GPT: An excel spreadsheet for thermobarometric calculations in metapelitic rocks

Reche, J.; Martínez, Francisco J.

doi:10.1016/0098-3004(96)00007-6

Cited by 67 publications

(41 citation statements)

References 41 publications

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“…Kohn and Spear (1999) Reche and Martinez (1996) TWEEQU Berman (1991) Grt-Bt The estimated pressure and temperature data calculated with THERMOCALC (8.4-11.1 kbar and 900-1000 °C, Table 7) retrieve the metamorphic peak at ultrahigh-temperature conditions. For the temperature interval of 900-1000 °C, the different calibrations of the geobarometer Opx-Grt-Pl-Qz (Bhattacharya et al, 1991) lead to pressure that are compatible with those obtained by THERMOCALC.…”

Section: Samples Softwares/ Methodsmentioning

confidence: 99%

“…According to Hensen (1986) and Bertrand et al (1991), the assemblage Opx-Sil-Grt-Qtz should indicate pressures higher than 11 kbar. In order to constrain the temperature-pressure metamorphic conditions in the sapphirine-bearing granulite and the tonalitic orthogneiss, using the compositions of the cores of the grains, the thermobarometry programs by Kohn and Spear (1999), Reche and Martinez (1996), Berman (1991) and Holland and Powell (1998) were used ( Table 7). The first two are EXCEL spreadsheets for thermobarometric calculations applied to metapelites and based on calibrations by different authors.…”

Section: Thermobarometry Microstructures Relations and P-t Pathmentioning

confidence: 99%

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Metamorfismo de temperatura ultra-alta de granulitos com safirina de 2,0 Ga do Bloco Itabuna-Salvador-Curaçá, Bahia, Brasil

Barbosa

Leal

Fuck

et al. 2017

Geol. USP. Sér. Cient.

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A área de pesquisa se situa no Cráton do São Francisco, no sul da Bahia, Brasil. Nessa região, no segmento crustal Bloco Itabuna-Salvador-Curaçá (BISC), ocorrem rochas supracrustais associadas a gnaisses tonalíticos/trondhjemíticos a monzoníticos e rochas máficas subordinadas, de idades arqueana e paleoproterozoica, todos fortemente deformados e reequilibrados na fácies granulito em 2,07 a 2,08 Ga. As rochas supracrustais incluem granulitos com safirina constituídos por quartzo, ortopiroxênio, silimanita, granada, mesopertita, plagioclásio, biotita e cordierita. Com base nos arranjos microestruturais entre os minerais constituintes dos granulitos com safirina, a paragênese de pico metamórfico é Grt1 + Opx1 + Bt1 + Qtz + Sil1 + Spr1 + Mp. Microestruturas de reações entre minerais, como coroas de simplectitos ao redor de porfiroblastos, permitiram identificar as seguintes paragêneses retrógradas, interpretadas como formadas durante a ascensão tectônica dessas rochas: Grt1 ± Qtz = Opx2 + Sil2, Grt1 = Opx2 + Spr2 (+ Sil2); Opx1 + Sil1 + Qtz = Crd e Grt1 + Qtz = Opx3 + Crd. Por sua vez, simplectitos de Bt2 + Qtz formados pela reação Opx1-2 + Mp + H2O = Bt2 + Qtz estão relacionados à evolução retrógrada durante resfriamento. Cálculos termobarométricos realizados com aplicação de termobarômetros clássicos e método de multiequilíbrios (THERMOCALC, por exemplo) indicaram P = 7-11 kbar e T ≥ 900°C para os granulitos com safirina. Um dos mecanismos associados à elevada temperatura está relacionado à adição de material radioativo com a presença de magmas basálticos durante a formação do BISC. A cristalização fracionada desses magmas produziu intrusões tonalíticas que datam de aproximadamente de 2,15 a 2,13 Ga, próximo do pico do metamorfismo de 2,07 a 2,08 Ga.

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Section: Samples Softwares/ Methodsmentioning

confidence: 99%

Section: Thermobarometry Microstructures Relations and P-t Pathmentioning

confidence: 99%

Metamorfismo de temperatura ultra-alta de granulitos com safirina de 2,0 Ga do Bloco Itabuna-Salvador-Curaçá, Bahia, Brasil

Barbosa

Leal

Fuck

et al. 2017

Geol. USP. Sér. Cient.

