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Journal articles on the topic 'Calc-silicate'

Author: Grafiati

Published: 4 June 2021

Last updated: 3 February 2022

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1

Owen, J. V., J. Dostal, and B. N. Church. "Mineralogic reaction zones at a calc-silicate/metapelite interface: an example of trace element mobility in a metamorphic environment." Mineralogical Magazine 58, no. 391 (June 1994): 205–14. http://dx.doi.org/10.1180/minmag.1994.058.391.03.

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AbstractMetasomatic interaction on a cm scale between calc-silicate pods and the enclosing sillimanite + biotite + tourmaline gneiss at Partridge Breast Lake, northern Manitoba, Canada, led to the development of an inner (by calc-silicate rock), hornblende-rich reaction zone and an outer, biotite-rich zone. The boundary between the reaction zones is interpreted as the original calc-silicate/metapelite interface. Compared with its metapelitic protolith, the biotite zone shows a two- to twenty-fold depletion in the concentrations of incompatible trace elements (notably the light rare earths, U, Th, Nb, Ta, Zr and Hf). In contrast, the relative concentrations of trace elements remained nearly constant during the mineralogical transformation of the calc-silicate rock to the hornblende zone. The depletion of trace elements in the biotite zone is attributed to the dissolution of accessory phases (e.g. monazite). Although stable at the metamorphic conditions (∼600–650°C at ∼ 4.5 kbar) prevalent during metasomatism, Mg-rich tourmaline is absent in the biotite zone, suggesting that either the pH or composition (e.g. the (Al + Si)/(Ca + Mg + Fe) ratio) of the aqueous fluid phase was inappropriate for the preservation of this mineral.

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2

Harris, Chris, and Lucrecia Maboane. "The Garies wollastonite deposit, Namaqualand, South Africa: High-Temperature metamorphism of a low-δ18O skarn?" Canadian Mineralogist 59, no. 3 (May 1, 2021): 495–510. http://dx.doi.org/10.3749/canmin.2000071.

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ABSTRACT The Garies wollastonite deposit is located in the Bushmanland terrane of the Namaqualand Metamorphic Province and is part of a discontinuous calc-silicate unit bounded by granulite facies gneiss that experienced peak metamorphic temperatures above 800 °C. In bulk, the deposit is dominated by wollastonite, but varied proportions of garnet, diopside, quartz, calcite, and vesuvianite are also present. Mineral chemistry variations across the deposit are minor, and the absence of inclusions indicates textural and chemical equilibrium. The wollastonite-bearing rocks have unusually low mineral δ18O values: –0.6 to +2.2‰ for garnet, –0.2 to +2. 6‰ for clinopyroxene, and –0.2 to +0.4‰ for wollastonite. Calcite δ18O values range from 6.8 to 11. 8‰ and δ13C values from –6.4 to –3.2‰. Calcite δ18O values are unusually low for calc-silicate rocks, but Δcalcite-garnet values from 3 to 12‰ indicate O-isotope disequilibrium between calcite and the silicate minerals. Garnet-biotite metapelitic and diopside gneisses have unexpectedly low δ18O values (<7‰). The approach to O-isotope equilibrium displayed by coexisting silicate minerals, and low mineral δ18O values in calc-silicate and metapelite and metapsammite gneisses, is consistent with low δ18O values being acquired before peak metamorphism. Low δ18O values in the minerals of the calc-silicate rocks require interaction with external fluid at high water/rock ratio. We suggest that the deposit represents a metamorphosed skarn that developed at the contact between the original carbonate rocks and intruding felsic magmas.

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3

Alderton, D. H. M. "Calc-Silicate Minerals from the Dartmoor Granite." Mineralogical Magazine 52, no. 367 (September 1988): 527–29. http://dx.doi.org/10.1180/minmag.1988.052.367.13.

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4

Sklyarov, Eugene V., Nikolai S. Karmanov, Andrey V. Lavrenchuk, and Anastasia E. Starikova. "Perovskites of the Tazheran Massif (Baikal, Russia)." Minerals 9, no. 5 (May 27, 2019): 323. http://dx.doi.org/10.3390/min9050323.

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The paper provides details of local geology and mineralogy of the Tazheran Massif, which was the sampling site of perovskite used as an external standard in perovskite U-Pb dating by sensitive high-resolution ion microprobe (SHRIMP) and laser ablation inductively-coupled plasma (LA–ICP–MS) mass spectrometry. The Tazheran Massif is a complex of igneous (mafic dikes, syenite, nepheline syenite), metamorphic (marble), and metasomatic (skarn, calc–silicate veins) rocks. Metasomatites are thin and restricted to the complex interior being absent from the margins. Perovskite has been studied at four sites of metasomatic rocks of three different types: forsterite–spinel calc–silicate veins in brucite marble (1); skarn at contacts between nepheline syenite and brucite marble (2), and skarn-related forsterite–spinel (Fo-Spl) calc–silicate veins (3). Pervoskite from Fo-Spl calc–silicate veins (type 1) is almost free from impurities (<1 wt.% in total: 0.06%–0.4% REE2O3, 0.10%–0.22% Nb2O5, ≤0.1% ThO2). The U contents are from 0.1 to 1.9 wt.% UO2 and are relatively uniform in perovskites from the same vein but differ from vein to vein of this type. Perovskite from the contact skarn (type 2) contains 1.5 to 4.5 wt.% REE2O3 but is poor in other impurities. Perovskite grains from skarn-related Fo-Spl calc–silicate rocks (type 3) belong to two generations that differ in REE, Nb, Th, Fe, and Na concentrations. Early-generation perovskites occurs as compositionally homogeneous octahedral or cubic-octahedral crystals with contents of impurities higher than in other varieties (3.6 wt.% REE2O3, 1.6 wt.% Fe2O3, 1.3 wt.% Nb2O5, 0.7 wt.% ThO2, 0.6 wt.% UO2, and 0.6 wt.% Na2O) but the lowest is at the respective site. Late-generation varieties show highly variable impurity concentrations of 1.5 to 22.7 wt.% REE2O3, 0.4 to 8.4 wt.% Nb2O5, and 0.8 to 4.5% ThO2, while the perovskite component may be as low as 65%. In addition to the lueshite and loparite, components, they contain REEFeO3 and Th0.5TiO3 endmembers which have no natural analogs.

