Early Archean crust in Bastar Craton, Central India—a geochemical and isotopic study

Sarkar, Gautam; Corfú, Fernando; Paul, D. K.; McNaughton, Neal J.; Gupta, S.; Bishui, P. K.

doi:10.1016/0301-9268(93)90097-l

Cited by 181 publications

(60 citation statements)

References 23 publications

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“…1). The Archean crust was consolidated by 2.5 Ga (Sarkar et al 1993;Chadwick et al 2000;Kovach et al 2001), whereas Nd-model ages from different lithologies of the Eastern Ghats Province imply that its crust formed in Proterozoic time . Lithological similarities (Katz 1989), a similar crustal evolution (Mezger and Cosca 1999;Rickers et al 2001), and combined tectonic and petrologic studies at the contact with the Bhandara craton (Gupta et al 2000) strongly suggest that the Eastern Ghats Province and East Antarctica formed one crustal terrane that collided with proto-India during the global Grenvillian orogeny (Mezger and Cosca 1999;Gupta et al 2000).…”

Section: Geological Settingmentioning

confidence: 98%

Emplacement of Proterozoic massif-type anorthosite during regional shortening: evidence from the Bolangir anorthosite complex (Eastern Ghats Province, India)

Dobmeier

2005

Int J Earth Sci (Geol Rundsch)

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A study of the 933±32-Ma-old Bolangir massiftype anorthosite complex (Eastern Ghats Province, India) yielded strong evidence for anorthosite emplacement during regional shortening, and thereby new insights in massif-type anorthosite formation. Several lines of evidence strongly suggest synchronism of plutonism and regional deformation. First, structures in the country rocks, which imply N-S-directed shortening accompanied by E-W extension, are mirrored by a E-W trending post-magmatic foliation and N-S trending shear zones in the anorthosite complex. Near the intrusion, the foliation in the country rocks becomes parallel to the contact and an internal marginal foliation, and foliation triple points occur in the country rocks. Second, synshortening dikes inside and outside the anorthosite complex are filled with pluton-related melts. Third, ferrodiorites, which are considered late-stage differentiates of the anorthositic pluton, concentrate in tectonic voids at the pluton margin. Some of these occurrences have been affected by the last increments of the regional deformation, but others transect the same structures. Ascent mechanism and significance of the adjacent terrane boundary of the Eastern Ghats Belt for ascent and emplacement of the Bolangir anorthosite complex are discussed. The results of this study imply that emplacement of Proterozoic massif-type anorthosite is not restricted to extensional settings.

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Section: Geological Settingmentioning

confidence: 98%

Emplacement of Proterozoic massif-type anorthosite during regional shortening: evidence from the Bolangir anorthosite complex (Eastern Ghats Province, India)

Dobmeier

2005

Int J Earth Sci (Geol Rundsch)

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“…The EGMB is juxtaposed against the Archean cratons, namely the Dharwar, Bhandara-Bastar and Singhbhum Cratons (Figure 1b), which are dominantly comprised of tonalite-trondhjemite gneisses (circa 3.5 Ga) and greenstone belts. Several K-rich granite plutons [circa 2.5 Ga, Sarkar et al, 1993], and dolerite, rhyolite and trachyte dykes [circa 1.4 Ga, Mallikarjuna Rao et al, 1995;Nanda et al, 1998] have intruded the cratons during different geological periods. The cratons are unconformably overlain by the platform sequences of rocks known as the Purana Group [> circa 1.1 Ga; Chatterjee et al, 1995], in several sedimentary basins (Chhatishgarh, Khariar and Cuddapah) surrounding the EGMB front (Figure 1c).…”

Section: Lithologymentioning

confidence: 99%

Timing and dynamics of the juxtaposition of the Eastern Ghats Mobile Belt against the Bhandara Craton, India: A structural and zircon U‐Pb SHRIMP study of the fold‐thrust belt and associated nepheline syenite plutons

2007

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Sensitive High Resolution Ion MicroProbe (SHRIMP) U‐Pb dating of zircon from basement granite gneisses and nepheline syenites of the Sinapalli Nappe, occurring along the northwestern margin of the Eastern Ghats Mobile Belt, indicate high grade regional metamorphism and associated folding accompanying juxtaposition of the nappe with the Bhandara Craton, to have taken place between 617 ± 85 Ma (lower intercept age of a reworked basement unit) and 517 Ma (age of the youngest syenite). This shows, for the first time, that the final juxtaposition of the northwestern parts of the Eastern Ghats Mobile Belt against the Bhandara Craton came about in the late Neoproterozoic and not, as previously thought, during the Mesoproterozoic. The northwestern part of the Eastern Ghats Mobile Belt comprises a fold‐ thrust belt consisting of a stack of northwesterly verging nappes that have been thrust over the Bhandara Craton. The Sinapalli Nappe is the lowermost nappe and rests over a tectonic contact on the Archean granites and gneisses of the craton. The basal décollement is exposed as a two‐km‐wide ductile‐brittle thrust, hosting nepheline syenite plutons that show fabrics consistent with a synkinematic emplacement during thrusting. The Sinapalli Nappe is comprised of a sequence of alternating mafic granulites and quartzofeldspathic gneisses with slivers of basement granites, which are folded in three phases of folding (F1, F2 and F3) and were subjected to granulite facies metamorphism during F1 folding. Thrusting is synkinematic to F2 folding and is responsible for the juxtaposition of the northwestern part of the Eastern Ghats Terrane over the Bhandara Craton during the assembly of parts of eastern Gondwana.

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“…None of the other mafic dykes have been radiometrically dated. However, on the basis of field relationships, the ages of granitoid rocks, and stratigraphic relationship between different rock units (Ramakrishnan, 1990;Sarkar et al, 1993;Srivastava et al, 1996;Singh, 2003b, 2004;Srivastava, 2006a), their approximate emplacement ages may be inferred. It is proposed that the BD1 swarm was emplaced in the Mesoarchaean and BD2 swarm in the Paleoproterozoic (1.88 Ga).…”

Section: Geological Settingmentioning

confidence: 99%

Sr–Nd isotope geochemistry of the early Precambrian sub-alkaline mafic igneous rocks from the southern Bastar craton, Central India

2009

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SummarySr-Nd isotope data are reported for the early Precambrian sub-alkaline mafic igneous rocks of the southern Bastar craton, central India. These mafic rocks are mostly dykes but there are a few volcanic exposures. Field relationships together with the petrological and geochemical characteristics of these mafic dykes divide them into two groups; Meso-Neoarchaean subalkaline mafic dykes (BD1) and Paleoproterozoic (1.88 Ga) sub-alkaline mafic dykes (BD2). The

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Early Archean crust in Bastar Craton, Central India—a geochemical and isotopic study

Cited by 181 publications

References 23 publications

Emplacement of Proterozoic massif-type anorthosite during regional shortening: evidence from the Bolangir anorthosite complex (Eastern Ghats Province, India)

Emplacement of Proterozoic massif-type anorthosite during regional shortening: evidence from the Bolangir anorthosite complex (Eastern Ghats Province, India)

Timing and dynamics of the juxtaposition of the Eastern Ghats Mobile Belt against the Bhandara Craton, India: A structural and zircon U‐Pb SHRIMP study of the fold‐thrust belt and associated nepheline syenite plutons

Sr–Nd isotope geochemistry of the early Precambrian sub-alkaline mafic igneous rocks from the southern Bastar craton, Central India

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