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“…Lower PT estimates are based on microprobe data of two samples (shown in Fig 3c&d) of garnet-sillimanite-cordierite gneiss with minor biotite, K-feldspar, plagioclase and green hercynite spinel, from the central part of the Choum-Rag El Abiod Terrane. The microprobe data were run through GPT, an Excel spreadsheet for thermobarometric calculations in metapelitic rocks (Reche & Martinez, 1996). The key minerals are not significantly zoned and are apparently well suited to quantitative P-T estimation.…”

Section: Tectono-thermal Eventsmentioning

confidence: 99%

Two Mesoarchaean terranes in the Reguibat shield of NW Mauritania

Key

Loughlin

Gillespie

et al. 2008

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“…Metamorphism during D 2 was still within the stability field of sillimanite, but only a few quantitative P-T estimates could be calculated from D 3 equilibria. Two P-T estimates from the spreadsheet GPT (Reche & Martinez 1996), and one from a calculation of average P-T from AX-THERMOCALC (Powell et al 1998) were the only calculations possible from the range of D 3 assemblages within the gneiss. Two of the estimates are a comparison of GPT and AX-THERMOCALC methods from sample ps157-159.…”

Section: And D 2 Metasomatismmentioning

confidence: 99%

VEIN AND SKARN FORMATION AT THE CANNINGTON Ag Pb Zn DEPOSIT, NORTHEASTERN AUSTRALIA

Roache¹,

Williams²,

Richmond³

et al. 2005

The Canadian Mineralogist

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Synchronous deformation and metamorphism at the Cannington Ag-Pb-Zn deposit, in northeastern Australia, involved a phase of Ca and Mn mobilization that accounts for the distribution of pyroxene-and garnet-bearing rocks, which were preferentially overprinted by sulfide mineralization. Garnet composition and its textural association in relation to three generations of planar fabric (S 1 to S 3 ) show that skarn-related grossular-rich garnet formed in the last garnet-stable event, D 3 . The D 3 Cl-rich biotite in the gneiss is intergrown with garnet in veins, and within skarn rocks is continuous along strike with veins of garnet ± pyroxmangite, hedenbergite or amphibole, which indicates a period of anhydrous through to hydrous metasomatism. Compositional maps show that infiltration extended from alteration fronts through fractures, which indicates the high permeability of S 3 ; these maps and X Grt profiles across skarn-gneiss contacts show that there was large-scale transport of mass by infiltration and varying degrees of hydrodynamic dispersion. Precipitation of oscillatory Ca-and Mn-zoned grossular-rich garnet in veins parallel to veins filled with Cl-rich biotite, in conjunction with the distribution of biotite-filled veins across the deposit, suggest that the mass transfer during D 3 may be responsible for deposit-scale Ca-Mn skarn-like zoning.Keywords: garnet, zoning, metasomatism, skarn, shear zones, veins, Cannington, Australia. SOMMAIREUne déformation et une recristallisation métamorphique synchrones dans le gisement à Ag-Pb-Zn de Cannington, dans le nord-est de l'Australie, a impliqué une mobilisation de Ca et de Mn qui rend compte de la distribution de roches à pyroxène et grenat, qui sont devenues par la suite les hôtes ciblés d'une minéralisation en sulfures. La composition et l'association texturale du grenat aux trois générations de foliation (S 1 à S 3 ) montrent que le grenat lié à la formation du skarn, riche en grossulaire, s'est formé lors du dernier épisode de déformation où le grenat était stable, D 3 . La biotite de la génération D 3 dans le gneiss, riche en Cl, montre une intercroissance avec le grenat en veines, et dans les roches du skarn, montre une continuité le long de la gneissosité avec des veines à grenat ± pyroxmangite, hedenbergite ou amphibole, indications d'une période de métasomatose anhydre à aqueuse. Des cartes de répartition d'éléments montrent que l'infiltration s'est propagée à partir de fronts d'altération le long de fissures, indication d'une grande perméabilité le long de S 3 ; ces cartes et les profils de X Grt perpendiculaires aux contacts skarngneiss montrent qu'il y a eu transfert important de masse par infiltration et par dispersion hydrodynamique à divers degrés. D'après la précipitation de cristaux de grenat à zonation oscillatoire en Ca et Mn dans des veines parallèles aux veines remplies de biotite riche en chlore, ainsi que la distribution de telles veines de biotite de part et d'autre du gisement, le tranfert de masse au cours de l'événement D 3 aurait...

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GPT: An excel spreadsheet for thermobarometric calculations in metapelitic rocks

Cited by 67 publications

References 41 publications

Metamorfismo de temperatura ultra-alta de granulitos com safirina de 2,0 Ga do Bloco Itabuna-Salvador-Curaçá, Bahia, Brasil

Metamorfismo de temperatura ultra-alta de granulitos com safirina de 2,0 Ga do Bloco Itabuna-Salvador-Curaçá, Bahia, Brasil

Two Mesoarchaean terranes in the Reguibat shield of NW Mauritania

VEIN AND SKARN FORMATION AT THE CANNINGTON Ag Pb Zn DEPOSIT, NORTHEASTERN AUSTRALIA

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