U–Cr-rich high Mg-Al granulites from Karimnagar Granulite Belt, India: implications for Neoarchean-Paleoproterozoic events in southern India

Sarbajna, Chanchal; Bose, Sankar; Rajagopalan, V.; Das, Kaushik; Som, Anjan; Paul, A. K.; Shivkumar, K.; Umamaheswar, K.; Chaki, Anjan

doi:10.1007/s00710-012-0242-6

Cited by 12 publications

(2 citation statements)

References 40 publications

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“…However, the presence of sapphirine in a rock does not immediately indicate that the rockdand terranednecessarily records temperatures in excess of 900 C. For example, Kruckenberg and Whitney (2011) and Goergen and Whitney (2012b) reported symplectic sapphirine in quartzabsent MgeAl-rich rocks that attained temperatures of approximately 750 C. In addition, there are a number of occurrences of sap phirineespinelebiotite-bearing rocks (AE corundum AE ortho pyroxene AE plagioclase AE sillimanite AE garnet AE chlorite, and all quartz-absent) that appear to record temperatures less than 900 C (e.g. Oliver and Jones, 1965;Kelsey et al, 2005;Prakash and Sharma, 2008;Raith et al, 2008;Sharma and Prakash, 2008;Nasipuri et al, 2009;Prakash et al, 2013;Sarbajna et al, 2013). Ferric iron is known to expand the stability of sapphirine to lower temperatures (e.g.…”

Section: Nomentioning

confidence: 94%

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

Kelsey

Hand

2015

Geoscience Frontiers

377

285

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a b s t r a c tUltrahigh temperature (UHT) metamorphism is the most thermally extreme form of regional crustal metamorphism, with temperatures exceeding 900 C. UHT crustal metamorphism is recognised in more than 50 localities globally in the metamorphic rock record and is accepted as 'normal' in the spectrum of regional crustal processes. UHT metamorphism is typically identified on the basis of diagnostic mineral assemblages such as sapphirine þ quartz, orthopyroxene þ sillimanite AE quartz and osumilite in MgeAlrich rock compositions, now usually coupled with pseudosection-based thermobarometry using internally-consistent thermodynamic data sets and/or Al-in-Orthopyroxene and ternary feldspar thermobarometry. Significant progress in the understanding of regional UHT metamorphism in recent years includes: (1) development of a ferric iron activityecomposition thermodynamic model for sapphirine, allowing phase diagram calculations for oxidised rock compositions; (2) quantification of UHT conditions via trace element thermometry, with Zr-in-rutile more commonly recording higher temperatures than Ti-in-zircon. Rutile is likely to be stable at peak UHT conditions whereas zircon may only grow as UHT rocks are cooling. In addition, the extent to which Zr diffuses out of rutile is controlled by chemical communication with zircon; (3) more fully recognising and utilising temperature-dependent thermal properties of the crust, and the possible range of heat sources causing metamorphism in geodynamic modelling studies; (4) recognising that crust partially melted either in a previous event or earlier in a long-duration event has greater capacity than fertile, unmelted crust to achieve UHT conditions due to the heat energy consumed by partial melting reactions; (5) more strongly linking UePb geochronological data from zircon and monazite to PeT points or path segments through using Y þ REE partitioning between accessory and major phases, as well as phase diagrams incorporating Zr and REE; and (6) improved insight into the settings and factors responsible for UHT metamorphism via geodynamic forward models. These models suggest that regional UHT metamorphism is, principally, geodynamically related to subduction, coupled with elevated crustal radiogenic heat generation rates.Ó 2014, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

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Section: Nomentioning

confidence: 94%

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

Kelsey

Hand

2015

Geoscience Frontiers

377

285

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“…Sapphirine occurring in a silica-saturated but oxidizing system recording non-UHT conditions sets a precedent, although numbers of Spr-Spl-Bt-bearing, but Qz-absent rocks, have been obtained temperatures less than 900 • C (e.g. Nasipuri et al, 2009;Prakash et al, 2013;Raith et al, 2008;Sharma and Prakash, 2008;Sarbajna et al, 2013), and even down to 750 • C (Kruckenberg and Whitney, 2011), as reviewed in Kelsey and Hand (2015).…”

Section: Peak P-t Conditions and P-t Pathmentioning

confidence: 98%

Short-lived high-temperature prograde and retrograde metamorphism in Shaerqin sapphirine-bearing metapelites from the Daqingshan terrane, North China Craton

Jiao

Guo

Wang

et al. 2015

Precambrian Research

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A New Occurrence of Sapphirine-Spinel-Corundum-bearing Granulite from NE of Jagtiyal, Eastern Dharwar Craton, Andhra Pradesh

Prakash

Singh

Hokada

2013

Journal of the Geological Society of India

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We report a new occurrence of sapphirine-spinel-corundum bearing granulites enclosed in granitic gneisses near Jagtiyal in the Eastern Dharwar Craton (EDC). These granulites are very important in deciphering the prehistory of the thermal peak of metamorphism due to the presence of refractory phases. The appearance of sapphirine is related to the following reactions: (a) Spl1 + Crd1 = Spr1 (2:2:1) (b) Phl (in Bt1) + Crn1 = East (in Bt2) + Spr2 (7:9:3) + Crd2 (c) Bt2 + Crd1 +Crn1 = Spr2 (7:9:3) + Kfs + H2O (d) Crd1 + Spl1 + Crn1 = Spr2 (7:9:3). The P–T evolution of these sapphirine granulites has been constrained through the use of THERMOCALC program. Temperature of formation of sapphirine-spinel assemblages is high, around 800 °C, and pressure ranges from 5-7 kbars, suggesting that sapphirine formation took place during decompression stage.

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U–Cr-rich high Mg-Al granulites from Karimnagar Granulite Belt, India: implications for Neoarchean-Paleoproterozoic events in southern India

Cited by 12 publications

References 40 publications

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

On ultrahigh temperature crustal metamorphism: Phase equilibria, trace element thermometry, bulk composition, heat sources, timescales and tectonic settings

Short-lived high-temperature prograde and retrograde metamorphism in Shaerqin sapphirine-bearing metapelites from the Daqingshan terrane, North China Craton

A New Occurrence of Sapphirine-Spinel-Corundum-bearing Granulite from NE of Jagtiyal, Eastern Dharwar Craton, Andhra Pradesh

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