Regional UHT metamorphism with widespread, primary CO2-rich cordierite in the Bakhuis Granulite Belt, Surinam: A feldspar thermometry study

Nanne, J. A. M.; Roever, E.W.F. de; Groot, Karlijn de; Davies, Gareth R.; Brouwer, Fraukje M.

doi:10.1016/j.precamres.2020.105894

Cited by 6 publications

(2 citation statements)

References 55 publications

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Section: Ternary Feldspar Geothermometrymentioning

confidence: 99%

“…Ternary feldspar geothermometry is based on the determination of the pre-exsolution feldspar composition by the Hokada (2001) method [39] followed by its plotting on the An-Ab-Or ternary plot with sulvus isotherms. Despite the problematic nature of this approach [51] (Harley 2008), it has been applied to support UHT evidence for many granulite terranes [56,57,61,[65][66][67][68] 5 displays the results of the calculations of one-phase feldspar compositions performed using this technique for the mesoperthic (host/lamellae = 74/26 vol.%) and antiperthitic (host/lamellae = 77/23 vol.%) grains in sample 63. Their re-integrated compositions are Ort 0.62 Ab 0.32 An 0.06 and Ab 0.64 An 0.17 Ort 0.19 , respectively.…”

Section: Ternary Feldspar Geothermometrymentioning

confidence: 99%

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Mineralogical Constraints on the Pressure–Temperature Evolution of Granulites in the Bunger Hills, East Antarctica

Abdrakhmanov,

Gulbin,

Skublov

et al. 2024

Minerals

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Spinel- and orthopyroxene-bearing metapelitic granulites exposed in the Bunger Hills, East Antarctica, have been intensively studied in recent years because they are supposed to record evidence for UHT metamorphism. Detailed petrographic observations, as well as whole rock and mineral chemistry, together with SIMS trace element data on quartz, garnet, and orthopyroxene, are presented for these rocks. Mineral thermobarometry, including Al-in-orthopyroxene, ternary feldspar, Ti-in-quartz, and Fe-Ti oxide solvus, has been used to quantify the UHT conditions. Based on phase equilibrium modeling, a tight clockwise P-T path has been deduced, which involves near-isobaric heating at 6–7 kbar to ~950 °C followed by near-isobaric to slightly up-pressure cooling at 5–6 kbar to ~750 °C. It is concluded that the outlined metamorphic history is characteristic of an extensional crustal regime which is also evidenced by the correlation of prograde and retrograde metamorphism with the extensional and compressional phases of major ductile deformations recognized in the region. In order to constrain the tectonic setting of the granulites, this result is discussed in the context of current views on the Mesoproterozoic evolution of the Albany-Fraser Orogen, the westernmost part of which the Bunger Hills are considered to be.

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Section: Ternary Feldspar Geothermometrymentioning

confidence: 99%

Section: Ternary Feldspar Geothermometrymentioning

confidence: 99%

Mineralogical Constraints on the Pressure–Temperature Evolution of Granulites in the Bunger Hills, East Antarctica

Abdrakhmanov,

Gulbin,

Skublov

et al. 2024

Minerals

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Primary cordierite with > 2.5 wt% CO2 from the UHT Bakhuis Granulite Belt, Surinam: CO2 fluid phase saturation during ultrahigh-temperature metamorphism

Roever¹,

Harley

Huizenga

2023

Contrib Mineral Petrol

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The Paleoproterozoic Bakhuis Granulite Belt (BGB) in Surinam, South America, shows ultrahigh-temperature metamorphism (UHTM) at temperatures of around 1000 °C which, unusually, produced peak-to-near-peak cordierite with sillimanite and, in some cases, Al-rich orthopyroxene on a regional scale. Mg-rich cordierite (Mg/(Mg + Fe) = 0.88) in a sillimanite-bearing metapelitic granulite has a maximum birefringence of second-order blue (ca. 0.020) indicative of a considerable amount of CO2 (> 2 wt%) within its structural channels. SIMS microanalysis confirms the presence of 2.57 ± 0.19 wt% CO2, the highest CO2 concentration found in natural cordierite. This high CO2 content has enabled the stability of cordierite to extend into UHT conditions at high pressures and very low to negligible H2O activity. Based on a modified calibration of the H2O–CO2 incorporation model of Harley et al. (J Metamorph Geol 20:71–86, 2002), this cordierite occupies a stability field that extends from 8.8 ± 0.6 kbar at 750 °C to 11.3 ± 0.65 kbar at 1050 °C. Volatile-saturated cordierite with 2.57 wt% CO2 and negligible H2O (0.04 wt%) indicates fluid-present carbonic conditions with a CO2 activity near 1.0 at peak or near-peak pressures of 10.5–11.3 kbar under UHT temperatures of 950–1050 °C. The measured H2O content of the cordierite in the metapelite is far too low to be consistent with partial melting at 1000–1050 °C, implying either that nearly all of any H2O originally in this cordierite under UHT conditions was lost during post-peak cooling or that the cordierite was formed after migmatization. The high level of CO2 required to ensure fluid saturation of the c. 11 kbar UHT cordierite is proposed to have been derived from an external, possibly mantle, source.

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Rhyacian intermittent large igneous provinces sustained Great Oxidation Event: Evidence from North China craton

Peng

Liu

et al. 2023

Earth-Science Reviews

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Regional UHT metamorphism with widespread, primary CO2-rich cordierite in the Bakhuis Granulite Belt, Surinam: A feldspar thermometry study

Cited by 6 publications

References 55 publications

Mineralogical Constraints on the Pressure–Temperature Evolution of Granulites in the Bunger Hills, East Antarctica

Mineralogical Constraints on the Pressure–Temperature Evolution of Granulites in the Bunger Hills, East Antarctica

Primary cordierite with > 2.5 wt% CO2 from the UHT Bakhuis Granulite Belt, Surinam: CO2 fluid phase saturation during ultrahigh-temperature metamorphism

Rhyacian intermittent large igneous provinces sustained Great Oxidation Event: Evidence from North China craton

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