Fluids in metamorphic rocks

Touret, Jacques

doi:10.1016/s0024-4937(00)00036-0

Cited by 232 publications

(121 citation statements)

References 19 publications

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“…Inclusions seem to have formed during a single fluid-rock interaction event; their distribution as 240 small clusters and along trails, which never reach grain boundary edges, is indicative for early 241 trapping (cf., Touret, 2001). Absence of inclusions in (olivine and orthopyroxene) neoblasts, in 242 pargasite, and in most clinopyroxene grains, indicate formation just prior to or contemporaneously 243 with recrystallization of peridotites.…”

Section: Composition Of Peridotites 206 207mentioning

confidence: 99%

Chlorine-rich metasomatic H2O–CO2 fluids in amphibole-bearing peridotites from Injibara (Lake Tana region, Ethiopian plateau): Nature and evolution of volatiles in the mantle of a region of continental flood basalts

Frezzotti

Ferrando

Peccerillo

et al. 2010

Geochimica et Cosmochimica Acta

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Section: Composition Of Peridotites 206 207mentioning

confidence: 99%

Chlorine-rich metasomatic H2O–CO2 fluids in amphibole-bearing peridotites from Injibara (Lake Tana region, Ethiopian plateau): Nature and evolution of volatiles in the mantle of a region of continental flood basalts

Frezzotti

Ferrando

Peccerillo

et al. 2010

Geochimica et Cosmochimica Acta

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“…The common occurrence of CO 2 rich inclusions in rocks that were generated in the deeper parts of the crust serves as a strong evidence for this model. However, the mechanism and timing of entrapment of such fluids have been topics of debate (Touret, 2001;Santosh, 1992;2003 and references therein).…”

Section: Introductionmentioning

confidence: 99%

"Ultrahigh density" carbonic fluids in ultrahigh-temperature crustal metamorphism

Santosh

Tsunogae

Yoshikura

2004

Journal of Mineralogical and Petrological Sciences

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Ultrahigh temperature (UHT) granulites in Tonagh Island, Napier Complex, East Antarctica record peak metamorphic pressure temperature (P T) conditions of up to 9 kbar and 1100°C. Sapphirine, garnet, orthopyroxene and quartz in these rocks contain very high density fluid inclusions with melting temperatures close to that of pure CO 2 (−56.6°C) and homogenization temperatures down to −34.9°C translating into high CO 2 densities (up to 1.07 g/cm 3 ). The UHT granulites of Vizianagram in Eastern Ghats Belt, India which were subjected to extreme crustal metamorphism at >1000°C and 8 9 kbar also carry very high density (up to 1.15 g/cm 3 ) pure CO 2 inclusions in quartz adjacent to spinel rimmed by various coronas of sillimanite, orthopyroxene and garnet. Garnets in a granulite facies rock from Salem in southern India that equilibrated at peak P T conditions of 740 800°C and 9 11 kbar carry the highest density (1.17 g/cm 3 ) pure CO 2 yet reported from continental crust. This rock also contains very high density CO 2 inclusions in plagioclase and quartz. High density (0.998 g/cm 3 ) pure CO 2 rich fluid inclusions also occur abundantly within garnets from a mafic granulite in Ampitiya, central Highland Complex, Sri Lanka. The peak P T conditions of metamorphism of the mafic granulite are around 10.6 kbar and 985°C with subsequent rapid isothermal decompression along a clock wise path down to 5.5 kbar. In most of the cases above, the representative isochores for the CO 2 inclusions either penetrate through or pass very close to the P T windows defined from mineral phase equilibria indicating that the fluid inclusions were trapped at the time of peak or near post peak metamorphism. We thus recognize a group of "ultrahigh density" (UHD) CO 2 rich fluids that characterize UHT rocks and other granulites formed under extreme crustal metamorphism. These fluids contrast sharply with the lower density (generally <1.0 g/cm 3 ) CO 2 inclusions commonly reported from normal granulite facies rocks in various terrains. The presence of "synmetamorphic" UHD CO 2 within various minerals is consistent with the low water activities predicted by the mineral assemblages in these rocks. Although the source of the CO 2 is equivocal, mantle derived mafic magmas could have provided the heat and volatiles required for crustal metamorphism at extreme conditions displayed by these rocks.

