Journal articles: 'Ultrabasite'

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Tovstyuk, Zinaida, and Tetiana Yefimenko. "Morphostructural investigation within the Orihovo-Pavlograd zone." Ukrainian journal of remote sensing, no. 19 (December 31, 2018): 30–33. http://dx.doi.org/10.36023/ujrs.2018.19.140.

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This detailed investigation was conducted for the South part of the Orikhovo-Pavlograd suture zone by using satellite imagery. At the first stage, the imagery was used to extract lineaments and arcuate relief elements. Further, geomorphological anomalies were highlighted by means of structural and geomorphological analysis of the study area. The significant number of ultrabasite bodies were distinguished alongside the entire Orikhovo-Pavlograd suture zone with allowance for the geological structure. The sites of kimberlite magmatism defined according to geophysical investigations can be associated with ultrabasite bodies. Prognostic sites of kimberlite magmatism were allocated and complex of morphostructural geoindication features were educed above the prognostic paleo-volcano that had erupted ultrabasites. The geoindicators of morphostructures are: the spreading and narrowing of a floodplain; displacement of a stream bed; deeping of the stream bed plunging depth; straightened reach of the stream bed; discordant course of the left tributaries of the Molochna river; augmentation of the stream bed meandering; floodplain marshy parts at the beginning of morphostructures; intense developing of a ravine-gully network on the right side of the Molochna river; localization of sand massifs on the anomalously located second terrace of the Molochna river flood-plain; rills and numerous artesian wells within the floodplain. These indicators have made it possible to construct a geoindication scheme, distinguish the prognostic Melitopol morphostructure and make a prognosis for mineral exploration. The formation of this morphological structure can be ascribed with a paleo-volcano, which igneous rocks are ultrabasites and kimberlites. Rocks of these complexes can be prospective evidence for diamond, iron, nickel, copper, lead and zinc deposits exploration. Hydrothermal and metasomatic sulphide (polymetallic) mineral occurrences can be explored as well. The procedure of geoindication investigation will be applied for integrated exploration throughout the entire area of the Orekhovo-Pavlograd suture zone.

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KISIN, Aleksandr Yur’evich, Valeriy Vasil’evich MURZIN, Elizaveta Sergeevna KARASEVA, Vitaliy Nikolaevich OGORODNIKOV, Yuriy Alekseevich POLENOV, Sergey Gennad’evich SELEZNEV, and Danil Aleksandrovich OZORNIN. "Issues of structural control of demantoid mineralization at the Poldnevskoye deposit (Middle Urals)." NEWS of the Ural State Mining University 1, no. 2 (June 15, 2020): 64–73. http://dx.doi.org/10.21440/2307-2091-2020-2-64-73.

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Relevance of the work is due to the need to establish structural control of the mineralization of jewelry demantoid in ultrabasites of the Korkodinsky massif for forecasting, prospecting and exploration of its deposits. Purpose of the work: identification the criteria for structural control at the Poldnevsky demantoid field. Research methodology: analysis of literature data on research topics, studying the geology of the field and the nature of the distribution of mineralization, the conditions of occurrence of mineralized zones, the features of fault tectonics in the quarry of the Poldnevskoye field, the study of thin sections and thin sections by optical methods Results. A geotectonic model for the formation of the Korkodinsky ultrabasite massif represented by a crust-mantle mixture from the depth of 50–60 km is proposed. In the process of rock hoisting, decompression, metamorphism and hydrothermal-metasomatic transformations, decompression fracturing were experienced. The earliest fractures were made by hydrothermal-metasomatic clinopyroxenite, which then also underwent decompression fracturing. Ultrabasic rocks and clinopyroxenites underwent local antigoritization. Later decompression fractures are made by antigorite, clinochrysotile, carbonate, sometimes magnetite and demantoid. All of them were formed under conditions of continuous decrease in allround pressure and synchronous opening of decompression fractures. The largest fractures are oriented subparallel to the wings of the enclosing fault and have a steep fall. The fractures are sinuous and can be arranged en echelon. Mineral-forming fluids were released from the massif as a result of decompression and mixed with meteoric waters penetrating along tensile cracks in the roof of the massif. Late low-temperature serpentinization of the massif is accompanied by the manifestation of “serpentinite tectonics”, which can destroy bunches with demantoid mineralization when superimposition. The demantoid mineralization in weakly serpentinized dunites is preserved from destruction by “serpentinite tectonics”. Conclusion. Since demantoid mineralization is confined to decompression fractures, the possibilities of structural control are very limited. The largest fractures are oriented subconcordantly to the sides of the fault enclosing the massif. This pattern of the distribution of demantoid mineralization in ultrabasites is favorable for the formation of deluvial-alluvial placers, but is unfavorable for development in bedrock depth.

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Appel, C. C., P. W. U. Appel, and H. R. Rollinson. "Complex chromite textures reveal the history of an early Archaean layered ultramafic body in West Greenland." Mineralogical Magazine 66, no. 6 (December 2002): 1029–41. http://dx.doi.org/10.1180/0026461026660075.

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Abstract Massive chromitite, banded chromitite and disseminated chromite grains are found in a ˜3800 Ma layered ultrabasic body in West Greenland. The major part of the ultrabasite is dominated by dunite. In the upper exposed part, harzburgite and sheets of gabbro-anorthosite occur. Chromite grains in dunites, and in massive and banded chromitites are homogeneous, with increasing Fe contents upwards in the intrusion. In harzburgites chromites show unusual and very complex textural relationships, with two generations ofchromites one replacing the other, and both exhibiting exsolution textures. In harzburgites, an Fe-rich chromite crystallized first. This first chromite exsolved two spinel phases in a very fine-scale pattern and ilmenite lamellae in a trellis pattern. The Fe-rich chromite was later partly replaced by Al-rich chromite, which crystallized contemporaneously with formation of a late gabbro-anorthositic melt. Subsequently, the Al-rich chromite exsolved a very fine-scale magnetite-rich phase. The exsolutions in the first generation chromite were formed under magmatic conditions. Exsolution of ilmenite lamellae in Fe-rich spinel was caused by oxidation under magmatic conditions.

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Khanchuk, A. I., and S. V. Vysotskiy. "Different-depth gabbro–ultrabasite associations in the Sikhote-Alin ophiolites (Russian Far East)." Russian Geology and Geophysics 57, no. 1 (January 2016): 141–54. http://dx.doi.org/10.1016/j.rgg.2016.01.010.

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Khanchuk, A. I., and S. V. Vysotskiy. "DIFFERENT-DEPTH GABBRO-ULTRABASITE ASSOCIATIONS IN THE SIKHOTE-ALIN OPHIOLITES (Russian Far East)." Геология и геофизика 57, no. 1 (2016): 181–98. http://dx.doi.org/10.15372/gig201601010.

