High-magnesium staurolite in a sapphirine-garnet rock from the Limpopo Belt, Southern Africa

Schreyer, Werner; Horrocks, Peter C.; Abraham, K.

doi:10.1007/bf00381847

Cited by 44 publications

(15 citation statements)

References 14 publications

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“…Schreyer & Abraham, 1976;Horrocks, 1983b; Windley et ul., Schreyer, Horrocks & Abraham, 1984). The sapphirine granulites described here were collected from Europe Claim, 13 km north of Beitbridge on the West Nicholson road.…”

Section: Petrographymentioning

confidence: 93%

Reaction history of garnet‐sapphirine granulites and conditions of Archaean high‐pressure granulite‐facies metamorphism in the Central Limpopo Mobile Belt, Zimbabwe

Droop

1989

Journal Metamorphic Geology

100

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Sequential reaction textures in Archaean garnet-corundum-sapphirine granulites from the Central Zone of the Limpopo Belt document a progression from early, coarse-grained, high-pressure (P '9.5 kbar) granulite-facie assemblages (Ml) to late, low-pressure (P < 6 kbar) granulite-facies sub-assemblagesThe stable M1 assemblage was garnet (57% pyrope; Mg/(Mg + Fe) = 62) + sapphirine + corundum + gedrite+phlogopite+rutile. Late-M1 boron-free kornerupine grew at the expense of garnet and corundum, and coexisted with garnet, sapphirine and gedrite. Partial or complete breakdown of coarse garnet and komerupine during h42 resulted in the development of pseudomorphs and coronas consisting of fine-grained symplectic intergrowths of cordiente, gedrite and sapphirine (later, spinel).The majority of reaction textures can be explained in terms of a stable reaction sequence, and a model time-sequence of mineral facies can be constructed. When compared with a qualitative petrogenetic grid of (Fe, Mg)-discontinuous reactions in the FMASH multisystem sapphirine-garnet-corundum-spinelcordierite-gedrite-kornerupine, the facies-sequence indicates decompression at essentially constant T assuming constant u(H,O).Exhumation of M1 corundum inclusions during A42 breakdown of kornerupine resulted in production of metastable spinel by a disequilibrium reaction with gedrite. A second disequilibrium reaction of the spinel with cordierite produced sapphirine. The operation of such reaction while pressure was decreasing (the opposite dP from that implied by the texture if assumed to be the product of an equilibrium reaction) has serious implications for the use of reaction textures in the construction of P-T vectors.Garnet-biotite thermometry on garnet interiors and phlogopite inclusions in corundum yields temperatures of cu. 850" C for the M1 stage. A minimum late-M1 pressure of cu. 7 kbar is indicated by the former association of kornerupine and corundum. Relict M1 kyauites reported by other workers indicate a minumum early-Ml pressure of 9.5 kbar, implying metamorphism at depths of at least 33 km (probably ~3 8 k m ) . The high-pressure granulite-facies metamorphism was followed by an almost isothermal pressure decrease of >5 kbar, indicative of rapid uplift. The P-7' path is interpreted as the product of a single metamorphic cycle which probably took place in response to tectonic thickening of the crust. Such a process contrasts with the extensional origin recently proposed for isobaridly cooled granulite-facies terranes.

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Section: Petrographymentioning

confidence: 93%

Reaction history of garnet‐sapphirine granulites and conditions of Archaean high‐pressure granulite‐facies metamorphism in the Central Limpopo Mobile Belt, Zimbabwe

Droop

1989

Journal Metamorphic Geology

100

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“…The staurolite occurs as inclusions in garnet or aggregates with gedrite. Staurolite with X Mg > 0.5 has been reported from ultrahigh-pressure (UHP) and eclogite-facies rocks (e.g., Enami and Zang, 1988;Peacock and Goodge, 1995) and also rarely from HP granulites (e.g., Schreyer et al, 1984;Tsunogae and van Reenen, 2006). Shimpo et al (2006) and Tsunogae and Santosh (2006b) pointed out that such Mg-rich staurolite from the PCSZ is an evidence for prograde HP metamorphism based on the experimental investigations of Mg-staurolite (Schreyer, 1988;Fockenberg, 1998) and the thermodynamic calculations involving Fe-staurolite (Ganguly, 1972;Grew, 1986).…”

Section: High-pressure Metamorphism Of Northern Madurai Blockmentioning

confidence: 99%

High-pressure and ultrahigh-temperature metamorphism at Komateri, northern Madurai Block, southern India

Tsunogae

Santosh

Ohyama

et al. 2008

Journal of Asian Earth Sciences

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“…Representative Raman spectra of host garnet and inclusion minerals. ing progeade stage (Schreyer et al, 1984;Tsunogae and van Reenen, 2006).…”

Section: Prograde Metamorphismmentioning

confidence: 99%

A petrologic and laser Raman spectroscopic study of sapphirine–spinel–quartz–Mg-staurolite inclusions in garnet from Kumiloothu, southern India: Implications for extreme metamorphism in a collisional orogen

Sato

Santosh

Tsunogae

2009

Journal of Geodynamics

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High-magnesium staurolite in a sapphirine-garnet rock from the Limpopo Belt, Southern Africa

Cited by 44 publications

References 14 publications

Reaction history of garnet‐sapphirine granulites and conditions of Archaean high‐pressure granulite‐facies metamorphism in the Central Limpopo Mobile Belt, Zimbabwe

Reaction history of garnet‐sapphirine granulites and conditions of Archaean high‐pressure granulite‐facies metamorphism in the Central Limpopo Mobile Belt, Zimbabwe

High-pressure and ultrahigh-temperature metamorphism at Komateri, northern Madurai Block, southern India

A petrologic and laser Raman spectroscopic study of sapphirine–spinel–quartz–Mg-staurolite inclusions in garnet from Kumiloothu, southern India: Implications for extreme metamorphism in a collisional orogen

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