several steeply dipping (60–65°) reflections were imaged down to 400 m depth and interpreted to originate from dolerite dykes. This interpretation is based on their orientations, strong amplitudes, regular occurrences and correlation with downhole logging data. In addition, groundwater flow measurements within the unconsolidated sediments and in bedrock suggest steeply dipping structures are the dominant factor in directing water mainly along a SE–NW trend, which is consistent with the strike of the dyke swarm within the STZ. To provide further insight on the origin of the reflections, even the historical crustal-scale offshore BABEL (Baltic and Bothnian Echoes from the Lithosphere) lines (A-AA-AB) were revisited. Clear multiphase faults and signs of intrusions or melt source in the lower crust are observed, as well as a Moho step across the Tornquist zone. Overall, we favor that the reflections are of dolerite origin and their dip component (i.e., not subvertical) may imply a Precambrian basement (and dykes) tilting, block rotation, towards the NE as a result of the Romeleåsen reverse faulting. In terms of thermal storage, these dykes then may be encountered during the excavation of the site and can complicate underground water flow should they be used as a fluid barrier in case of leakage.

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Borges, Gilliard Medeiros, Ronaldo Pierosan, and Rubia Ribeiro Viana. "Geologia e petrologia dos gnaisses da região de São Valério da Natividade, Tocantins." Geologia USP. Série Científica 19, no. 2 (June 13, 2019): 41–66. http://dx.doi.org/10.11606/issn.2316-9095.v19-146664.

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A região de São Valério da Natividade no estado de Tocantins está relacionada ao Maciço de Goiás e ao Bloco Cavalcante-Natividade, compondo embasamento da Faixa Brasília, constituída dominantemente de complexos gnáissicos migmatíticos paleoproterozoicos ortoderivados de composição granodiorítica a tonalítica. Localmente, ocorrem lentes de xistos metapelíticos, com porfiroblastos de granada e estaurolita, e quartzitos. Os gnaisses ortoderivados apresentam um bandamento contínuo com orientação NE-SW e mergulhos subverticais, enquanto os migmatitos são representados por metatexitos formados em regime compressional e sob influência de zonas de cisalhamento. A xistosidade dos metapelitos é paralela à dos gnaisses e sua associação mineralógica registra um pico metamórfico da fácies anfibolito superior com retrometamorfismo da fácies xisto verde. Com base nas foliações internas dos porfiroblastos de estaurolita dos metapelitos foi possível identificar duas fases de deformação dúctil. A terceira fase é marcada pela xistosidade dos metapelitos e pelo bandamento gnáissico. Uma quarta fase de deformação, de caráter rúptil, também pode ser observada. A composição química dos gnaisses ortoderivados sugere protólito granodiorítico, com características de suítes tonalitotrondhjemito-granodiorito (TTG) calcioalcalinas, contribuição de fusão parcial de fontes tipo MORB, no bloco crustal Cavalcante-Natividade e retrabalhamento crustal nos gnaisses do Maciço de Goiás. Os dados geocronológicos U-Pb de gnaisse ortoderivado em diagrama concórdia apresentam um intercepto superior de 2229 ± 13 Ma, interpretado como idade do protólito, e um intercepto inferior de 614 ± 85 Ma, interpretado como a idade do metamorfismo mais jovem. Idades de cristalização semelhantes foram obtidas para o Domínio Almas-Conceição do Tocantins, também relacionadas a suítes TTGs calcioalcalinas (Suíte Manoel Alves). A idade do metamorfismo é compatível com as idades estimadas para o Ciclo Brasiliano-Pan Africano na

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Selverstone, J., and J. Hyatt. "Chemical and physical responses to deformation in micaceous quartzites from the Tauern Window, Eastern Alps." Journal of Metamorphic Geology 21, no. 4 (April 29, 2003): 335–45. http://dx.doi.org/10.1046/j.1525-1314.2003.00444.x.

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Das, Swapan Kr, Kausik Dana, Nar Singh, and Ritwik Sarkar. "Shrinkage and strength behaviour of quartzitic and kaolinitic clays in wall tile compositions." Applied Clay Science 29, no. 2 (April 2005): 137–43. http://dx.doi.org/10.1016/j.clay.2004.10.002.