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Bochevar, R. O. "FORMATION ACCESSORY AND CREATION STAGES OF ORE OF ULTRABASITE MASSIVES OF THE KAPITANIVSKE ORE FIELD." Collection of Scientific Works of the Institute of Geological Sciences of the NAS of Ukraine 4 (March 11, 2011): 28–34. http://dx.doi.org/10.30836/igs.2522-9753.2011.152636.

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Khanchuk, A. I., V. P. Molchanov, and D. V. Androsov. "First Finds of Native Gold and Platinum in the Ilmenite Placers of the Ariadnoye Basite–Ultrabasite Intrusion (Primorye)." Doklady Earth Sciences 492, no. 2 (June 2020): 422–25. http://dx.doi.org/10.1134/s1028334x20060070.

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KREMENETSKIY, Alexander. "A new formation model of the Atlantic-Arctic heterochronous rifting system: A concept and basic provisions." Domestic geology, no. 3-4 (September 14, 2021): 18–27. http://dx.doi.org/10.47765/0869-7175-2021-10018.

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A new formation model of the global Atlantic-Arctic heterochronous rifting system is substantiated, according to which the Central and North Atlantics, Labrador-Baffin seas, and Arctic Ocean represent morpho-tectonic elements of different orders of the united recent Atlantic-Arctic Ocean. Evolution of the global rift system of this ocean includes three stages: the first stage (D–J1) was expressed by establishment of a tectonic zone in the lithosphere of Pangea with formation of the ophiolite ultrabasite-gabbro association; the second stage (J1–₽1) represented stretching of the continental crust to form depressions and uplifts with areal manifestation of trap magmatism of Cretaceous and other ages; and the third one (₽2–present) is neotectonic-magmatic reactivation with formation of a middle ridge, that is being accompanied by outpouring of glassy basalts and by hydrothermal manifestations. Within the framework of this model, the history of formation is reconstructed of the Eurasian Basin and the Gakkel Ridge, that were included in the Russia's updated application for expansion of the outer continental shelf border.

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Ilic, Miloje, Zoran Pavlovic, and Zoran Miladinovic. "Magnesite-bearing fracture zones of the Zlatibor ultrabasic massif (Serbia) as a discrete structural-morphological type of magnesite deposits in ultrabasites." Annales g?ologiques de la Peninsule balkanique, no. 72 (2011): 111–17. http://dx.doi.org/10.2298/gabp1172111i.

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In this paper, a discrete structural-morphological type of magnesite deposits in ultrabasites, i.e., in magnesite-bearing fracture zones, is presented. The most prominent occurrences of such zones in Serbia are in the Zlatibor ultrabasic massif and they are economically very significant because they contain large reserves of high-quality magnesite, as well as of the accompanying sepiolite.

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Andronikov, A. V. "Spinel-garnet Iherzolite nodules from alkaline-ultrabasic rocks of Jetty Peninsula (East Antarctica)." Antarctic Science 2, no. 4 (December 1990): 321–30. http://dx.doi.org/10.1017/s0954102090000451.

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The petrography and mineralogy of Iherzolite nodules from an intrusive body of alkaline-ultrabasic rocks on Jetty Peninsula. The nodules are massive with a porphyritic hypidiomorphic granular texture. The main rock-forming minerals are: olivine, pyroxene, garnet and chrome spinel. The nodules are coarse granular spinel-garnet Iherzolites that are chemically similar to pyrope peridotite from Krezemze, Czechoslovakia, and pyrope-bearing peridotite from alkaline ultrabasites of Yakutia, USSR. The Al2O3 content in enstaties and Ca/(Ca + Mg) ratio in co-existing chrome diopside suggest that equilibrium conditions of the mantle mineral assemblage are: T = 875–900°C, P = 20–24 kbar, conditions typical of the spinel-pyrope facies of the upper mantle. Depths of withdrawal of the inclusions do not exceed 60–75 km. Available age determinations of the intrusive alkaline-ultrabasic rocks (145–150 Ma) suggest that alkaline-ultrabasic magmatism and withdrawal of plutonic nodules were related to rifting which resulted in the breakup of the Gondwana supercontinent in the late Mesozoic.

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Logachev, P. V., Yu I. Semenov, V. N. Sharapov, A. E. Boguslavskii, and N. M. Podgornykh. "Some Structural and Mineralogical Peculiarities of Quenching Liquids Obtained by Melting of Mantle Ultrabasite Xenoliths and Mafic Volcanics by an Electron Beam." Doklady Earth Sciences 481, no. 2 (August 2018): 1095–98. http://dx.doi.org/10.1134/s1028334x18080317.

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12

Ilalova, R. K., A. M. Duryagina, and A. S. Ageev. "Minerogenesis sequence and processes in weathering mantle of ultrabasitic rocks of the Serov-Mauk ophiolite belt (Northern Urals)." Mining informational and analytical bulletin, no. 7 (June 20, 2020): 13–26. http://dx.doi.org/10.25018/0236-1493-2020-7-0-13-26.

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The geological structure and mineral composition in weathering mantle of ultrabasitic formations of the Serov-Mauk ophiolite belt are comprehensively studied. Considering complex geological history of the weathering mantle, the studies involved a wide range of precision research methods-optical microscopy, X-ray diffraction analysis, thermal tests, Xray microspectral analysis and Raman spectrography. As a result, the minerogenesis sequence was disclosed, and the modern genetic classification of minerals in ultrabasites and weathering mantle was developed. The classification distinguishes between hypogene and supergene minerals in weathering mantle of ultrabasitic rocks of the Serov-Mauk ophiolite belt. Hypogene minerals are divided into four groups-magmagene-relict, oceanic waste minerals, low-grade metamorphogenic-relict and hydrothermal relict minerals. Supergene minerals are grouped into residuum and rocks superimposed in infiltration. Residuum is divided into two groups of diffusion and infiltration minerals. The research findings revel the critical geological processes connected with evolution of ultrabasitic formations and weathering mantle of the Serov-Mauk ophiolite belt. The drawn conclusions prove hydrothermal processes and low-grade metamorphism in the history of rock mass and weathering mantle of the Serov-Mauk ophiolite belt, and can be used for the prognostics and prospecting of nickel ore bodies.

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Kozakov, I. K., D. A. Lykhin, Ch Erdenegargal, E. B. Salnikova, I. V. Anisimova, V. P. Kovach, Yu V. Plotkina, and A. M. Fedoseenko. "Tectonic Position of the Neoproterozoic Gabbro-Ultrabasite and Gabbroid Complexes of the Bayan Nuur Block of the Songino Ledge, Central Asian Orogenic Belt." Stratigraphy and Geological Correlation 27, no. 2 (March 2019): 159–80. http://dx.doi.org/10.1134/s0869593819020059.

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14

Brown, G. Malcolm. "Introduction." Geological Magazine 122, no. 5 (September 1985): 415–17. http://dx.doi.org/10.1017/s0016756800035330.

