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Sridhar, D. N.
- A New Find of Younger Dolerite Dykes with Continental Flood Basalt Affinity from the Meso-Neoproterozoic Chhattisgarh Basin, Bastar Craton, Central India
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Authors
Affiliations
1 National Geophysical Research Institute, Hyderabad - 560007, IN
2 Pt. Ravishankar Shukla University, Raipur (C. G)., IN
1 National Geophysical Research Institute, Hyderabad - 560007, IN
2 Pt. Ravishankar Shukla University, Raipur (C. G)., IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 69, No 1 (2007), Pagination: 80-84Abstract
Younger and fine-Grained unmetamorphosed dolerite dykes intrude the Raipur Group sediments in the central part of the Meso-Neoproterozoic Chhattisgarh Basin in Central India. Petrologically these dykes consist of unaltered microphenocrysts of intermediate pigeonite (XMg=0.40), augite (XMg=0.595), calcic plagioclase (Xca=O.64), titanomagnetite and ilmenite. These rocks show high Fe2O3T (14.43 to 15.19%), TiO2 (2.75 to 2.87%) and P2O5(0.27 to 0.29%) contents with an unusual Continental Flood Basalt (CFB) affinity. Significantly these dykes show lower K2O content (0.43%). The trace element abundance such as Ba, Sr, Rb, Zr, Nb and trace element ratios Sm/Nd, Ba/Nb, Zr/Nb, Y/Nb, Th/Yb, Ta/Yb and K/Ba in these rocks chemically resemble the least contaminated Deccan Basalts. Chondrite/OIB normalized REE patterns of these rocks also show striking similarities with the Deccan tholeiitic basaltic flows. The available petrological, mineralogical, major, trace and rare earth element data indicate that these within basin basaltic dykes of Raipur are intraplate basalts, which were derived from an enriched mantle source.Keywords
Basaltic Dykes, Chhattisgarh Basin, Geochemistry, Continental Flood Basalts.- New Occurrence of Intrabasinal Ignimbrites and Welded Tuffs from NE Part of the Meso- to Neoproterozoic Chhattisgarh Basin, Bastar Craton: Implications for Petrogenesis
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Authors
Affiliations
1 National Geophysical Research Institute, Hyderabad - 500 007, IN
2 central Ground Water Board, Raipur (CG), IN
3 Pandit Ravi Shankar Shukla University, Raipur (CG), IN
1 National Geophysical Research Institute, Hyderabad - 500 007, IN
2 central Ground Water Board, Raipur (CG), IN
3 Pandit Ravi Shankar Shukla University, Raipur (CG), IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 68, No 4 (2006), Pagination: 589-592Abstract
A new occurrence of Within-Basin pyroclastic flow rocks (welded felsic tuffs and ignimbrites) is reported for the first time from Sukda area in the NE part of the Chhattisgarh basin. The flows are characterized by the presence of microporphyritic textures, feldspars, quartz, glass shards, volcanic rock fragments and magmatic garnet. High concentrations of Na2O (-6.61 wt%), low K2O (0.01 to 1.0 wt%) and high Sr contents (416 ppm) are found in these rocks. REE show a Well-Fractionated trend with high LREE enrichment, sloping HREE patterns and absence of Eu anomalies. Major, trace and REE geochemistry of the Chhattisgarh welded tuffs indicate that they are Na- Rhyolites. The characteristic high Sr/Y and La/YbN, ratios and low HREE contents suggest that the parental magmas of these rocks were produced by extensive partial melting of a mafic source in deeper crustal levels (lower crust) where garnet and or hornblende are residual phases.Keywords
Felsic Tuffs, Na-Rhyolites, Ignimbrites, Chhattisgarh Basin, Chhattisgarh State.- Paleoproterozoic Boninite-Like Rocks in an Intracratonic Setting from Northern Bastar Craton, Central India
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PDF Views:2
Authors
Affiliations
1 National Geophysical Research Institute, Hyderabad-500007, IN
1 National Geophysical Research Institute, Hyderabad-500007, IN