Margarite-corundum phyllites from the Appalachian orogen of South Carolina: Mineralogy and metamorphic history
-
William A. Ranson
Abstract
Phyllites from the Charlotte belt (Central Piedmont) of South Carolina contain porphyroblasts of black corundum in a matrix of margarite and minor muscovite. The margarite-corundum phyllites formed during Ordovician (?) amphibolite facies metamorphism of an aluminous protolith with a probable mineralogy of pyrophyllite, diaspore, and calcite through reactions such as 6Dia + Prl + 2Cal = 2Mrg + 2CO2 + 2H2O and 2Dia = Crn + H2O. The protolith was probably a hydrothermally altered felsic tuff of Late Proterozoic to Cambrian age. Based on a whole-rock chemical analysis of margarite-corundum phyllite, the protolith is believed to have consisted of about 7 mol% calcite, 23 mol% pyrophyllite, and 70 mol% diaspore. A T-XCO2 plot of pertinent reactions in the system CaOAl2O3- SiO2-H2O-CO2 shows that in the presence of an H2O-rich fluid (XCO2~0.08) margarite began forming by the reaction 6Dia + Prl + 2Cal = 2Mrg + 2CO2 + 2H2O at about 350 °C at 5 kbar. This reaction continued along a univariant path until pyrophyllite and calcite were consumed. The remaining diaspore was converted to corundum by the reaction 2Dia = Crn + H2O at about 430 °C for this H2O-rich fluid at 5 kbar. The upper temperature limit of this assemblage is constrained by the reaction Mrg = Crn + An + H2O, which should occur at about 575 °C under this pressure. The absence of plagioclase in these rocks suggests that the conditions of this reaction were never achieved. Fluids associated with subsequent Alleghanian greenschist facies metamorphism reacted with corundum to form fine-grained margarite at corundum margins
© 2015 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Patterns of mineral occurrence in metamorphic rocks
- A double magmatic heat pump at the core-mantle boundary
- High-temperature contact metamorphism of calc-silicate xenoliths in the Kiglapait Intrusion, Labrador
- Multiple pyroxene and amphibole assemblages in the amphibolite facies: Bulk compositional controls
- Margarite-corundum phyllites from the Appalachian orogen of South Carolina: Mineralogy and metamorphic history
- Continuous metamorphic gradient documented by graphitization and K-Ar age, southeast Otago, New Zealand
- Kyanite eclogite thermobarometry and evidence for thrusting of UHP over HP metamorphic rocks, Nordøyane, Western Gneiss Region, Norway
- Monazite geochronology of UHP and HP metamorphism, deformation, and exhumation, Nordøyane, Western Gneiss Region, Norway
- Solubilities of noble metals in Fe-containing silicate melts as derived from experiments in Fe-free systems
- Water speciation in silicate glasses and melts: Langmuir limited site model
- The ab initio study of the stability of low temperature Al/Si ordered albite, NaAlSi3O8
- The heat capacity of MgCr2O4, FeCr2O4, and Cr2O3 at low temperatures and derived thermodynamic properties
- Thermodynamics of the R3̅ to R3̅c phase transition in the ilmenite-hematite solid solution
- An ab initio study of hydrogarnets
- Short-range order in synthetic aluminous tremolites: An infrared and triple-quantum MAS NMR study
- In-situ Raman spectroscopy of quartz: A pressure sensor for hydrothermal diamond-anvil cell experiments at elevated temperatures
- Modification of the hydroxyl surface of potassium acetate intercalated halloysite between 25 and 300 °C
- On the occurrence of anomalous fission tracks in apatite and titanite
- Reactivity of surface sites on fractured arsenopyrite (FeAsS) toward oxygen
- Surface area and porosity of primary silicate minerals
- Charge contrast imaging of geological materials in the environmental scanning electron microscope