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The Tertiary volcanic centre that dominates the constitution of Rhum, one of the Scottish Inner Hebridean group of islands, is immediately provocative to the visiting geologist. The higher mountains are entirely ultrabasic in composition and their near-horizontal, terraced layers remain nearly constant in composition to about 1 km above sea level. Any initial assumption of geological simplicity is quickly dispelled by those and more detailed features. Horizontal layers of ultrabasic rocks with coarsely crystalline texture do not fit happily on a Tertiary landscape, towering high above the adjacent Hebridean lava flows of similar age. And what of the rocks themselves? Thin layers entirely of calcic plagioclase feldspar compete for attention with thick olivine-rich layers, while any day of traversing the Hallival or Askival mountain slopes will reveal a wealth of superbly exposed question marks in the form of spinel–sulphide layers, slump structures, finger structures, ‘harrisitic olivine’ formations, undulatory ‘trough-like’ structures, ultrabasic veins and currently lesser features. Search as one may (and little is hidden from view), there is no marginal gabbroic envelope between the ultrabasics and the country rocks that would lead to a Skaergaard analogy, and no overlying gabbroic layered rocks that would elicit guidelines from the Bushveld or Stillwater intrusions. This is Rhum, and much of what is on that small island is unique and, indeed, still defies full explanation. It is the achievement of this issue, through its several contributors whose voices succeed mine, that the uniqueness of Rhum is welcomed, many of the problems challenged, and many of the secrets unravelled.

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Popov, K. V., A. M. Gorodnitskiy, and N. A. Shishkina. "MAGNETIC CHARACTERISTICS OF METAMORPHIZED ULTRABASITES OF THE OCEANIC LITHOSPHERE." Journal of Oceanological Research 47, no. 4 (December 2, 2019): 106–27. http://dx.doi.org/10.29006/1564-2291.jor-2019.47(4).7.

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As part of the study of the nature of magnetic anomalies associated with the deep layers of the oceanic crust, a comparative analysis was made of the petromagnetic characteristics of serpentinized mantle ultrabasic samples taken from oceanographic expeditions of the Institute of Oceanology and the Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences in various morphotectonic regions of the World Ocean. The purpose of the work is to obtain information on the composition, concentration, crystallization temperature and structural features of ferromagnetic minerals, which are formed in different conditions of the post-magmatic metamorphism of ultrabasites. Sample collections are divided into three groups. 1. Oceanic peridotites from the rift zones of the mid-ocean ridges and transform faults. 2. Peridotites of the submarine ridge Gorringe, located within the Azoro-Gibraltar zone of faults. 3. Dunites of the Pekulney complex (Chukotka) formed in the island arc system. It has been established that in all selected regions, samples of serpentinized hyperbasites have high values of natural residual magnetization, magnetic susceptibility and saturation magnetization. The highest values of magnetic parameters are the dunites of the Pekulney complex. Estimation of the dependence of the concentration of ferrimagnetic materials C% of the degree of serpentinization of the SS%. showed that it is practically of little significance. The main factors contributing to the increase in the concentration of magnetite are the increased iron content of olivine in ultrabasites and the temperature of metamorphism. The question of the period of formation of magnetites and the stability of their primary residual magnetization requires further study.

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Farquharson, Colin G., and Roy Thompson. "The Blairgowrie magnetic anomaly and its interpretation using simplex optimisation." Transactions of the Royal Society of Edinburgh: Earth Sciences 83, no. 3 (1992): 509–18. http://dx.doi.org/10.1017/s026359330000585x.

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AbstractThe large magnetic anomaly which runs along the Highland Boundary Fault of Scotland immediately to the NW of Blairgowrie has been studied by both a ground-based magnetic survey and a palaeomagnetic investigation. A newly developed optimisation program, making use of a simplex algorithm, was used to model the long wavelength component of this effectively two-dimensional anomaly. The consequent model consists of a vertical, rectangular body, 3 km wide and 13 km deep, whose top surface is 2 km below ground level, with a magnetisation directed vertically downwards. The composition of this body is most likely to be that of an ultra-basic, metamorphic complex which has been brought up to its present position between two of the many near-vertical faults in the area. The medium wavelength structure of the anomaly was modelled using the common technique of trial and error, and can be interpreted in terms of a pair of Devonian andesitic lavas and a small extension of the main ultrabasic block. Subsequent palaeomagnetic remanence measurements confirmed that the magnetisation of the two lavas recorded a Devonian polarity reversal. The magnetisation of the ultrabasics is directed vertically downwards, exactly as deduced from the earlier modelling work.

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Aiba, Shin-Ichiro, and Kanehiro Kitayama. "Effects of the 1997–98 El Niño drought on rain forests of Mount Kinabalu, Borneo." Journal of Tropical Ecology 18, no. 2 (March 2002): 215–30. http://dx.doi.org/10.1017/s0266467402002146.

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We examined the effects of the 1997–98 El Niño drought on nine rain forests of Mount Kinabalu, Borneo, at four altitudes (700, 1700, 2700 and 3100 m) on contrasting geological substrata (ultrabasic versus non-ultrabasic). Measurements of rainfall and atmospheric aridity indicated that the departure from normal conditions during the drought became greater with increasing altitude. During 1997–99 (drought period) compared to 1995–97 (pre-drought period), median growth rates of stem diameter of trees decreased for both smaller (4.8–10 cm) and larger (≥ 10 cm) diameter classes in the six upland forests (≥ 2700 m on ultrabasic substrata and ≥ 1700 m on non-ultrabasic substrata), but for neither diameter class in the other forests. The majority of species decreased or did not change growth rates during 1997–99, whereas some did increase. Tree mortality increased during 1997–99, at the larger diameter class in the two lowland forests (700 m) on both substrata, and at least at the smaller diameter class in the four upland forests (≥ 1700 m) on non-ultrabasic substrata. In two of these upland forests, mortality was restricted to particular understorey species. Mortality did not significantly increase in the three upland forests (≥ 1700 m) on ultrabasic substrata; this suggests that the adaptation to nutrient-poor soils might have provided the resistance to drought.

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Pulunggono, Heru Bagus, Moh Zulfajrin, and Fuadi Irsan. "Distribution of nickel (Ni) in peatland situated alongside mineral soil derived from ultrabasic rocks." SAINS TANAH - Journal of Soil Science and Agroclimatology 18, no. 1 (June 30, 2021): 15. http://dx.doi.org/10.20961/stjssa.v18i1.45417.