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5

Stutter, M. I., M. S. Alam, S. J. Langan, S. J. Woodin, R. P. Smart, and M. S. Cresser. "The effects of H2SO4 and (NH4)2SO4 treatments on the chemistry of soil drainage water and pine seedlings in forest soil microcosms." Hydrology and Earth System Sciences 8, no. 3 (June 30, 2004): 392–408. http://dx.doi.org/10.5194/hess-8-392-2004.

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Abstract. An experiment comparing effects of sulphuric acid and reduced N deposition on soil water quality and on chemical and physical growth indicators for forest ecosystems is described. Six H2SO4 and (NH4)2SO4 treatment loads, from 0 – 44 and 0 – 25 kmolc ha-1 yr-1, respectively, were applied to outdoor microcosms of Pinus sylvestris seedlings in 3 acid to intermediate upland soils (calc-silicate, quartzite and granite) for 2 years. Different soil types responded similarly to H2SO4 loads, resulting in decreased leachate pH, but differently to reduced N inputs. In microcosms of calc-silicate soil, nitrification of NH4 resulted in lower pH and higher cation leaching than in acid treatments. By contrast, in quartzite and granite soils, (NH4)2SO4 promoted direct cation leaching, although leachate pH increased. The results highlighted the importance of soil composition on the nature of the cations leached, the SO4 adsorption capacities and microbial N transformations. Greater seedling growth on calc-silicate soils under both treatment types was related to sustained nutrient availability. Reductions in foliar P and Mg with higher N treatments were observed for seedlings in the calc-silicate soil. There were few treatment effects on quartzite and granite microcosm tree seedlings since P limitation precluded seedling growth responses to treatments. Hence, any benefits of N deposition to seedlings on quartzite and granite soils appeared limited by availability of co-nutrients, exacerbated by rapid depletion of soil exchangeable base cations. Keywords: acidification, manipulation, nitrogen, ammonium, deposition, soil, drainage, pine, microcosms, forest

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6

Batchelor, Richard A. "Do Neoproterozoic (Moine) calc-silicate rocks represent metamorphosed tuffs? A geochemical re-appraisal." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 107, no. 4 (December 2016): 333–49. http://dx.doi.org/10.1017/s1755691018000063.

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ABSTRACTFollowing the identification of grey quartz–albite–chlorite–calcite–muscovite rocks in Meso- to Neo-proterozoic sequences in Scotland as metamorphosed tuffs of intermediate composition, it has been shown that this lithology will generate calc-silicate rocks at higher metamorphic grades. Both rock types occur as thin beds with sharp contacts with their host, occur as multiple beds in isolated suites, and share chemical compositions suggestive of volcanic sources with tholeiitic andesite affinities. The failure to recognise calc-silicate rocks as tuffs might explain the apparent scarcity of volcanogenic material through c.220 million years of early Earth history in Scotland.

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7

SATISH-KUMAR, M., and M. SANTOSH. "A petrological and fluid inclusion study of calc-silicate–charnockite associations from southern Kerala, India: implications for CO2 influx." Geological Magazine 135, no. 1 (January 1998): 27–45. http://dx.doi.org/10.1017/s0016756897008145.

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Recent discovery of wollastonite-bearing calc-silicate assemblages adjacent to gneiss–charnockite horizons in the supracrustal terrain of the Kerala Khondalite Belt, southern India, provides an opportunity to evaluate the carbonic fluid infiltration model proposed for charnockite formation. Petrological and fluid inclusion studies across these horizons in three representative localities are presented in this study. The calc-silicate assemblages define peak metamorphic conditions of ∼800°C at 5 kbar and define a low aCO2. Adjacent charnockite assemblages developed through dehydration involving the breakdown of garnet, biotite and quartz to produce orthopyroxene under low aH2O conditions. Retrograde reactions preserved in the calc-silicate rocks, such as scapolite–quartz symplectites, and the partial breakdown of wollastonite previously has been attributed to a near isothermal decompression during which infiltration of CO2-rich fluids occurred. Fluid inclusion studies indicate that the earliest generation of fluids preserved in the calc-silicate assemblages are aqueous (with salinity ∼8 wt% NaCl equivalent), consistent with mineral phase equilibria defining low aCO2. The estimation of NaCl content in brines coexisting with scapolite, based on the Cl content of the scapolite, indicates the presence of up to 20 wt % NaCl during the formation of scapolite consistent with the saline primary fluid inclusions. Primary carbonic inclusions occur within the retrogressed calcite+quartz assemblage after wollastonite, and are considered to represent the post-peak metamorphic carbonic fluid infiltration event, synchronous with the development of charnockites in the adjacent gneisses. These inclusions have identical characteristics to those in the charnockites. We envisage that the Kerala Khondalite Belt fluid regime was largely internally buffered during the prograde path, and that CO2 infiltration post-dated peak metamorphism. Influx of CO2 was mostly structurally controlled, and occurred along a near-isothermal uplift path. Graphite-bearing pegmatitic dykes with abundant CO2-rich inclusions in these localities attest to the transfer of carbonic fluids through magmatic conduits.

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8

Fonseca, Ariadne Do Carmo. "Fragmento tectónico cabo frio: aspectos de campo, petrografía e geoquímica." Anuário do Instituto de Geociências 17 (December 1, 1994): 109–31. http://dx.doi.org/10.11137/1994_0_109-131.