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Zhang, Hong-Fu, Jing-Li Wang, Ding-Wu Zhou, Yue-Heng Yang, Guo-Wei Zhang, M. Santosh, Hong Yu, and Juan Zhang. "Hadean to Neoarchean episodic crustal growth: Detrital zircon records in Paleoproterozoic quartzites from the southern North China Craton." Precambrian Research 254 (November 2014): 245–57. http://dx.doi.org/10.1016/j.precamres.2014.09.003.

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36

Craddock, John P., and Alexander W. McKiernan. "Tectonic implications of finite strain variations in Baraboo-interval quartzites (ca. 1700Ma), Mazatzal orogen, Wisconsin and Minnesota, USA." Precambrian Research 156, no. 3-4 (June 2007): 175–94. http://dx.doi.org/10.1016/j.precamres.2006.03.010.

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Porter, E. W., and W. C. James. "Influence of pressure, salinity, temperature and grain size on silica diagenesis in quartzose sandstones." Chemical Geology 57, no. 3-4 (December 1986): 359–69. http://dx.doi.org/10.1016/0009-2541(86)90058-6.

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Lima, Rosa Malena Fernandes, Alexandro Fortes Simões da Silva, Rubhia Marianna Maciel de Morais, and José Aurélio Medeiros da Luz. "Caracterização tecnológica de resíduos de pedreiras de quartzito da região de Ouro Preto/MG." Rem: Revista Escola de Minas 60, no. 4 (December 2007): 663–68. http://dx.doi.org/10.1590/s0370-44672007000400012.

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Os quartzitos da serra do Taquaral em Ouro Preto-MG são extraídos para serem usados como placa de pisos e revestimentos. Pelo fato dE a rocha ser bastante intemperizada e, por essa razão, ser friável, são geradas, nas frentes de lavra e no beneficiamento, um grande volume de resíduos de ampla distribuição granulométrica. Por essa razão, esse trabalho teve, por objetivo, caracterizar as areias provenientes das frentes de lavra dessas pedreiras, que são, normalmente, depositadas nas encostas dos morros. Através dos estudos realizados com três amostras, verificou-se a viabilidade técnica de utilização das mesmas na construção civil, na fundição e, após purificação por separação magnética de alta intensidade e flotação dos minerais portadores dos elementos químicos deletérios (F2O3, Al2O3 e TiO2), vislumbra-se a possibilidade do uso dessas areias na indústria de vidro, o que é extremamente importante do ponto de vista social, econômico e ambiental.

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Kronenberg, Andreas K., Hasnor F. B. Hasnan, Caleb W. Holyoke III, Richard D. Law, Zhenxian Liu, and Jay B. Thomas. "Synchrotron FTIR imaging of OH in quartz mylonites." Solid Earth 8, no. 5 (October 4, 2017): 1025–45. http://dx.doi.org/10.5194/se-8-1025-2017.

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Abstract. Previous measurements of water in deformed quartzites using conventional Fourier transform infrared spectroscopy (FTIR) instruments have shown that water contents of larger grains vary from one grain to another. However, the non-equilibrium variations in water content between neighboring grains and within quartz grains cannot be interrogated further without greater measurement resolution, nor can water contents be measured in finely recrystallized grains without including absorption bands due to fluid inclusions, films, and secondary minerals at grain boundaries.Synchrotron infrared (IR) radiation coupled to a FTIR spectrometer has allowed us to distinguish and measure OH bands due to fluid inclusions, hydrogen point defects, and secondary hydrous mineral inclusions through an aperture of 10 µm for specimens > 40 µm thick. Doubly polished infrared (IR) plates can be prepared with thicknesses down to 4–8 µm, but measurement of small OH bands is currently limited by strong interference fringes for samples < 25 µm thick, precluding measurements of water within individual, finely recrystallized grains. By translating specimens under the 10 µm IR beam by steps of 10 to 50 µm, using a software-controlled x − y stage, spectra have been collected over specimen areas of nearly 4.5 mm2. This technique allowed us to separate and quantify broad OH bands due to fluid inclusions in quartz and OH bands due to micas and map their distributions in quartzites from the Moine Thrust (Scotland) and Main Central Thrust (Himalayas).Mylonitic quartzites deformed under greenschist facies conditions in the footwall to the Moine Thrust (MT) exhibit a large and variable 3400 cm−1 OH absorption band due to molecular water, and maps of water content corresponding to fluid inclusions show that inclusion densities correlate with deformation and recrystallization microstructures. Quartz grains of mylonitic orthogneisses and paragneisses deformed under amphibolite conditions in the hanging wall to the Main Central Thrust (MCT) exhibit smaller broad OH bands, and spectra are dominated by sharp bands at 3595 to 3379 cm−1 due to hydrogen point defects that appear to have uniform, equilibrium concentrations in the driest samples. The broad OH band at 3400 cm−1 in these rocks is much less common. The variable water concentrations of MT quartzites and lack of detectable water in highly sheared MCT mylonites challenge our understanding of quartz rheology. However, where water absorption bands can be detected and compared with deformation microstructures, OH concentration maps provide information on the histories of deformation and recovery, evidence for the introduction and loss of fluid inclusions, and water weakening processes.