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<p>Detailed studies of Ni distribution in peat that is influenced by Ni-rich soil derived from ultrabasic rocks are still limited. The objective of this study was to reveal the characteristics of Ni in peat from Morowali (Central Sulawesi Province, Indonesia) at several depths and distances from the boundary of the ultrabasic mineral soil. Peat was sampled from depths of 0–30, 30–60, and 60–90 cm at distances of 100, 200, 300, 400, 500, and 600 m from the border of the ultrabasic mineral soil in March 2018. Ni characteristics were examined through their total, exchangeable, water-soluble, and adsorbed distributions. The relationships between Ni and some peat chemical properties such as pH; cation exchange capacity; macronutrient contents of K, Ca, and Mg; and micronutrient contents of Fe, Cu and Zn were also observed. The high Ni content in peat at the study transect is caused by an accumulation of Ni transported from elevated areas of mineral soil. Most Ni in peat is bonded to the soil organic exchange complexes. Accumulation of the mineral soil fraction in the peat surface is indicated at distances of 100–400 meters from the ultrabasic mineral soil. Ni distribution in peat at the study transect is mainly governed by a combination of Fe, pH, organic material, water content, peat depth, and distance from ultrabasic mineral soil.</p>

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Bridges, J. C., H. M. Prichard, and C. A. Meireles. "Podiform chromitite-bearing ultrabasic rocks from the Bragança Massif, northern Portugal: fragments of island arc mantle?" Geological Magazine 132, no. 1 (January 1995): 39–49. http://dx.doi.org/10.1017/s0016756800011419.

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AbstractThe Upper Allochthonous Thrust Complex (UATC) of the Bragança massif in northern Portugal contains a set of ultrabasic rocks interthrust with granulites. The ultrabasic rocks have refractory silicate mineral and whole rock compositions which indicate an origin as depleted mantle. Phase relationships of harzburgite samples suggest that they formed in equilibrium with high-Mg picritic melts created through a high degree of mantle partial melt extraction. Chromite in small podiform deposits has 100 Cr/(Cr + Al) ratios of 62–85, which are consistent with crystallization from such melts. Most of the chromite composition parameters are similar to those of ophiolite deposits except for the high ferric iron contents (2.77–8.95 wt% Fe2O3). Such enrichment is a feature of chromite from island arc magmas. It is suggested that the extensive partial melt extraction and chromite mineralization in the ultrabasic rocks occurred in the upper few kilometres of island arc mantle. The ultrabasic rocks were tectonically emplaced into a granulite and eclogite-bearing arc-continent collision complex during the Early Ordovician and subsequently, in the mid-Devonian emplaced over the Central-Iberian terrane.

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Litvin, Yu A., A. V. Kuzyura, and E. B. Limanov. "The role of garnetization of olivine in olivine-diopside-jadeite system in the ultramafic-mafic evolution of the upper-mantle magmatism (experiment at 6 GPa)." Геохимия 64, no. 10 (November 19, 2019): 1026–46. http://dx.doi.org/10.31857/s0016-752564101026-1046.

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Peritectic mechanisms, controlling fractional ultrabasic-basic evolution of the upper mantle magmatism and genesis of the peridotitepyroxeniteeclogite rock series, are substantiated in theory and experiment. Melting phase relations of a differentiated mantle material are studied with polythhermal section method in the multicomponent olivineclinopyroxene/omphacitecorundumcoesite system with boundary compositions duplicated these of peridotitic and eclogitic minerals. The peritectic reaction of orthopyroxene and melt with formation of clinopyroxene (the opthopyroxene clinopyroxenization reaction) has been determined at a liquidus surface of the ultrabasic olivineorthopyroxeneclinopyroxenegarnet system. As a result of the reaction the temperature-regressive univariant curve olivine + clinopyroxene + garnet + melt is formed. A further evolution of magmatism has experimentally studied at 6 GPa in the ultrabasic-basic olivinediopsidejadeitegarnet system with changeable compositions of the diopsidejadeite solid solutions (controlling the clinopyroxene omphacite mineralogy). Peritectic reaction of olivine and melt with formation of garnet was established on the liquidus surface of the ternary olivinediopsidejadeite system as the mechanism of olivine garnetization and going to the univariant curve omphacitegarnetmelt with formation of bimineral eclogites. Structure of the liquidus surface for the olivinediopsidejadeitegarnet system is inferred, and its role as a physic-chemical bridge between ultrabasic olivinebearing peridotitepyroxenitic and basic silica-saturated eclogitic compositions of the garnetperidotite facies matter. The new experimental physic-chemical results reveal the genetic links between ultrabasic and basic rocks as well as mechanisms of the uninterrupted fractional magmatic evolution and petrogenesis from the olivinebearing peridotitepyroxenitic to silica-saturated eclogite-grospyditicrocks. This provides an explanation for the uninterrupted composition trends for rock-forming components in clinopyroxenes and garnets of the differentiated rocks of the garnetperidotite facieis.

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Petrounias, P., A. Rogkala, M. Kalpogiannaki, B. Tsikouras, and K. Hatzipanagiotou. "COMPARATIVE STUDY OF PHYSICOMECHANICAL PROPERTIES OF ULTRABASIC ROCKS AND ANDESITES FROM CENTRAL MACEDONIA (GREECE)." Bulletin of the Geological Society of Greece 50, no. 4 (July 28, 2017): 1989. http://dx.doi.org/10.12681/bgsg.11945.

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Petrographic, geochemical and physicomechanical features were determined and inter-correlated in two representative ultrabasic samples from the Veria-Naousa ophiolite and two Pliocenic andesite samples, occurring at the east of the above complex. Results show that mineralogical and textural features are major factors affecting the physicomechanical properties in both lithotypes. The ultrabasic rocks display higher resistance to attrition and abrasion and lower water absorption values relative to the intermediate volcanic rocks, hence the first are predicted to show better in-service engineering performance. However, the degree of serpentinisation is detrimental, as a highly serpentinised ultrabasic sample yielded poor results, analogous to the andesites, in certain laboratory tests. Ophiolite complexes in Greece are abundant and they are distributed along several mainland areas. Hence setting evaluation criteria for their quality is important as they can potentially replace limestones, which are less resistant and durable, in several environmental and industrial applications

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Claydon, R. V., and B. R. Bell. "The structure and petrology of ultrabasic rocks in the southern part of the Cuillin Igneous Complex, Isle of Skye." Transactions of the Royal Society of Edinburgh: Earth Sciences 83, no. 4 (1992): 635–53. http://dx.doi.org/10.1017/s0263593300003345.

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AbstractThe ultrabasic rocks of the southern portion of the Early Tertiary Cuillin Igneous Complex, Isle of Skye, are recognised as forming a Peridotite Series s.l. and have been separated into six distinct structural–lithological units. These units range from almost pure dunite (Unit 1, at the lowest structural level), through to feldspathic peridotites and allivalites (Units 5 and 6, at the highest structural levels). Detailed field and mineralogical studies indicate that both cumulus and postcumulus processes involving ultrabasic (picritic) magmas may be identified, and that the latter processes have significantly modified many of the primary features of these rocks.Layering, both modal and phase, is present within all six units, although it is more prominent within the higher units, especially Units 5 and 6. Differing orientations of fabrics defined by cumulus spinel and intercumulus plagioclase layers within Unit 3 indicate the important role of compaction and intercumulus melt migration. Unit 4 is extremely heterogeneous, involving material ranging in composition from peridotite to allivalite, and provides clear evidence for postcumulus melt movement, magma-mixing, disruption and brecciation. Units 5 and 6 developed with a more porous cumulus framework, giving rise to dendritic growths involving cumulus olivine and poikilitic plagioclase.It is concluded that postcumulus melt movement, injection and magma-mixing, involving ultrabasic magmas, were significant processes in the formation of the ultrabasic rocks of the Cuillin Igneous Complex.