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The main lithological units which occur in the "Cabo Frio Tectonic Fragment" are orthogneisses and paragneisses. The orthogneisses have granitic-granodioritic-tonalitic compositions, with amphibolitic enclaves and intercalations and are cutted by granitic aplites. The paragneisses are metapelites, with intercalations of amphibolite, quartzites and calc-silicate rocks, metamorphosed in upper amphibolite facies, in intermediate pressure conditions. Geochemically, the orthogneisses correspond to a metaluminous high-K calc-alkalic series, with monzogabbro, quartz-monzodiorite and monzonite compositions. Otherwise, the petrography indicates a low-K calc-alkalic series, suggesting a pre-collisional granitoids series related to oceanic crust subduction. A divergence between the compositions obtained by the petrography and geochemistry can be the result of problems in the analyses of alkalies. The amphibolites, associated to the orthogneisses, also present calc-alkalic metaluminous character, with basaltic and andesitic compositions, suggestive of orogenic emplacement. The paragneisses show compositions varying between lithoarenite and arkoses, with peraluminous character, probably deposited in a continental are or ative continental margin environment.

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9

Birch, W. D. "Danburite‐bearing calc‐silicate rocks from the Ascot Hills, Dookie, Victoria." Australian Journal of Earth Sciences 43, no. 4 (August 1996): 387–93. http://dx.doi.org/10.1080/08120099608728262.

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10

Rolfo, Franco, Chiara Groppo, and Pietro Mosca. "Metamorphic CO2 production in calc-silicate rocks from the eastern Himalaya." Italian Journal of Geosciences 136, no. 1 (February 2017): 28–3. http://dx.doi.org/10.3301/ijg.2015.36.

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11

Braitenberg, Carla, and CK Shum. "Metamorphic CO2 production in calc-silicate rocks from the eastern Himalaya." Italian Journal of Geosciences 136, no. 1 (February 2017): 39–49. http://dx.doi.org/10.3301/ijg.2015.38.

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12

Shiraishi, Kazuyuki, Takanobu Oba, Morihisa Suzuki, and Ken’ichi Ishikawa. "Subsilicic magnesian potassium-hastingsite from the Prince Olav Coast, East Antarctica." Mineralogical Magazine 58, no. 393 (December 1994): 621–27. http://dx.doi.org/10.1180/minmag.1994.058.393.11.

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AbstractTwo subsilicic magnesian potassium-hastingsites (4.55 and 4.34 wt.% K2O) and one magnesian potassium-hastingsite occur in calc-silicate pods in well-layered gneisses from the transitional amphibolite- and granulite-facies terrain of a Cambrian metamorphic complex, East Antarctica. Subsilicic magnesian potassium-hastingsite is the most K-rich Ca-amphibole yet reported:

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13

LABORDA-LÓPEZ, CASTO, JULIO AGUIRRE, and STEPHEN K. DONOVAN. "SURVIVING METAMORPHISM: TAPHONOMY OF FOSSIL ASSEMBLAGES IN MARBLE AND CALC-SILICATE SCHIST." PALAIOS 30, no. 9 (September 2015): 668–79. http://dx.doi.org/10.2110/palo.2015.013.

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14

Newberry, R. J., J. T. Dillon, and D. D. Adams. "Regionally metamorphosed, calc-silicate-hosted deposits of the Brooks Range, northern Alaska." Economic Geology 81, no. 7 (November 1, 1986): 1728–52. http://dx.doi.org/10.2113/gsecongeo.81.7.1728.

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15

Sonnet, Philippe, Jean Verkaeren, and Gilbert Crevola. "Scheelite bearing calc-silicate gneisses in the Provence crystalline basement (Var, France)." Bulletin de Minéralogie 108, no. 3 (1985): 377–90. http://dx.doi.org/10.3406/bulmi.1985.7836.

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16

WARREN, R. G., B. J. HENSEN, and R. J. RYBURN. "Wollastonite and scapolite in Precambrian calc-silicate granulites from Australia and Antarctica." Journal of Metamorphic Geology 5, no. 2 (April 1987): 213–23. http://dx.doi.org/10.1111/j.1525-1314.1987.tb00380.x.

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17

Schmädicke, E., M. Okrusch, W. Schubert, B. Elwart, and U. Görke. "Phase relations of calc-silicate assemblagesin the Auerbach marble, OdenwaldCrystalline Complex, Germany." Mineralogy and Petrology 72, no. 1-3 (June 12, 2001): 77–111. http://dx.doi.org/10.1007/s007100170028.

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18

Kile, Daniel E., and Peter J. Modreski. "Mineralogy of a Calc-Silicate Locality near: Genesee Park, Jefferson County, Colorado." Rocks & Minerals 69, no. 5 (October 1994): 298–308. http://dx.doi.org/10.1080/00357529.1994.9925607.

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19

Patel, S. C. "Vesuvianite-wollastonite-grossular-bearing calc-silicate rock near Tatapani, Surguja district, Chhattisgarh." Journal of Earth System Science 116, no. 2 (April 2007): 143–47. http://dx.doi.org/10.1007/s12040-007-0014-6.

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20

Voudouris, P., I. Graham, K. Mavrogonatos, S. Su, K. Papavasiliou, M. V. Farmaki, and P. Panagiotidis. "MN-ANDALUSITE, SPESSARTINE, MN-GROSSULAR, PIEMONTITE AND MN-ZOISITE/CLINOZOISITE FROM TRIKORFO, THASSOS ISLAND, GREECE." Bulletin of the Geological Society of Greece 50, no. 4 (July 28, 2017): 2068. http://dx.doi.org/10.12681/bgsg.14258.