- Chemical fine structure of Franciscan jadeitic pyroxene from Ward Creek, Cazadero area, California
- Crystal structure of CaMg2Al6O12, a new Al-rich high pressure form
- The crystal structure of “Tetragonal Almandine-Pyrope Phase” (TAPP): A reexamination
- The crystal structure of tetranatrolite from Mont Saint-Hilaire, Québec, and its chemical and structural relationship to paranatrolite and gonnardite
- Elyite, Pb4Cu(SO4)O2(OH)4·H2O: Crystal structure and new data
- Dukeite, Bi3+24Cr86+O57(OH)6(H2O)3, a new mineral from Brejaúba, Minas Gerais, Brazil: Description and crystal structure
- Pseudosinhalite is a structural isotype of chondrodite
- Structure type and bulk modulus of Fe3S, a new iron-sulfur compound
- Single crystal elasticity of lawsonite
- In situ measurement of viscosity of liquids in the Fe-FeS system at high pressures and temperatures
Artikel in diesem Heft
- Patterns of mineral occurrence in metamorphic rocks
- A double magmatic heat pump at the core-mantle boundary
- High-temperature contact metamorphism of calc-silicate xenoliths in the Kiglapait Intrusion, Labrador
- Multiple pyroxene and amphibole assemblages in the amphibolite facies: Bulk compositional controls
- Margarite-corundum phyllites from the Appalachian orogen of South Carolina: Mineralogy and metamorphic history
- Continuous metamorphic gradient documented by graphitization and K-Ar age, southeast Otago, New Zealand
- Kyanite eclogite thermobarometry and evidence for thrusting of UHP over HP metamorphic rocks, Nordøyane, Western Gneiss Region, Norway
- Monazite geochronology of UHP and HP metamorphism, deformation, and exhumation, Nordøyane, Western Gneiss Region, Norway
- Solubilities of noble metals in Fe-containing silicate melts as derived from experiments in Fe-free systems
- Water speciation in silicate glasses and melts: Langmuir limited site model
- The ab initio study of the stability of low temperature Al/Si ordered albite, NaAlSi3O8
- The heat capacity of MgCr2O4, FeCr2O4, and Cr2O3 at low temperatures and derived thermodynamic properties
- Thermodynamics of the R3̅ to R3̅c phase transition in the ilmenite-hematite solid solution
- An ab initio study of hydrogarnets
- Short-range order in synthetic aluminous tremolites: An infrared and triple-quantum MAS NMR study
- In-situ Raman spectroscopy of quartz: A pressure sensor for hydrothermal diamond-anvil cell experiments at elevated temperatures
- Modification of the hydroxyl surface of potassium acetate intercalated halloysite between 25 and 300 °C
- On the occurrence of anomalous fission tracks in apatite and titanite
- Reactivity of surface sites on fractured arsenopyrite (FeAsS) toward oxygen
- Surface area and porosity of primary silicate minerals
- Charge contrast imaging of geological materials in the environmental scanning electron microscope
- Chemical fine structure of Franciscan jadeitic pyroxene from Ward Creek, Cazadero area, California
- Crystal structure of CaMg2Al6O12, a new Al-rich high pressure form
- The crystal structure of “Tetragonal Almandine-Pyrope Phase” (TAPP): A reexamination
- The crystal structure of tetranatrolite from Mont Saint-Hilaire, Québec, and its chemical and structural relationship to paranatrolite and gonnardite
- Elyite, Pb4Cu(SO4)O2(OH)4·H2O: Crystal structure and new data
- Dukeite, Bi3+24Cr86+O57(OH)6(H2O)3, a new mineral from Brejaúba, Minas Gerais, Brazil: Description and crystal structure
- Pseudosinhalite is a structural isotype of chondrodite
- Structure type and bulk modulus of Fe3S, a new iron-sulfur compound
- Single crystal elasticity of lawsonite
- In situ measurement of viscosity of liquids in the Fe-FeS system at high pressures and temperatures