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Biryukova, A. A., T. D. Dzhienalyev, and A. V. Boronina. "Ceramic Proppants Based on Ultrabasic Rocks of Kazakhstan Chromite Ore Deposits." Materials Science Forum 946 (February 2019): 169–73. http://dx.doi.org/10.4028/www.scientific.net/msf.946.169.

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The purpose of the work is the obtaining of magnesium silicate ceramic proppants, based on ultrabasic overburden rocks of Kempirsai deposits of chromite ores (Kazakhstan). The chemical and mineralogical composition of ultrabasic overburden rock was studied by chemical, microscopic and X-ray diffraction analyzes. It is established that the main mineral of ultrabasic overburden rocks is serpentine, present in the form of fibrous chrysotile and lamellar antigorite. In the impurities are iron oxides and hydroxides, chrome spinel, carbonates, quartz. Assessment of the use of overburden rocks as a raw material for the production of ceramic proppants was carried out. The sintering interval of overburden rocks was determined at 1280-1300 °C. The sintering firing optimum temperature of ceramics, based on this type of raw material is 1300 °C. It is established that to harden the structure of magnesium silicate ceramic it is necessary to activate the raw material thermally at a temperature of 1000 °C. The influence of binder type on the properties of magnesium silicate proppants, based on the Kempirsai serpentinites was studied. Magnesium silicate proppants, based on ultrabasic overburden rocks, were obtained with the following properties: apparent density – 1.6 g/cm3, strength resistance (52 MPa) – 14%, sphericity and roundness – 0.8; chemical resistance (hydrochloric acid) – 98%, static strength of the fraction 16/20 - 72–118 N/granule. The field of application is oil and gas production, metallurgy and ceramic industries.

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Laznicka, Peter. "Metallogeny of basic and ultrabasic rocks." Geoexploration 25, no. 3 (October 1988): 263–64. http://dx.doi.org/10.1016/0016-7142(88)90021-x.

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Diamantis, K., Th Karamousalis, Vas Antoniou, and G. Migiros. "UNIAXIAL COMPRESSIVE STRENGTH, DRY UNIT WEIGHT AND FRACTURE PATTERNS OF ULTRABASIC ROCKS IN OTHRYS MOUNTAIN (CENTRAL GREECE): CORRELATIONS AND EVALUATION." Bulletin of the Geological Society of Greece 40, no. 1 (June 8, 2018): 264. http://dx.doi.org/10.12681/bgsg.16550.

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Ultrabasic rocks, taken from the Othrys mt. (Central Greece), are studied in this paper. The structural geology and tectonics of the study area are described. Uniaxial Compressive Strength (UCS) and dry unit weight (γ) values are calculated and fracture angles are measured. The results are statistically assessed and empirical relationships (exponential equations) between UCS and γ are presented for the ultrabasic roch, divided in Peridotites, Serpentinised Peridotites and Serpentinites. Due to the low correlation coefficient of the Serpentinised Peridotites, it was decided that the Serpentinised Peridotites and Serpentinites should be examined together. The correlation coefficient of the combined category is much better than the separate ones. Furthermore, this paper demonstrates that the majority of the ultrabasic rocks tested were breaking at one angle (φ°), which mainly fluctuated between 75° and 90°. The fracture angles correlate with previously recognised geological (mainly tectonic) structures. The observed deviations are due to pétrographie variety, structural complexity, preferred orientation of olivine and orthopyroxene and internal imprinted tectonic deformation.

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Volker, J. A., and B. G. J. Upton. "The structure and petrogenesis of the Trallval and Ruinsival areas of the Rhum ultrabasic complex." Transactions of the Royal Society of Edinburgh: Earth Sciences 81, no. 1 (1990): 69–88. http://dx.doi.org/10.1017/s0263593300005137.

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ABSTRACTDetailed mapping of the Trallval-Ruinsival area of the ultrabasic complex of Rhum has revealed the relationship between the intrusive peridotites, which form a major part of the complex, and the layered ultrabasic rocks. The layered rocks on Trallval are correlated with Units 8 to 15 of the Eastern Layered Series as seen on Hallival and Askival, and part of an additional unit, Unit 16, has also been identified. The layered rocks of Ruinsival and the western part of Trallval form part of the Central Series and have been subdivided into six cyclic units. They are associated with four sets of intrusive breccia zones which converge towards a central region. Four cylindrical plugs of intrusive peridotite occur within the area of outcrop of the Central Series. Criteria are listed for the distinction of intrusive peridotite from conformable peridotites formed in situ. Distinctive textures and structures are described; these include vertical feldspathic streamers, which are interpreted as direct evidence for the upward expulsion of interstitial fluid, and loading structures at the contact between a peridotite layer and underlying allivalite are ascribed to the intrusion of a peridotite sill. A comparison of the Eastern Layered Series and the Central Series suggests that three stages were involved in the formation of the ultrabasic rocks: (i) the accretion of rhythmically layered unconsolidated olivine cumulates; (ii) the upward expulsion of intercumulus liquid; and (iii) the formation of either allivalite (as in the Eastern Layered Series) or ultrabasic breccia zones (as in the Central Series) from the expelled intercumulus liquid, depending on whether the tectonic environment was quiescent or extensional.

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Emeleus, C. H., and V. R. Troll. "The Rum Igneous Centre, Scotland." Mineralogical Magazine 78, no. 4 (August 2014): 805–39. http://dx.doi.org/10.1180/minmag.2014.078.4.04.

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AbstractThe publication of the British Geological Survey memoir on Rum and the Small Isles in 1997 was followed by a period of intense petrological and mineralogical research, leading to some 40 papers, books and other publications. The research progress since then is reviewed here and integrated with the information previously available to provide an overview of the current status of understanding of the centre. New data on the acidic and mixed acid/basic magmas of the early Rum caldera demonstrate that frequent mafic replenishments were the main driver for magmatic activity at Rum right from its initial stages. The caldera is bound by the Main Ring Fault, a structure which probably also exercised an influence on the emplacement of the subsequent basic and ultrabasic intrusions. The later emplacement of gabbros and ultrabasic rocks caused only limited thermal metamorphism of the surrounding Torridonian sandstones, contrasting markedly with the crustal isotope signatures of the early intracaldera ignimbrite magmas and the intense alteration of uplifted masses of Lewisian gneiss within the ring fault. Rare picritic dykes provide an indication of the possible parent magma for the mafic and ultrabasic rocks, but these, as with most other magmatic rocks on Rum, have undergone varying degrees of crustal contamination, involving both Lewisian granulite and amphibolite-type crust but, notably, no Moine metasedimentary compositions as is the case at the nearby Ardnamurchan centre. Detailed textural studies on the gabbroic and ultrabasic rocks allow a distinction between intrusive peridotites and peridotite that forms part of the classic layered cumulate units of Rum and, furthermore, this work and that on the chromite seams and veins in these rocks shows that movement of trapped magma and magma derived from later intrusions, may produce textures regarded previously as of primary cumulate origin. Sulfides in the chromitite seams and ultrabasic rocks, in turn, show possible influences from assimilated Mesozoic sediments. Igneous activity on Rum was short-lived, possibly only between 0.5 and 1 m.y. in duration and commenced at ∼60.5 Ma. The Rum Central Complex was extinct by the time the main activity at the nearby Skye Central Complex commenced (∼59 Ma). From recent apatite fission-track studies it seems probable that Rum, in common with other Palaeogene centres, underwent a brief, but significantly later heating event (∼45 Ma).

