190 likes | 209 Views
Iron Ore Group, Eastern Indian Craton Asish Basu University of Rochester New York 14627.
E N D
Iron Ore Group, Eastern Indian Craton Asish Basu University of Rochester New York 14627
Geological map of the Eastern Indian Craton in the Singhbhum-Orissa region of the Indian continent (see inset) modified after [13] and [17]. The current study area is to the north of Bonai Granite. The sandstones of this study are from the Darjing group, west of Singhbhum Granite. Samples analyzed are from a sedimentary succession shown by the crossed box. Abbreviations: OMG, Older Metamorphic Group; OMTG, Older Metamorphic Tonatile Gneisses. The ages of the relevant rocks are: Tamperkola Granite, ~2.8 Ga; Bonai Granite, ~3.2 Ga; Singhbhum Granite Complex, ~ 3.1 Ga; OMTG, ~3.3 Ga; OMG, ~ 3.3Ga. See text for geologic-lithologic details.
Nb/Ta ratios vs. Zr/Sm ratios of the analyzed sandstones compared to the Archean tonalite-trondhjemite gneisses (TTGs) and present day continental crust and adakites. Also shown are modern day MORBs, OIBs, and island arc basalts (IABs)[38]. The sandstones of this study are identical to Archean TTGs, indicating that the protoliths of the sandstones formed in similar petrotectonic environment.
Th/U = 1.7 to 2.5 0.5 mm
Age = 3.4Ga eNd(T) = -4.9 eNd(0) = -38.2
eNd(3.4Ga) = +2.8 to +6.8 eNd(3.4Ga) = +0.4 to +3.8 eNd(3.4Ga) = +0.8 to +6.0
Geological map of the Eastern Indian Craton in the Singhbhum-Orissa region of the Indian continent (see inset) modified after [13] and [17]. The current study area is to the north of Bonai Granite. The sandstones of this study are from the Darjing group, west of Singhbhum Granite. Samples analyzed are from a sedimentary succession shown by the crossed box. Abbreviations: OMG, Older Metamorphic Group; OMTG, Older Metamorphic Tonatile Gneisses. The ages of the relevant rocks are: Tamperkola Granite, ~2.8 Ga; Bonai Granite, ~3.2 Ga; Singhbhum Granite Complex, ~ 3.1 Ga; OMTG, ~3.3 Ga; OMG, ~ 3.3Ga. See text for geologic-lithologic details.