S B Dwivedi
Articles written in Journal of Earth System Science
Volume 105 Issue 4 December 1996 pp 365-377
The non-ideal regular Mg-Fe binary in cordierite has been derived through multivariate linear regression of the expression
Volume 122 Issue 3 June 2013 pp 743-757
The metamorphic evolution of the contact aureole around the Late Paleoproterozoic Jhirgadandi pluton in the eastern part of Parsoi Formation of Mahakoshal terrain, central India represents three distinct metamorphic zones, characterized by definite mineral assemblages. The contact-metamorphic event produced the peak-metamorphic mineral assemblages Bt + Qtz + Alb + Sil ± Cd ± Grt ± Mus ± Kfs in the metapelites of inner aureole, Bt + Qtz + And + Mus + Kfs + Plag ± Cd ± Chl in middle aureole and Chl + Mus + Bt ± And + Alb + Qtz ± Ep + Mt ± tourmaline in the outer aureole. The estimated P–T conditions based on detailed geothermobarometric calculations in the thermal metamorphosed rocks are 690°C/3.4 kbar, 580 ± 15°C and 487 ± 30°C in inner aureole, middle aureole and outer aureole, respectively. The variation in metamorphic condition suggests that the shallow crustal level emplacement of Jhirgadandi pluton is responsible for the overprinting of contact metamorphic assemblages ($M_2$) in the low grade metapelites (regional metamorphism $M_1$) of Mahakoshal Group.
Volume 124 Issue 1 February 2015 pp 197-211
The Bundelkhand Gneissic Complex (BnGC) in the central part of the Bundelkhand massif preserves a supracrustal unit which includes pelitic (garnet–cordierite–sillimanite gneiss, garnet–sillimanite gneiss, biotite gneiss and garnet–biotite gneiss) and mafic (hornblende–biotite gneiss and garnetiferous amphibolite) rocks. Granulite facies metamorphism of the complex initiated with breaking down of biotite to produce garnet and cordierite in the pelitic gneisses. Geothermobarometric calculations indicate metamorphic conditions of 720°C/6.2 kbar, followed by a retrograde (687°C/4.9 kbar) to very late retro-grade stages of metamorphism (579°C/4.4 kbar) which is supported by the formation of late cordierite around garnet. The P–T conditions and textural relations of the garnet–cordierite-bearing gneiss suggest a retrograde cooling path of metamorphism.
Volume 130, 2021
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