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KAINO, Toshikuni. "Control of Time for Ultrabast Signal Detection." Kobunshi 51, no. 12 (2002): 960. http://dx.doi.org/10.1295/kobunshi.51.960.

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Sawada, Yoshimi, Shin-ichiro Aiba, Masaaki Takyu, Rimi Repin, Jamili Nais, and Kanehiro Kitayama. "Community dynamics over 14 years along gradients of geological substrate and topography in tropical montane forests on Mount Kinabalu, Borneo." Journal of Tropical Ecology 31, no. 2 (February 2, 2015): 117–28. http://dx.doi.org/10.1017/s0266467414000777.

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Abstract:To understand the variation in community dynamics of tropical montane forests along gradients of soil fertility, death, recruitment and growth of trees (≥5 cm diameter) were monitored over 14 y (1997–2011) in nine plots placed in a matrix of three geological substrate types (Quaternary sediments, Tertiary sedimentary rocks and ultrabasic rocks) and three topographical units (ridge, middle and lower slopes) on Mount Kinabalu, Borneo. The plot area was 0.05 ha for ridge, 0.1 ha for middle slope and 0.2 ha (on ultrabasic rocks) and 1 ha (on the other substrates) for lower slope. Recruitment rates did not show a consistent pattern across geological substrates or topographies. Mortality rates were relatively high in almost all plots during the 1997–1999 period, including the El Niño drought, and in three plots on ultrabasic rocks during 2001–2005. Binomial logistic regression analyses showed that mortality during 1997–1999 increased with soil fertility (soluble phosphorus). Background mortality, excluding these periods, did not differ across geological substrates or topographies. The average growth rate during 1997–2011 was higher on more fertile soils and positively correlated with mortality during 1997–1999. We suggest that a high mortality rate during the drought period was related to high species diversity on more fertile soils, whereas a lower growth rate was related to stunted structures on poorer soils.

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Williams, David A., Laszlo Keszthelyi, and John Stansberry. "New Io data spur discussion on ultrabasic lavas." Eos, Transactions American Geophysical Union 81, no. 22 (2000): 249. http://dx.doi.org/10.1029/00eo00174.

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Rigopoulos, Ioannis, Basilios Tsikouras, Panagiotis Pomonis, and Konstantin Hatzipanagiotou. "Microcracks in ultrabasic rocks under uniaxial compressive stress." Engineering Geology 117, no. 1-2 (January 2011): 104–13. http://dx.doi.org/10.1016/j.enggeo.2010.10.010.

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32

Afonin, Yu A., and I. G. Maryasev. "Cryptocrystalline magnesite in weathering crust of ultrabasic rocks." Refractories and Industrial Ceramics 47, no. 5 (September 2006): 269–74. http://dx.doi.org/10.1007/s11148-006-0105-y.

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Join, Jean-Lambert, Bernard Robineau, Jean-Paul Ambrosi, Claire Costis, and Fabrice Colin. "Système hydrogéologique d'un massif minier ultrabasique de Nouvelle-Calédonie." Comptes Rendus Geoscience 337, no. 16 (December 2005): 1500–1508. http://dx.doi.org/10.1016/j.crte.2005.08.011.

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34

Madugalla, T. B. N. S., H. M. T. G. A. Pitawala, R. Naumann, and R. B. Trumbull. "Hydrothermal mica deposits in altered meta-ultrabasites from north-central Sri Lanka." Journal of Geochemical Exploration 153 (June 2015): 66–78. http://dx.doi.org/10.1016/j.gexplo.2015.03.002.

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35

Brazelton, William J., Christopher N. Thornton, Alex Hyer, Katrina I. Twing, August A. Longino, Susan Q. Lang, Marvin D. Lilley, Gretchen L. Früh-Green, and Matthew O. Schrenk. "Metagenomic identification of active methanogens and methanotrophs in serpentinite springs of the Voltri Massif, Italy." PeerJ 5 (January 26, 2017): e2945. http://dx.doi.org/10.7717/peerj.2945.

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The production of hydrogen and methane by geochemical reactions associated with the serpentinization of ultramafic rocks can potentially support subsurface microbial ecosystems independent of the photosynthetic biosphere. Methanogenic and methanotrophic microorganisms are abundant in marine hydrothermal systems heavily influenced by serpentinization, but evidence for methane-cycling archaea and bacteria in continental serpentinite springs has been limited. This report provides metagenomic and experimental evidence for active methanogenesis and methanotrophy by microbial communities in serpentinite springs of the Voltri Massif, Italy. Methanogens belonging to family Methanobacteriaceae and methanotrophic bacteria belonging to family Methylococcaceae were heavily enriched in three ultrabasic springs (pH 12). Metagenomic data also suggest the potential for hydrogen oxidation, hydrogen production, carbon fixation, fermentation, and organic acid metabolism in the ultrabasic springs. The predicted metabolic capabilities are consistent with an active subsurface ecosystem supported by energy and carbon liberated by geochemical reactions within the serpentinite rocks of the Voltri Massif.

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36

Volker, J. A., and B. G. J. Upton. "Reply to comments by J. H. Bédard and R. S. J. Sparks." Transactions of the Royal Society of Edinburgh: Earth Sciences 82, no. 4 (1991): 391. http://dx.doi.org/10.1017/s0263593300004235.

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Bédard and Sparks' (BS) comments are very much appreciated as they giveus the opportunity to emphasise certain aspects of our observations which, in turn, mayclarify the discussion on the petrogenesis of the Rhum ultrabasic rocks. BS raised two questions which we answer below.

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Szczepańska, Katarzyna, Maria Kossowska, and Karina Wilk. "Caloplaca subpallida (Teloschistaceae), a lichen species new to Poland: distribution, ecology and taxonomic affinities." Acta Societatis Botanicorum Poloniae 81, no. 4 (2013): 85–89. http://dx.doi.org/10.5586/asbp.2013.007.

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<em>Caloplaca subpallida</em> is reported from basic and altered ultrabasic rocks (i.e. basalt, greenstone, and serpentinite) at nine sites in SW Poland. A detailed description of the species and a discussion on its taxonomic affinities are provided.