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Watson, Ken, Lawrence C. Rowan, Timothy L. Bowers, Carmen Anton‐Pacheco, Pablo Gumiel, and Susanne H. Miller. "Lithologic analysis from multispectral thermal infrared data of the alkalic rock complex at Iron Hill, Colorado." GEOPHYSICS 61, no. 3 (May 1996): 706–21. http://dx.doi.org/10.1190/1.1443998.

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Airborne thermal‐infrared multispectral scanner (TIMS) data of the Iron Hill carbonatite‐alkalic igneous rock complex in south‐central Colorado are analyzed using a new spectral emissivity ratio algorithm and confirmed by field examination using existing 1:24 000‐scale geologic maps and petrographic studies. Color composite images show that the alkalic rocks could be clearly identified and that differences existed among alkalic rocks in several parts of the complex. An unsupervised classification algorithm defines four alkalic rock classes within the complex: biotitic pyroxenite, uncompahgrite, augitic pyroxenite, and fenite + nepheline syenite. Felsic rock classes defined in the surrounding country rock are an extensive class consisting of tuff, granite, and felsite, a less extensive class of granite and felsite, and quartzite. The general composition of the classes can be determined from comparisons of the TIMS spectra with laboratory spectra. Carbonatite rocks are not classified, and we attribute that to the fact that dolomite, the predominant carbonate mineral in the complex, has a spectral feature that falls between TIMS channels 5 and 6. Mineralogical variability in the fenitized granite contributed to the nonuniform pattern of the fenite‐nepheline syenite class. The biotitic pyroxenite, which resulted from alteration of the pyroxenite, is spatially associated and appears to be related to narrow carbonatite dikes and sills. Results from a linear unmixing algorithm suggest that the detected spatial extent of the two mixed felsic rock classes was sensitive to the amount of vegetation cover. These results illustrate that spectral thermal infrared data can be processed to yield compositional information that can be a cost‐effective tool to target mineral exploration, particularly in igneous terranes.

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Lana, Cláudio Eduardo, and Paulo de Tarso Amorim Castro. "Análise sedimentológica e de proveniência de sedimentos fluviais nas cabeceiras do rio das Velhas, município de Ouro Preto, MG." Rem: Revista Escola de Minas 61, no. 1 (March 2008): 63–68. http://dx.doi.org/10.1590/s0370-44672008000100011.

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Esse trabalho apresenta os resultados do estudo sedimentológico em um segmento fluvial do alto rio das Velhas, na região de Ouro Preto, Minas Gerais. Os sedimentos foram coletados em duas barras e duas séries de transectos distribuídos ao longo do canal. A granulometria, mineralogia/petrografia e o grau de arredondamento dos clastos foram analisados. Os resultados indicaram que o segmento fluvial pode ser classificado como um ambiente cascalhoso, com predominância de clastos subangulosos a subarredondados de quartzo, hematita, metadiabásio, canga e quartzito. Esses dados indicam uma contribuição associada a veios de quartzo, às formações ferríferas do Grupo Itabira, às rochas do Grupo Caraça e a pequenos corpos máficos intrusivos.