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Mylonitized manganiferous schists and calc-silicate layers intercalated within amphibolite- to greenschist facies mica schists from the Trikorfo area (Thassos Island, Greece), host an unusual Mn-rich paragenesis of metamorphic silicate minerals, most of them in large, gemmy crystals. The silicates occur both in layers subparallel to the foliation and within discordant veins cross-cutting the metamorphic fabric. Piemontite (up to 12.7 wt. % Mn2O3), Mn-rich epidote (up to 7.8 wt. % Mn2O3), Mn-rich andalusite (up to 15.6 wt. % Mn2O3), Mn-poor pink clinozoisite-epidote (up to 0.87 wt. % Mn2O3), Mn-poor pink zoisite (up to 0.21 wt. % Mn2O3), spessartine (up to 47.7 wt. % MnO) and Mn-rich grossular (up to 3.6 wt. % MnO) are associated with diopside, hornblende, phlogopite, muscovite, tourmaline, hematite and iron-bearing kyanite. The studied assemblages are indicative of high fO2 conditions due to the presence of highly oxidized pre-metamorphic Mn-rich mineral associations. They developed during prograde metamorphism of a Mn-rich sedimentary protolith(s), followed by re equilibration to post-peak metamorphic conditions, vein formation and metasomatism during retrograde metamorphism accompanying the exhumation of the Thassos Island during the Oligocene-Miocene. Alternatively, the skarn similar mineralogy of the calc-silicate layers could have been formed by fluids released by granitoids during contact metamorphism. The studied area represents a unique mineralogical geotope. Its geological-mineralogical heritage should be protected through establishment of a mineralogical-petrological geopark that will also promote sustainable development of the area.

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21

CRESPO, ELENA, JAVIER LUQUE, CARLOS FERNÁNDEZ-RODRÍGUEZ, MAGDALENA RODAS, MANUEL DÍAZ-AZPIROZ, JUAN CARLOS FERNÁNDEZ-CALIANI, and JOSÉ F. BARRENECHEA. "Significance of graphite occurrences in the Aracena Metamorphic Belt, Iberian Massif." Geological Magazine 141, no. 6 (November 2004): 687–97. http://dx.doi.org/10.1017/s0016756804009896.

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The significance of syngenetic and epigenetic graphite occurrences from the Variscan high-temperature/low-pressure Aracena Metamorphic Belt is discussed in the framework of the tectono-thermal evolution of this southern zone of the Iberian Massif. Syngenetic graphite is associated with both low- to medium-grade metamorphic rocks (La Umbría series, Precambrian in age) and high-grade, granulite facies rocks (the Precambrian Fuente del Oro series and a Cambrian calc-silicate series). Epigenetic, fluid-deposited occurrences correspond to overgrowths on existing metamorphic graphite grains and vein-type mineralization. Two types of graphitized particles with remarkable differences in reflectance, anisotropy and size can be distinguished in the Precambrian metapelites of the La Umbría series. Large, >150 μm length, platy crystals with high reflectance and anisotropy are interpreted as detrital and are considered indirect evidence of an old orogenic cycle prior to the Cadomian Orogeny, during which metamorphism exceeded greenschist facies. The coexistence of two types of particles explains the scattering of values of the c parameter of graphite determined by XRD (c = 6.72–6.74 Å), and the anomalously high temperatures of the DTA exothermic peak (close to 600 °C) of graphite with respect to that inferred from mineral assemblages in these rocks. The presence of graphite-rich quartzites and gneisses within the Fuente del Oro series and the calc-silicate series is evidence of sedimentation under reducing conditions in a continental shelf. The characteristics of graphite reflect the high-grade metamorphic conditions attained in the southern area of the Aracena Metamorphic Belt. Pervasive flow of fluids related to a major Variscan extensional event resulted in overgrowths on the pre-existing graphite in the gneisses and quartzites of the calc-silicate series, as evidenced by the heterogeneous isotopic composition of graphite single crystals in these rocks. A later stage of graphite precipitation is represented by scarce vein-type occurrences in mafic granulites that document channelled flow of fluids.

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22

Pan, Yuanming, and Michael E. Fleet. "Mineralogy and genesis of calc-silicates associated with Archean volcanogenic massive sulphide deposits at the Manitouwadge mining camp, Ontario." Canadian Journal of Earth Sciences 29, no. 7 (July 1, 1992): 1375–88. http://dx.doi.org/10.1139/e92-111.

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Skarn-like calc-silicate rocks are reported in spatial association with the Archean Cu–Zn–Ag massive sulphide deposits at the Manitouwadge mining camp, Ontario. Calc-silicates in the footwall of the Willroy mine occur as matrix to breccia fragments of garnetiferous quartzo-feldspathic gneiss and as lenses within garnetiferous quartzo-feldspathic gneiss and are composed of clinopyroxene, garnet, calcic amphiboles, wollastonite, plagioclase, K-feldspar, epidote, quartz, calcite, magnetite, and minor sulphides. Calc-silicates within the main orebody of the Geco mine are characterized by clinopyroxene, calcic amphiboles (Cl–K-rich hastingsitic and ferro-edenitic hornblende, ferro-edenite (up to 4.7 wt.% Cl); and ferroactinolite (6.7 wt.% MnO)), garnet, epidote (including an epidote rich in rare-earth elements and Cl), calcite, quartz, and abundant sulphides. Calc-silicates within the basal 4/2 Copper Zone of the Geco mine contain garnet, gahnite, sphalerite, ferroactinolite (8.5 wt.% MnO), epidote, quartz, biotite, plagioclase, chlorite, muscovite, K-feldspar, and pyrosmalite (with Mn/(Mn + Fe) ratio ranging from 0.21 to 0.61, and up to 3.9 wt.% Cl). The calc-silicates probably represent metasomatic remobilization of dispersed Ca (and Cl) from sea-floor hydrothermal alteration of mafic to intermediate volcanic rocks and are only indirectly related to the hypothesized syngenetic ore-forming processes for the associated base metal sulphide deposits. The calc-silicates formed initially at about 600 °C and 3–5 kbar (1 kbar = 100 MPa) in a mildly reducing environment (from 1 log unit above to 1 log unit below the fayalite–magnetite–quartz buffer) during the upper-amphibolite- to granulite-facies regional metamorphism and were altered subsequently at lower temperatures (<500 °C).