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Боярских (Boyarskikh), Ирина (Irina) Георгиевна (Georgievna), Александр (Аleksandr) Иванович (Ivanovich) Сысо (Syso), and Татьяна (Tat'yana) Ивановна (Ivanovna) Сиромля (Siromlya). "MINERAL COMPOSITION OF LONICERA CAERULEA PHYTOMASS IN CONTRASTING GEOCHEMICAL ENVI-RONMENTS." chemistry of plant raw material, no. 3 (April 2, 2018): 129–38. http://dx.doi.org/10.14258/jcprm.2018033740.

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To study mineral composition of honeyberry (Lonicera caerulea L.) phytomass in contrasting geochemical environments, the accumulation of macro- and trace elements, as related to their soil content in undisturbed Mountainous Altai ecosystems, was determined in organs of the Altai subspecies of honeyberry, growing in the geochemically anomalous environment on ultrabasic rocks and in the geochemically normal environment. Total chemical element content in soil and plants was determined by atomic emission spectrometry, while labile forms of К, Na, Ca, Mg, Fe, Mn, Zn, Cu, Ni, Li, Sr were measured by atomic adsorption spectrometry. Organ distribution and variation limits were determined for 30 macro- and trace elements. Leaves were shown to accumulate Sr, Ni, Mo, B, Ga, La and Zr more intensively in comparison with stems, while the latter accumulated more intensively Al, Cu, Mn and Zn. Plants grown on ultrabasic rocks had decreased Ca, K, Fe and Sr contents and increased Mg and Ni contents as compared with plants growing on acidic, carbonated and basic rocks. Decreased rate of K, Ca and Sr uptake by honeysuckle plants was most likely due to the mineral exchange distortion because of soil Ca/Mg ratio, which was unfavourable for plants. Leaves of plants growing on the ultrabasic rocks were shown to accumulate Ni in high concentrations. Increased Fe accumulation was found in leaves of plants growing on basic rocks, while stems had increased Fe concentrations in all study sites. The obtained results should be carefully considered for the purposed of phytomass collection and preparation for medicinal use.

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Fejza, Islam, Sabri Avdullahi, Avni Meshi, Murat Meha, and Ahmet Tmava. "Ultrabasic Massif of Goleshi (Kosova): Microstructural and Kinematic Analysis." Online Journal of Earth Sciences 4, no. 1 (January 1, 2010): 6–12. http://dx.doi.org/10.3923/ojesci.2010.6.12.

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40

Agee, Carl B., and David Walker. "Static compression and olivine flotation in ultrabasic silicate liquid." Journal of Geophysical Research 93, B4 (1988): 3437. http://dx.doi.org/10.1029/jb093ib04p03437.

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41

Kato, Takumi, Eiji Ohtani, Yoshiki Ito, and Kosuke Onuma. "Element partitioning between silicate perovskites and calcic ultrabasic melt." Physics of the Earth and Planetary Interiors 96, no. 2-3 (August 1996): 201–7. http://dx.doi.org/10.1016/0031-9201(96)03151-2.

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42

Navarrete, Ian A., Victor B. Asio, Reinhold Jahn, and Kiyoshi Tsutsuki. "Characteristics and genesis of two strongly weathered soils in Samar, Philippines." Soil Research 45, no. 3 (2007): 153. http://dx.doi.org/10.1071/sr06103.

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Very limited data have been published on the nature of strongly weathered soils in geologically young humid tropical islands. The study evaluated the characteristics and formation of 2 strongly weathered soils in the island of Samar, Philippines, one developed from slate (Bagacay soil) and the other from ultrabasic rock (Salcedo soil). Results revealed that the soils have generally similar morphological characteristics, particularly in terms of colour (2.5 YR-10 R), solum thickness (>5.0 m), and structure (granular to subangular blocky), although the Salcedo soil has much higher clay content than the Bagacay soil. Both soils have similar chemical properties (e.g. acidic, low exchangeable bases) except that the Salcedo soil has lower CEC values but higher exchangeable Na content, resulting in a higher base saturation. They also have high dithionite-extractable Fe contents and very low oxalate/dithionite ratios and are dominated by halloysite, kaolinite, gibbsite, goethite, hematite, and quartz in the clay fraction. Apparently as a result of its more weatherable ultrabasic parent rock and more stable geomorphic surface, the Salcedo soil shows more advanced weathering and soil development than the Bagacay soil. Salcedo soil is classified as Haplic Ferralsol (Dystric, Clayic, Rhodic) in the World Reference Base or very fine, sesquic, isohyperthermic, Rhodic Hapludox in the Soil Taxonomy. Bagacay soil is a Haplic Acrisol (Alumic, Hyperdystric, Clayic, Rhodic) or fine, kaolinitic, isohyperthermic, Typic Paleudult. The Salcedo soil has very high Ni and Cr contents inherited from its ultrabasic parent material. The study reveals that on the geologically young humid tropical island of Samar, the characteristics and genesis of strongly weathered soils are greatly affected by the geochemical characteristic of the parent rock material.

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43

Spray, John G. "Thrust-related metamorphism beneath the Shetland Islands oceanic fragment, northeast Scotland." Canadian Journal of Earth Sciences 25, no. 11 (November 1, 1988): 1760–76. http://dx.doi.org/10.1139/e88-167.

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A ≤400 m thick metamorphic sequence showing thermal inversion is present beneath a dismembered ultrabasic–basic complex in the Shetland Islands of northeast Scotland. The metamorphic grade changes from upper amphibolite facies in metabasites at the top of the sequence to low greenschist facies in metasediments at the base. Garnet–clinopyroxene thermometry yields temperatures of ~ 750 °C (at 300 MPa) for the highest grade assemblage. There is no evidence for high pressures of metamorphism, and maximum overburden may never have exceeded the original thickness of the overlying ultrabasic–basic complex, which is estimated to have been ~ 10 km.The internal structure and field relations of the ultrabasic–basic complex reveal that it is a displaced fragment of oceanic crust and upper mantle of Ordovician age. The chemistry of its basic lithologies suggests low-K tholeiite, suprasubduction zone, pre-arc affinities. In contrast, the underlying meteamorphic sequence possesses a mid-ocean ridge basalt (MORB) signature.Four K–Ar age determinations from amphibole mineral separates of the metamorphic sequence range from 479 ± 6 to 465 ± 6 Ma. The highest age is interpreted as the date of the onset of metamorphic sole formation and the initial tectonic displacement of the oceanic fragment.It is concluded that the metamorphic sequence was generated during intraoceanic thrusting during the destruction of a young, marginal oceanic basin located between a continental margin and the ocean lithosphère of Iapetus. Certain MORB lithologies were metamorphosed and transferred to the marginal basin hanging wall during the subduction of Iapetus. Apparent thermal inversion was caused during overthrusting by the gradual underplating of the hanging wall in close proximity to a suprasubduction zone spreading centre.

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44

Steenfelt, Agnete, Julie A. Hollis, and Karsten Secher. "The Tikiusaaq carbonatite: a new Mesozoic intrusive complex in southern West Greenland." Geological Survey of Denmark and Greenland (GEUS) Bulletin 10 (November 29, 2006): 41–44. http://dx.doi.org/10.34194/geusb.v10.4905.