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42

Craddock, John P., and Alexander W. McKiernan. "Erratum to “Tectonic implications of finite strain variations in Baraboo-interval quartzites (ca. 1700 Ma), Mazatzal orogen, Wisconsin and Minnesota, USA” [Precambrian Res. 156 (2007) 175–194]." Precambrian Research 157, no. 1-4 (August 2007): 214. http://dx.doi.org/10.1016/j.precamres.2007.06.003.

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43

Migaszewski, Zdzisław, Ewa Starnawska, and Agnieszka Gałuszka. "Gorceixite from the Upper Cambrian Rocks of the podwiśniówka Mine Pit, Holy Cross Mountains (South-Central Poland)." Mineralogia 38, no. 2 (January 1, 2007): 171–84. http://dx.doi.org/10.2478/v10002-007-0025-6.

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Gorceixite from the Upper Cambrian Rocks of the podwiśniówka Mine Pit, Holy Cross Mountains (South-Central Poland)This report presents the results of a petrographical, mineralogical (SEM/EDS, XRD) and geochemical (XRF, CV-AAS, ICP-MS) study of gorceixite (barium aluminophosphate) from the abandoned Podwiśniówka mine pit. This site is highlighted by the presence of highly acidic pit pond whose chemistry is strongly affected by the exposed pyrite-bearing zone. The gorceixite occurs in the Upper Cambrian carbonaceous clayey shales, quartzites and tuffs in form of minute accumulations varying from about 0.5 to 100 μm in diameter. These accumulations infill voids, cavities, cracks and partly fissures in the rocks examined. The other minerals of the crandallite series, i.e. florencite and goyazite, can be found only in trace amounts. The gorceixite-bearing rocks, especially carbonaceous clayey shales, are characterized by the highest concentrations of REE reaching 455.09 mg·kg-1. In addition, these rocks are distinctly enriched in light rare earth elements (LREE), with the La/Yb ratio ranging from 24.44 through 36.30. Some of the examined gorceixite accumulations are paragenetically linked to the veined pyrite and nacrite. The latter mineral is indicative of crystallization temperatures of about 200 to 300°C. The coexistence of gorceixite with the veined nacrite or pyrite mineralization and the volcaniclastic rocks, as well as the microtextural features and high concentrations of REE in the gorceixite-bearing parent rocks suggest that this mineral formed as a result of both hydrothermal and volcanic activity in a shallow-marine basin during the late Cambrian.

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Mochnacka, Ksenia, Teresa Oberc-Dziedzic, Wojciech Mayer, and Adam Pieczka. "Ore mineralization in the Miedzianka area (Karkonosze-Izera Massif, the Sudetes, Poland): new information." Mineralogia Polonica 43, no. 3-4 (December 1, 2012): 155–78. http://dx.doi.org/10.2478/v10002-012-0005-3.

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AbstractThe Miedzianka mining district has been known for ages as a site of polymetallic ore deposits with copper and, later, uranium as the main commodities. Although recently uneconomic and hardly accessible, the Miedzianka ores attract Earth scientists due to the interesting and still controversial details of their ore structure, mineralogy and origin. Our examination of the ore mineralization from the Miedzianka district was based exclusively on samples collected from old mining dumps located in the vicinity of Miedzianka and Ciechanowice, and on samples from the only available outcrop in Przybkowice. In samples from the Miedzianka field, chalcopyrite, pyrite, galena, bornite, chalcocite, digenite, arsenopyrite, magnetite, sphalerite, tetrahedrite-tennantite, bornite, hematite, martite, pyrrhotite, ilmenite, cassiterite and covellite are hosted in quartz-mica schists and in coarse-grained quartz with chlorite. In the Ciechanowice field, the ore mineralization occurs mainly in strongly chloritized amphibolites occasionally intergrown with quartz and, rarely, with carbonates. Other host-rocks are quartz-chlorite schist and quartzites. Microscopic examination revealed the presence of chalcopyrite, pyrite, sphalerite, galena, tetrahedrite-tennantite, bismuthinite, native Bi, arsenopyrite, löllingite, cassiterite, cobaltite, gersdorffite, chalcocite, cassiterite, bornite, covellite, marcasite and pyrrhotite. Moreover, mawsonite and wittichenite were identified for the first time in the district. In barite veins cross-cutting the greenstones and greenschists in Przybkowice, we found previously-known chalcopyrite, chalcocite and galena. The composition of the hydrothermal fluids is suggested to evolved through a series of consecutive systems characterized, in turn, by Ti-Fe-Sn, Fe- As-S, Fe-Co-As-S, Cu-Zn-S and, finally, Cu-Pb-Sb-As-Bi compositions.