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23

Owens, Brent E. "High-temperature contact metamorphism of calc-silicate xenoliths in the Kiglapait Intrusion, Labrador." American Mineralogist 85, no. 11-12 (November 2000): 1595–605. http://dx.doi.org/10.2138/am-2000-11-1203.

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24

Ni, Huaiwei, and Li Zhang. "A general model of water diffusivity in calc-alkaline silicate melts and glasses." Chemical Geology 478 (February 2018): 60–68. http://dx.doi.org/10.1016/j.chemgeo.2017.10.010.

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25

Maitra, Monoj, and M. M. Korakoppa. "Tschermaks clinopyroxene-bearing calc-silicate skarn rock at Nirwand, Patcham Island, Kutchh, Gujarat." Journal of the Geological Society of India 80, no. 5 (November 2012): 609–12. http://dx.doi.org/10.1007/s12594-012-0187-8.

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26

Buick, Ian S., Simon L. Harley, and Ian C. Cartwright. "Granulite facies metasomatism: zoned calc-silicate boudins from the Rauer Group, East Antarctica." Contributions to Mineralogy and Petrology 113, no. 4 (1993): 557–71. http://dx.doi.org/10.1007/bf00698323.

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27

Luitel, Prakash, and Suman Panthee. "Geological study in Tal - Talekhu section of Manang District along the Besisahar – Chame Road." Bulletin of the Department of Geology 22 (December 15, 2020): 25–28. http://dx.doi.org/10.3126/bdg.v22i0.33411.

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The section between Tal to Talekhu of Manang District lacks the detailed geological study. The geological mapping in the scale of 1:50,000 followed by the preparation of geological cross-section and lithostratigraphic column has been done in the present study. The studied area lies partially in the Higher Himalayan Crystalline and the Tibetan Tethys Sequence. The units of the Higher Himalayan Group from Tal to Talekhu consists mainly of vigorous to faintly calcareous gneiss, migmatitic gneiss, quartzite, granite, etc. They are named as the Calc. Silicate Gneiss and Paragneiss and the Orthogneiss and Granite units. The lowermost part of the Tibetan Tethys consisted of metamorphosed calcareous rocks containing silicates and feldspar, so this unit is termed as the Marble and Calc. Gneiss. The section is about 9 km in thickness and is highly deformed with presence of igneous rocks at many places.

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Luitel, Prakash, and Suman Panthee. "Geological study in Tal - Talekhu section of Manang District along the Besisahar – Chame Road." Bulletin of the Department of Geology 22 (December 15, 2020): 25–28. http://dx.doi.org/10.3126/bdg.v22i0.33411.

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The section between Tal to Talekhu of Manang District lacks the detailed geological study. The geological mapping in the scale of 1:50,000 followed by the preparation of geological cross-section and lithostratigraphic column has been done in the present study. The studied area lies partially in the Higher Himalayan Crystalline and the Tibetan Tethys Sequence. The units of the Higher Himalayan Group from Tal to Talekhu consists mainly of vigorous to faintly calcareous gneiss, migmatitic gneiss, quartzite, granite, etc. They are named as the Calc. Silicate Gneiss and Paragneiss and the Orthogneiss and Granite units. The lowermost part of the Tibetan Tethys consisted of metamorphosed calcareous rocks containing silicates and feldspar, so this unit is termed as the Marble and Calc. Gneiss. The section is about 9 km in thickness and is highly deformed with presence of igneous rocks at many places.

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29

Mikhno, A. O., and A. V. Korsakov. "Carbonate, silicate, and sulfide melts: heterogeneity of the UHP mineral-forming media in calc-silicate rocks from the Kokchetav massif." Russian Geology and Geophysics 56, no. 1-2 (January 2015): 81–99. http://dx.doi.org/10.1016/j.rgg.2015.01.005.

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30

DASGUPTA, SOMNATH, and SUPRATIM PAL. "Origin of Grandite Garnet in Calc-Silicate Granulites: Mineral–Fluid Equilibria and Petrogenetic Grids." Journal of Petrology 46, no. 5 (January 28, 2005): 1045–76. http://dx.doi.org/10.1093/petrology/egi010.

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31

Munyanyiwa, Hubert, and Richard E. Hanson. "Geochemistry of marbles and calc-silicate rocks in the Pan-African Zambezi belt, Zambia." Precambrian Research 38, no. 3 (March 1988): 177–200. http://dx.doi.org/10.1016/0301-9268(88)90001-0.

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32

Amnatmetta, Bowornlak, John Booth, Prayath Nantasin, and Yoonsup Kim. "Metamorphic Evolution of Calc-silicate Rocks at Akarui Point, Lützow-Holm Complex, East Antarctica." IOP Conference Series: Earth and Environmental Science 837, no. 1 (August 1, 2021): 012008. http://dx.doi.org/10.1088/1755-1315/837/1/012008.

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33

Rodas, M., F. J. Luque, J. F. Barrenechea, J. C. Fernández-Caliani, A. Miras, and C. Fernández-Rodríguez. "Graphite occurrences in the low-pressure/high-temperature metamorphic belt of the Sierra de Aracena (southern Iberian Massif)." Mineralogical Magazine 64, no. 5 (October 2000): 801–14. http://dx.doi.org/10.1180/002646100549805.

