High-temperature contact metamorphism of calc-silicate xenoliths in the Kiglapait Intrusion, Labrador
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Brent E. Owens
Abstract
Calc-silicate xenoliths occur as part of a xenolith and autolith swarm in the Lower Zone of the Kiglapait Intrusion, Labrador. All xenoliths are lighter-colored than the local troctolite host rock, and are surrounded by a 1-2 cm thick reaction zone of clinopyroxenite. The typical mineral assemblage in calc-silicate xenoliths is diopside + forsterite + monticellite + spinel, and one also contains åkermanite. Reaction zones are dominated by diopside and spinel. All clinopyroxene compositions are “fassaitic,” with high concentrations of Al2O3 (4-12 wt%), TiO2 (1-4 wt%), and calculated Fe2O3 (Fe3+ > Fe2+). In addition, clinopyroxene grains locally display extreme zoning in Si, Al, Ti, and XMg. Åkermanite contains up to 1.5 wt% Na2O.
Textures in the xenoliths are complex, with most containing highly irregular intergrowths of diopside, forsterite, and monticellite. Åkermanite and forsterite are separated locally by a coarse symplectic intergrowth of diopside and monticellite, which resulted from a retrograde reaction. The dominant assemblage probably represents the production of monticellite from calcite + clinopyroxene + forsterite, until calcite was consumed. These reactions require metamorphic temperatures of ~900 °C and pressures ≤ 0.4 kbar, such that the xenoliths were probably derived from the roof of the magma chamber. Whole-rock compositions reflect either substantial chemical exchange with the Kiglapait magma, or a very impure dolomitic protolith. The clinopyroxenite reaction zones were produced primarily by assimilation of carbonate by the Kiglapait magma, in combination with the effects of magma undercooling near the xenoliths
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- 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
Articles in the same Issue
- 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