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“…Doubly polished thin wafers of 120 150 μm thickness were prepared from the samples. The inclusion occurrence, distribution, shape, size, and phase category were carefully studied using a microscope at various magnifications following the techniques outlined by Roedder (1984), Touret (2001), and van den Kerkhof and Hein (2001). The results are summarized in Table 3.…”

Section: Fluid Inclusions Petrographymentioning

confidence: 99%

“…Detailed petrographic observations and microthermometric measurements of fluid inclusions can aid this process. Such results have been widely used to infer the P T X conditions and exhumation paths for high grade metamorphic rocks (e.g., Touret and Hansteen, 1988;Santosh et al, 1991;Touret, 2001).…”

Section: Introductionmentioning

confidence: 99%

Fluid inclusions study of Abukuma metamorphic rocks from the Hanazono district, northeast Japan

Ohyama

Tsunogae

2007

Journal of Mineralogical and Petrological Sciences

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A systematic fluid inclusion study on pelitic and granitic gneisses of the Cretaceous Abukuma metamorphic rocks, exposed in the Hanazono district, northeast Japan, identified three categories of fluid inclusions: primary aqueous inclusions in porphyroblastic garnet, primary to pseudosecondary carbonic inclusions in quartz, and secondary aqueous inclusions in quartz. The primary aqueous inclusions in garnet exhibit melting and homogenization temperatures of −2.5 to −0.3 °C and +168.2 to +360.0 °C, respectively. The dominant primary to pseudosecondary fluid inclusions in undeformed quartz display melting temperatures of −64.2 to −56.6 °C, indicating a CO 2 rich composition with additional CH 4 and/or N 2 . The carbonic inclusions can be divided into high density (1.121 1.153 g/cm 3 ) and medium density (0.683 1.111 g/cm 3 ) types. The fluid densities of the latter inclusions, when translated into isochores, indicate entrapment of CO 2 at the peak P T conditions experienced by rocks in the study area (2.8 5.2 kbar at 770 850 °C). In contrast, the isochores of high density category in quartz and aqueous inclusions in garnet do not intersect the expected P T trajectory, yet are consistent with the prograde high pressure condition of the Abukuma metamorphic rocks in the Takanuki district (8 10 kbar at 700 750 °C). Isochores calculated for carbonic inclusions in granitic gneiss intersect the P T path at 2 3 kbar at 650 °C, suggesting that the fluids were captured during the retrograde stage. It is inferred that H 2 O was the dominant fluid species during the prograde stage, while CO 2 was more abundant during the peak to retrograde stages of the Abukuma metamorphic belt. The prograde H 2 O bearing fluid was probably derived from the break down of hydrous minerals. Although the origin of carbonic fluid is not known, the presence of CO 2 rich fluid during peak metamorphism probably lowers the H 2 O activity in the rocks. The isochores computed for secondary aqueous inclusions in quartz give very low P T conditions (300 °C and 1.7 3.5 kbar), suggesting that the fluids are of retrograde origin.

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Fluids in metamorphic rocks

Cited by 232 publications

References 19 publications

Chlorine-rich metasomatic H2O–CO2 fluids in amphibole-bearing peridotites from Injibara (Lake Tana region, Ethiopian plateau): Nature and evolution of volatiles in the mantle of a region of continental flood basalts

Chlorine-rich metasomatic H2O–CO2 fluids in amphibole-bearing peridotites from Injibara (Lake Tana region, Ethiopian plateau): Nature and evolution of volatiles in the mantle of a region of continental flood basalts

"Ultrahigh density" carbonic fluids in ultrahigh-temperature crustal metamorphism

Fluid inclusions study of Abukuma metamorphic rocks from the Hanazono district, northeast Japan

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