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AbstractFour distinct associations of graphite have been identified in the low-pressure, high-temperature belt of the Sierra de Aracena (SW Spain). Syngenetic occurrences include: (1) stratiform graphite mineralization within a calc-silicate series; (2) disseminated graphite within a terrigenous sequence; and (3) ‘restitic’ graphite within anatectic tonalites and their enclaves. Epigenetic graphite occurs as (4) veins cross-cutting mafic granulites.Graphite in all types of occurrences is highly crystalline, with the c parameter close to 6.70 Å. Such c values correspond to temperatures of formation of ∼800°C. The thermal properties of graphite are also typical of well-ordered graphite and provide DTA exothermic maxima ranging from 810 to 858°C depending on the mode of occurrence. The differences among the temperatures of formation estimated by graphite geothermometry, the position of the exothermic maximum in the DTA curves, and petrologic geothermometers are discussed in terms of the applicability of graphite geothermometry to granulite-facies rocks. Carbon isotope analysis yields δ13C values in the range from −31.6 to −21.4% for syngenetic graphite of types I, II and III attributable to biogenically-derived carbon. The heavier signatures for graphite in vein occurrences (δ13C= −17.7 to −18.3%) with respect to syngenetic graphites suggest that isotopically heavy carbonic species were incorporated into the metamorphic fluids (probably as a consequence of decarbonation reactions of the calc-silicate rocks) from which graphite precipitated into the veins. These fluids were strongly channelled through structural pathways.

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34

Kontonikas-Charos, Alkis, Cristiana L. Ciobanu, Nigel J. Cook, Kathy Ehrig, Roniza Ismail, Sasha Krneta, and Animesh Basak. "Feldspar mineralogy and rare-earth element (re)mobilization in iron-oxide copper gold systems from South Australia: a nanoscale study." Mineralogical Magazine 82, S1 (February 28, 2018): S173—S197. http://dx.doi.org/10.1180/minmag.2017.081.040.

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ABSTRACTNanoscale characterization (TEM on FIB-SEM-prepared foils) was undertaken on feldspars undergoing transformation from early post-magmatic (deuteric) to hydrothermal stages in granites hosting the Olympic Dam Cu-U-Au-Ag deposit, and from the Cu-Au skarn at Hillside within the same iron-oxide copper-gold (IOCG) province, South Australia. These include complex perthitic textures, anomalously Ba-, Fe-, or REE-rich compositions, and REE-flourocarbonate + molybdenite assemblages which pseudomorph pre-existing feldspars. Epitaxial orientations between cryptoperthite (magmatic), patch perthite (dueteric) and replacive albite (hydrothermal) within vein perthite support interface-mediated reactions between pre-existing alkali-feldspars and pervading fluid, irrespective of micro-scale crystal morphology. Such observations are consistent with a coupled dissolution-reprecipitation reaction mechanism, which assists in grain-scale element remobilization via the generation of transient interconnected microporosity. Micro-scale aggregates of hydrothermal hyalophane (Ba-rich K-feldspar), crystallizing within previously albitized areas of andesine, reveal a complex assemblage of calc-silicate, As-bearing fluorapatite and Fe oxides along reaction boundaries in the enclosing albite-sericite assemblage typical of deuteric alteration. Such inclusions are good REE repositories and their presence supports REE remobilization at the grain-scale during early hydrothermal alteration. Iron-metasomatism is recognized by nanoscale maghemite inclusions within ‘red-stained’ orthoclase, as well as by hematite in REE-fluorocarbonates, which reflect broader-scale zonation patterns typical for IOCG systems. Potassium-feldspar from the contact between alkali-granite and skarn at Hillside is characterized by 100–1000 ppm REE, attributable to pervasive nanoscale inclusions of calc-silicates, concentrated along microfractures, or pore-attached. Feldspar replacement by REE-fluorcarbonates at Olympic Dam and nanoscale calc-silicate inclusions in feldspar at Hillside are both strong evidence for the role of feldspars in concentrating REE during intense metasomatism. Differences in mineralogical expression are due to the availability of associated elements. Lattice-scale intergrowths of assemblages indicative of Fe-metasomatism, REE-enrichment and sulfide deposition at Olympic Dam are evidence for a spatial and temporal relationship between these processes.

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35

DASGUPTA, S. "Contrasting mineral parageneses in high-temperature calc-silicate granulites: examples from the Eastern Ghats, India." Journal of Metamorphic Geology 11, no. 2 (March 1993): 193–202. http://dx.doi.org/10.1111/j.1525-1314.1993.tb00142.x.

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36

Labotka, Theodore C. "Evidence for immiscibility in Ti-rich garnet in a calc-silicate hornfels from northeastern Minnesota." American Mineralogist 80, no. 9-10 (October 1, 1995): 1026–30. http://dx.doi.org/10.2138/am-1995-9-1018.

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37

Chiarenzelli, Jeffrey, Marian Lupulescu, George Robinson, David Bailey, and Jared Singer. "Age and Origin of Silicocarbonate Pegmatites of the Adirondack Region." Minerals 9, no. 9 (August 23, 2019): 508. http://dx.doi.org/10.3390/min9090508.