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Mishin, L. F. "Secondary quartzites and their relation to gold mineralization at the Svetloe deposit, Ul’ya Trough, Okhotsk-Chukotka volcanic belt." Russian Journal of Pacific Geology 5, no. 4 (August 2011): 298–312. http://dx.doi.org/10.1134/s1819714011040063.

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46

Pérez-Aguilar, Annabel, Setembrino Petri, Rafhael Hypólito, Sibele Ezaki, Paulo Alves de Souza, Caetano Juliani, Lena V. S. Monteiro, and Francisco A. Moschini. "Superfícies estriadas no embasamento granítico e vestígio de pavimento de clastos neopaleozóicos na região de Salto, SP." Rem: Revista Escola de Minas 62, no. 1 (March 2009): 17–22. http://dx.doi.org/10.1590/s0370-44672009000100004.

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Nas proximidades da Cerâmica Guaraú, localizada a sudoeste da cidade de Salto, Estado de São Paulo, dois afloramentos de granito, distantes algumas dezenas de metros um do outro, exibem superfícies estriadas neopaleozóicas. Essas superfícies estão em contato com diamictitos do Subgrupo Itararé. As estrias correspondem a sulcos subparalelos com espaçamento e profundidade milimétrica, possuindo uma direção média de N48°W e mergulhos variando entre 12° e 42° para SE. As feições observadas e a sua associação com diamictitos indicam uma origem por abrasão glacial devido ao movimento de massas de gelo de sudeste para noroeste. A aproximadamente 1,8 km a este da cidade de Salto foi encontrado, no topo de afloramentos de granito, material inconsolidado contendo abundantes clastos de quartzito facetados e estriados. Esses clastos foram interpretados como vestígios de um pavimento de castos.

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Chaves, Mario Luiz de Sá C., Joachim Karfunkel, and Miguel Tupinambá. "Estruturação "em rosário" dos depósitos de quartzo hidrotermal do Morro do Juá (Gouveia, MG)." Rem: Revista Escola de Minas 56, no. 1 (March 2003): 15–20. http://dx.doi.org/10.1590/s0370-44672003000100004.

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Veios de quartzo hidrotermal ocorrem na área a oeste do Morro do Juá (Gouveia-MG), definindo uma forma típica "em rosário", controlada pela estratigrafia e estruturas da área. Os veios, normalmente zonados, ocorrem em quartzitos grossos da Formação São João da Chapada (Supergrupo Espinhaço), que sobrepõem xistos do Supergrupo Rio Paraúna e são capeados por metabasitos. Apresentam atitudes preferenciais com pólos centralizados em N05ºE/73ºNW e N18ºE/74ºSE, os quais indicam, respectivamente, suas prováveis direções de condução e alojamento. A gênese desses veios condiciona-se à formação de zonas de cisalhamento durante o Ciclo Brasiliano.

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Zeh, Armin, Axel Gerdes, Jay Barton, and Reiner Klemd. "U–Th–Pb and Lu–Hf systematics of zircon from TTG's, leucosomes, meta-anorthosites and quartzites of the Limpopo Belt (South Africa): Constraints for the formation, recycling and metamorphism of Palaeoarchaean crust." Precambrian Research 179, no. 1-4 (May 2010): 50–68. http://dx.doi.org/10.1016/j.precamres.2010.02.012.

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Ferreira, Gilda Carneiro, and Elias Carneiro Daitx. "A mineração de areia industrial na Região Sul do Brasil." Rem: Revista Escola de Minas 56, no. 1 (March 2003): 59–65. http://dx.doi.org/10.1590/s0370-44672003000100011.