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Ultrabasic alkaline magmatic rocks are products of melts generated deep within or at the base of the lithospheric mantle. The magmas may reach the surface to form lavas and pyroclastic deposits; alternatively they crystallise at depth to form dykes or central complexes. The rocks are chemically distinct and may contain high concentrations of economically interesting minerals and chemical elements, such as diamonds, niobium, tantalum, rare earth elements, phosphorus, iron, uranium, thorium, and zirconium. Ultrabasic alkaline rocks are known from several provinces in Greenland, but extrusive facies have only been preserved at a few places; e.g. at Qassiarsuk in South Greenland where pyroclastic rocks occur, and in the Maniitsoq region, where a small volcanic breccia (‘Fossilik’) contains fragments of Palaeozoic limestone. Ultramafic lamprophyre and kimberlite are mainly emplaced as dykes, whereas carbonatite forms large intrusive bodies as well as dykes. The ultrabasic alkaline magmas that have been emplaced at certain times during the geological evolution of Greenland can be related to major episodes of continental break-up (Larsen & Rex 1992). The oldest are Archaean and the youngest dated so far are Palaeogene. Figure 1 shows the distribution of known ultrabasic alkaline rocks in West Greenland. The large and well-exposed bodies of alkaline rocks and carbonatites in the Gardar Province were discovered already in the early 1800s (Ussing 1912), while less conspicuous bodies were discovered much later during geological mapping and mineral exploration. Many alkaline rock bodies, particularly dykes, are difficult to identify in the field because they weather more extensively than the country rock gneisses and form vegetated depressions in the landscape. However, their distinct chemistry and mineralogy render alkaline rocks identifiable in geochemical and geophysical survey data. Thus, the Sarfartôq carbonatite complex was discovered during regional airborne gamma-spectrometric surveying owing to its elevated uranium and thorium contents (Secher 1986). The use of kimberlite indicator minerals has led to the discovery of alkaline rocks such as kimberlites and ultramafic lamprophyres that carry fragments of deep lithospheric mantle. Such rocks may also contain diamonds. Kimberlite indicator minerals are high-pressure varieties of minerals, such as garnet, clinopyroxene, chromite and ilmenite that were formed in the lithospheric mantle. Exploration companies have processed thousands of till samples from southern West Greenland for kimberlite indicator minerals and found many new dykes.

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45

Gritsenko, Yu D., and A. A. Serova. "Minerals-concentrators of rare-earth elements in basites-ultrabasites intrusives of Norilsk district." Proceedings of higher educational establishments. Geology and Exploration, no. 3 (June 28, 2017): 56–65. http://dx.doi.org/10.32454/0016-7762-2017-3-56-65.

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The conditions of being, the history of formation and transformation of minerals-concentrators of rare-earth elements (REE) - apatite minerals group and epidote minerals group, have been studied and described. Allanite has been determined to be mostly developed in the halos of the fluid action a solid contact of sulfide ores containing rich pneu matolytic mineralization of the platinum-group elements (PGM) and gold. Apatite and allanite are found among sulfides and in rims of the fluid action over the drops of sulphides in the horizon of the disseminated ores. The composition of Apatite-I has evolved from a OH-containing chlorapatite to chlorapatite containing up to 2,3 wt. % of lanthanides; Apatite-II - from OH-Cl-bearing fluorapatite to fluorapatite. The lanthanides reieased during replacement of chlorapatite-I by fluorapatite-II, probably entering the composition of the produced pneumatoiytic alianite-(Ce). In the areas of mineral ores with imposed metamorphism, the pneumatoiytic apatite partially or totally is substituted by hydroxyapatite-III, allanite - by water-containing allanite with the content of the epidote and clinozoisite minals - 30-35 mol. %. The spectra of REE distribution in apatite have been determined to reflect more accurately their ratios in rocks, the spectra of REE distribution for allanite are characterized by a steeper slope from lighter to heavier lanthanides. The ratio of La, Ce and Nd in chlorapatite corresponds to the distribution of these elements as in the host picrite horizon, as well in the rocks of the intrusives as a whole. Allanite, in return, is more enriched in cerium and lanthanum and depleted in neodymium.

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Kravchenko, G. L. "Metamorphic ultrabasites, basites and magnetite quartzites of Orlovska magnetic anomaly (West Azov area)." Geochemistry and ore formation 34 (2014): 34–49. http://dx.doi.org/10.15407/gof.2014.34.034.

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47

Shmelev, V. R. "Mantle ultrabasites of ophiolite complexes in the Polar Urals: Petrogenesis and geodynamic environments." Petrology 19, no. 6 (November 2011): 618–40. http://dx.doi.org/10.1134/s0869591111060038.

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48

Lagabrielle, Yves, Serge Fudral, and Jean-Robert Kienast. "La couverture océanique des ultrabasites de Lanzo (Alpes occidentales) : arguments lithostratigraphiques et pétrologiques." Geodinamica Acta 4, no. 1 (January 1990): 43–55. http://dx.doi.org/10.1080/09853111.1990.11105199.

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Yatskanich, Elena. "Serpentinization of ultrabasites in pre-Jurassic series: an example of Uvatsky Petroleum District." Oil and gas geology = Geologiya nefti i gaza, no. 4 (August 25, 2021): 67–74. http://dx.doi.org/10.31087/0016-7894-2021-4-67-74.

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50

Cruciani, Gabriele, Marcello Franceschelli, Hans-Joachim Massonne, Giovanni Musumeci, and Massimo Scodina. "Garnet-Rich Veins in an Ultrabasic Amphibolite from NE Sardinia, Italy: An Example of Vein Mineralogical Re-Equilibration during the Exhumation of a Granulite Terrane." Geosciences 10, no. 9 (August 31, 2020): 344. http://dx.doi.org/10.3390/geosciences10090344.

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A complex system of mono- and polymineralic centimeter-thick veins occurs within the ultrabasic amphibolites of Montigiu Nieddu hill in northeastern Sardinia, and they are filled with garnet, amphibole, chlorite, and epidote. Some garnet-rich veins are margined by an amphibole layer at the interface with the host rock and/or show replacement of epidote concentrated in the vein core. Together with homogeneous matrix garnet (Grt1), millimetric, euhedral, and strongly zoned garnet porphyroblasts occur within these veins. The estimated pressure–temperature conditions (P = 1.0–1.7 GPa, T = 650–750 °C) for the formation of Grt1 match the metamorphic peak and early exhumation derived previously for the host rocks and confirm that the garnet veins also formed under high-pressure (HP) conditions. The igneous protolith of the host rocks experienced HP metamorphism in a subduction zone and underwent exhumation in an exhumation channel. The vein system in the ultrabasic amphibolites formed by cyclic hydrofracturing as rapid and transient events such as crack-seal veining. The growth of multiple vein-filling mineral assemblages indicates the formation of separate vein-producing cycles.

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Journal articles on the topic 'Ultrabasite'

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