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Silicocarbonate pegmatites from the southern Grenville Province have provided exceptionally large crystal specimens for more than a century. Their mineral parageneses include euhedral calc–silicate minerals such as amphibole, clinopyroxene, and scapolite within a calcite matrix. Crystals can reach a meter or more in long dimension. Minor and locally abundant phases reflect local bedrock compositions and include albite, apatite, perthitic microcline, phlogopite, zircon, tourmaline, titanite, danburite, uraninite, sulfides, and many other minerals. Across the Adirondack Region, individual exposures are of limited aerial extent (<10,000 m2), crosscut metasedimentary rocks, especially calc–silicate gneisses and marbles, are undeformed and are spatially and temporally associated with granitic pegmatites. Zircon U–Pb results include both Shawinigan (circa 1165 Ma) and Ottawan (circa 1050 Ma) intrusion ages, separated by the Carthage-Colton shear zone. Those of Shawinigan age (Lowlands) correspond with the timing of voluminous A-type granitic magmatism, whereas Ottawan ages (Highlands) are temporally related to orogenic collapse, voluminous leucogranite and granitic pegmatite intrusion, iron and garnet ore development, and pervasive localized hydrothermal alteration. Inherited zircon, where present, reflects the broad range of igneous and detrital ages of surrounding rocks. Carbon and oxygen isotopic ratios from calcite plot within a restricted field away from igneous carbonatite values to those of typical sedimentary carbonates and local marbles. Collectively, these exposures represent a continuum between vein-dyke and skarn occurrences involving the anatexis of metasedimentary country rocks. Those of Ottawan age can be tied to movement and fluid flow along structures accommodating orogenic collapse, particularly the Carthage-Colton shear zone.

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38

Anticoi, Hernan, Eduard Guasch, Sarbast Ahmad Hamid, Josep Oliva, Pura Alfonso, Marc Bascompta, Lluis Sanmiquel, et al. "An Improved High-Pressure Roll Crusher Model for Tungsten and Tantalum Ores." Minerals 8, no. 11 (October 25, 2018): 483. http://dx.doi.org/10.3390/min8110483.

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An improved approach is presented to model the product particle size distribution resulting from grinding in high-pressure roll crusher with the aim to be used in standard high-pressure grinding rolls (HPGR). This approach uses different breakage distribution function parameter values for a single particle compression condition and a bed compression condition. Two materials were used for the experiments; altered Ta-bearing granite and a calc-silicate tungsten ore. A set of experiments was performed with constant operative conditions, while varying a selected condition to study the influence of the equipment set-up on the model. The material was comminuted using a previously determined specific pressing force, varying the feed particle size, roll speed and the static gap. A fourth group of experiments were performed varying the specific pressing force. Experimental results show the high performance of the comminution in a high-pressure environment. The static gap was the key in order to control the product particle size. A mathematical approach to predict the product particle size distribution is presented and it showed a good fit when compared to experimental data. This is the case when a narrow particle size fraction feed is used, but the fit became remarkably good with a multi-size feed distribution. However, when varying the specific pressing force in the case of the calc-silicate material, the results were not completely accurate. The hypothesis of simultaneous single particle compression and bed compression for different size ranges and with different parameters of the distribution function was probed and reinforced by various simulations that exchanged bed compression parameters over the single particle compression distribution function, and vice versa.

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39

Shatsky, V. S., A. L. Ragozin, S. Yu Skuzovatov, O. A. Kozmenko, and E. Yagoutz. "Isotope-Geochemical Evidence of the Nature of the Protoliths of Diamondiferous Rocks of the Kokchetav Subduction–Collision Zone (Northern Kazakhstan)." Russian Geology and Geophysics 62, no. 5 (May 1, 2021): 547–56. http://dx.doi.org/10.2113/rgg20204278.

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Abstract —The isotope-geochemical features of diamondiferous metamorphic rocks of the Kokchetav subduction–collision zone (KSCZ) show that both the basement rocks and the sediments of the Kokchetav massif were their protoliths. A whole-rock Sm–Nd isochron from the diamondiferous calc-silicate, garnet–pyroxene rocks and migmatized granite-gneisses of the western block of the KSCZ yielded an age of 1116 ± 14 Ma, while an age of 1.2–1.1 Ga was obtained by U–Pb dating of zircons from the granite-gneiss basement of the Kokchetav microcontinent. Based on these data, we assume that the protoliths of the calc-silicate, garnet–pyroxene rocks and the granite-gneisses of the KSCZ were the basement rocks sharing an initially single Nd source, which was not influenced by high- to ultrahigh-pressure metamorphism (~530 Ma). Therefore, their geochemical features are probably not directly related to ultrahigh-pressure metamorphism. The corresponding rock associations lack isotope-geochemical evidence of partial melting that would occur during ultrahigh-pressure metamorphism, which suggesting that they were metamorphosed under granulite-facies conditions. At the same time, the high-alumina diamondiferous rocks of the Barchi area (garnet–kyanite–mica schists and granofelses), which were depleted to different degrees in light rare-earth elements (REE) and K, have yielded a Sm–Nd whole-rock isochron age of 507 ± 10 Ma indicating partial melting of these rocks during their exhumation stage. The close ɛNd (1100) values of the basement rocks and garnet–kyanite–mica schist with geochemical characteristics arguing against its depletion during high-pressure metamorphism indicate that the basement rocks were a crustal source for high-alumina sediments.

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40

Owens, B. E., and D. T. Kremser. "AKERMANITE BREAKDOWN TO A CUSPIDINE-BEARING SYMPLECTITE IN A CALC-SILICATE XENOLITH, KIGLAPAIT INTRUSION, LABRADOR, CANADA." Canadian Mineralogist 48, no. 4 (August 1, 2010): 809–19. http://dx.doi.org/10.3749/canmin.48.4.809.

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41

Taguchi, T., M. Satish-Kumar, T. Hokada, and M. Jayananda. "PETROGENESIS OF Cr-RICH CALC-SILICATE ROCKS FROM THE BANDIHALLI SUPRACRUSTAL BELT, ARCHEAN DHARWAR CRATON, INDIA." Canadian Mineralogist 50, no. 3 (June 1, 2012): 705–18. http://dx.doi.org/10.3749/canmin.50.3.705.