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Na Região Sul do Brasil existem atualmente dez empresas de mineração produzindo areia industrial a partir do beneficiamento de areia quartzosa, de quartzito e de arenito, utilizando processos de seleção granulométrica e mineralógica e agregando valor a esses bens minerais. O Estado de Santa Catarina é o maior produtor de areia industrial da Região Sul, com destaque para a região de Araquari, onde são lavrados sedimentos quaternários litorâneos, abastecendo principalmente a maior fundição da América Latina, localizada em Joinville. As minas situadas nos Estados do Paraná, em Campo Largo, e do Rio Grande do Sul, em Viamão, abastecem com prioridade as indústrias de cerâmica e de vidro, respectivamente. Esse expressivo mercado consumidor tem atraído a atenção da maior mineradora de areia industrial do país, com jazidas situadas em São Paulo, a qual tem buscado alternativas para a instalação de novas minas nos Estados do Paraná e de Santa Catarina.

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50

Griscom, D. L. "In plain sight: the Chesapeake Bay crater ejecta blanket." Solid Earth Discussions 4, no. 1 (February 14, 2012): 363–428. http://dx.doi.org/10.5194/sed-4-363-2012.

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Abstract. The discovery nearly two decades ago of a 90 km-diameter impact crater below the lower Chesapeake Bay has gone unnoted by the general public because to date all published literature on the subject has described it as "buried". To the contrary, evidence is presented here that the so-called "upland deposits" that blanket ∼5000 km2 of the U.S. Middle-Atlantic Coastal Plain (M-ACP) display morphologic, lithologic, and stratigraphic features consistent with their being ejecta from the 35.4 Ma Chesapeake Bay Impact Structure (CBIS) and absolutely inconsistent with the prevailing belief that they are of fluvial origin. Specifically supporting impact origin are the facts that (i) a 95 %-pure iron ore endemic to the upland deposits of southern Maryland, eastern Virginia, and the District of Columbia has previously been proven to be impactoclastic in origin, (ii) this iron ore welds together a small percentage of well-rounded quartzite pebbles and cobbles of the upland deposits into brittle sheets interpretable as "spall plates" created in the interference-zone of the CBIS impact, (iii) the predominantly non-welded upland gravels have long ago been shown to be size sorted with an extreme crater-centric gradient far too large to have been the work of rivers, but well explained as atmospheric size-sorted interference-zone ejecta, (iv) new evidence is provided here that ~60 % of the non-welded quartzite pebbles and cobbles of the (lower lying) gravel member of the upland deposits display planar fractures attributable to interference-zone tensile waves, (v) the (overlying) loam member of the upland deposits is attributable to base-surge-type deposition, (vi) several exotic clasts found in a debris flow topographically below the upland deposits can only be explained as jetting-phase crater ejecta, and (vii) an allogenic granite boulder found among the upland deposits is deduced to have been launched into space and sculpted by hypervelocity air friction during reentry. An idealized calculation of the CBIS ejecta-blanket elevation profile minutes after the impact was carried out founded on well established rules for explosion and impact-generated craters. This profile is shown here to match the volume of the upland deposits ≥170 km from the crater center. Closer to the crater, much of the "postdicted" ejecta blanket has clearly been removed by erosion. Nevertheless the Shirley and fossil-free Bacons Castle Formations, located between the upland deposits and the CBIS interior and veneering the present day surface with units ∼10–20 m deep, are respectively identified as curtain- and excavation-phase ejecta. The neritic-fossil-bearing Calvert Formation external to the crater is deduced to be of Eocene age (as opposed to early Miocene as currently believed), preserved by the armoring effects of the overlying CBIS ejecta composed of the (distal) upland deposits and the (proximal) Bacons Castle Formation. The lithofacies of the in-crater Calvert Formation can only have resulted from inward mass wasting of the postdicted ejecta blanket, vestiges of which (i.e. the Bacons Castle and Shirley Formations) still overlap the crater rim and sag into its interior, consistent with this expectation. Because there appear to be a total of ∼10 000 km2 of CBIS ejecta lying on the present-day surface, future research should center the stratigraphic, lithologic, and petrologic properties of these ejecta versus both radial distance from the crater center (to identify ejecta from different ejection stages) and circumferentially at fixed radial distances (to detect possible anisotropies relating the impact angle and direction of approach of the impactor). The geological units described here may comprise the best preserved, and certainly the most accessible, ejecta blanket of a major crater on the Earth's surface and therefore promise to be a boon to the field of impact geology. As a corollary, a major revision of the current stratigraphic column of the M-ACP will be necessary.

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Journal articles on the topic 'Quartzite. Petrology Geology'

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