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42

MAKI, K., Y. FUKUNAGA, T. NISHIYAMA, and Y. MORI. "ProgradeP-Tpath of medium-pressure granulite facies calc-silicate rocks, Higo metamorphic terrane, central Kyushu, Japan." Journal of Metamorphic Geology 27, no. 2 (February 2009): 107–24. http://dx.doi.org/10.1111/j.1525-1314.2008.00808.x.

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43

Satish-Kumar, M., M. Santosh, S. L. Harley, and M. Yoshida. "Calc-silicate assemblages from the Kerala Khondalite Belt, southern India: implications for pressure-temperature-fluid histories." Journal of Southeast Asian Earth Sciences 14, no. 3-4 (October 1996): 245–63. http://dx.doi.org/10.1016/s0743-9547(96)00062-1.

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44

Morand, V. J. "Geological note: Calc‐silicate lenses in the early Palaeozoic mud‐pile of the Lachlan fold belt." Australian Journal of Earth Sciences 41, no. 4 (August 1994): 383–86. http://dx.doi.org/10.1080/08120099408728147.

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45

HOLNESS, M. B. "Metamorphism and Fluid Infiltration of the Calc-silicate Aureole of the Beinn an Dubhaich Granite, Skye." Journal of Petrology 33, no. 6 (December 1, 1992): 1261–93. http://dx.doi.org/10.1093/petrology/33.6.1261.

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46

Akolkar, Gayatri, and M. A. Limaye. "Mineral Chemistry and Reaction Textures of Calc-silicate Rocks of the Lunavada Region, SAMB, NE Gujarat." Journal of the Geological Society of India 97, no. 2 (February 2021): 151–57. http://dx.doi.org/10.1007/s12594-021-1646-x.

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47

Moazzen, Mohssen, Roland Oberhänsli, Robab Möller Hajialioghli, Romain Bousquet, Giles Droop, and Ahmad Jahangiri. "Peak and post-peak PT conditions and fluid composition for scapolite-clinopyroxene-garnet calc-silicate rocks from the Takab area, NW Iran." European Journal of Mineralogy 21, no. 1 (February 6, 2009): 149–62. http://dx.doi.org/10.1127/0935-1221/2009/0021-1887.

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48

Mikhno, Anastasia O., Ute Schmidt, and Andrey V. Korsakov. "Origin of K-cymrite and kokchetavite in the polyphase mineral inclusions from Kokchetav UHP calc-silicate rocks: evidence from confocal Raman imaging." European Journal of Mineralogy 25, no. 5 (January 16, 2014): 807–16. http://dx.doi.org/10.1127/0935-1221/2013/0025-2321.

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49

Voudouris, P., S. Constantinidou, M. Kati, C. Mavrogonatos, C. Kanellopoulos, and E. Volioti. "Genesis of alpinotype fissure minerals from Thasos Island, Northern Greece - Mineralogy, mineral chemistry and crystallizing environment." Bulletin of the Geological Society of Greece 47, no. 1 (September 5, 2013): 468. http://dx.doi.org/10.12681/bgsg.11024.

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Alpinotype fissure-minerals in Thasos Island are hosted in gneisses, amphibolites, Mn-rich schists and calc-silicate layers, and marbles of the Carboniferous-Permian Pangeon Unit, which represents the lower tectonostratigraphic unit of the southern Rhodope metamorphic core complex. Alpinotype fissures crosscut metamorphic fabrics and are closely related to the exhumation processes of the core complex during the Oligocene-Miocene. Most mineralized fissures occur close to a major detachment fault, which separates gneisses from marbles and amphibolites. The mineralogy of the alpinotype fissures is closely related to the host rocks: amphibolite-hosted fissures include adularia, albite, quartz, titanite, apatite, actinolite, chlorite, calcite, hematite and rutile. Fissures in para- and orthogneisses- and in metapegmatites are characterized by smoky and clear quartz, adularia, muscovite and hematite. Fissures within spessartite-piemontite schists contain quartz, chlorite, spessartite, hematite, rutile, albite, epidote and traces of zircon. Finally fissures in calc-silicate layers include Mn-grossular, quartz and Mn-clinozoisite. Hydrothermal alteration halos surrounding the fissures may suggest leaching of the wall rocks as a potential mechanism for mineral deposition. Scepter quartz crystals consist of a lower Tessinhabit crystal and several generations of upper prismatic quartz crystals, suggesting several stages of crystallization and changing P-T-x conditions with time. Chlorite geothermometry indicates temperatures of formation in the range between 286 and 366 °C. Tessin habit quartz was deposited from CO2-bearing fluids, probably at the transition from a compressional to an extensional tectonic regime and was later dissolved by meteoric water dominated fluids resulting in the formation of quartz scepters. Oxidizing conditions are indicated by the widespread occurrence of hematite in the mineralization. The studied area represents a unique mineralogical geotope. Its geological-mineralogical heritage should be protected through establishment of a mineralogical-petrological geopark that will also promote sustainable development of the area.

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50

Muszer, Antoni, Adam Szuszkiewicz, and Krzysztof Łobos. "New Occurrence of Clausthalite (PbSe) in the Sudetes (SW Poland)." Mineralogia 37, no. 2 (January 1, 2006): 123–32. http://dx.doi.org/10.2478/v10002-007-0010-0.

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New Occurrence of Clausthalite (PbSe) in the Sudetes (SW Poland)The presence of clausthalite in the area of old mining works near Dziećmorowice in the Sowie Mts (SW Poland) is reported here for the first time. The identification of the clausthalite is based on macro- and microscopic observations, reflectance measurements, chemical analyses and X-ray diffraction data. The clausthalite, together with uraninite, forms veinlets in a breccia comprising <50% calc-silicate rock fragments. Different polishing hardnesses suggest some variation in the mineral structure of individual clausthalite grains. Chemical spot analyses do not reveal elements other than Pb and Se though calculated unit-cell parameters may suggest minor substitution of S for Se.

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