New U-Pb zircon ages from Paleo-Mesoarchean TTG gneisses of the Singhbhum Craton, Eastern India

Geochemical and Sm–Nd isotopic characteristics of the Late Archaean-Palaeoproterozoic Dhanjori and Chaibasa metasedimentary rocks, Singhbhum craton, E. India: Implications for provenance, and contemporary basin tectonics

“…Formation S12 S13 S14 S15 S16 S17 S18 S19 S20 S21 S22 S23 S25 S24 S30 S29 S28 S27 S32 S33 S26 S31 S11 mantle. In the case of the two samples this must have been before and after 2.5 Ga, e.g., some of the material in the Dhanjori samples was derived from the mantle later than 2.5 Ga, and consequently deposition of this mixed material must have occurred also later than 2.5 Ga. As a reference isotopic framework for data interpretation we can assume a basement source with a Nd model age of 3.6 Ga (Table 3, tonalite sample S34), which is broadly consistent with the age of the basement in this part of the Singhbhum craton (Acharyya et al, 2010a;Hofmann and Mazumder, 2014). At 2.5 Ga, the assumed onset of deposition of Dhanjori sediments, the basement source had evolved to ε Nd of −11, and at 2.2 Ga, the assumed deposition of Chaibasa to −15 (Table 3).…”

“…Typically, sedimentary rocks contain recycled older crustal material, in this case from the ca. 3.3 Ga basement (Singhbhum granitoid phase III or still older Older Metamorphic Tonalitic gneiss, see Saha, 1994, Acharyya et al, 2010a, Mazumder et al, 2012aand Hofmann and Mazumder, 2014 for details) so that their model age represents an average value for the times when material was derived from the Table 2 Major-and trace element concentrations of Palaeoproterozoic Dhanjori and Chaibasa Formations, Singhbhum craton, eastern India. Formation S12 S13 S14 S15 S16 S17 S18 S19 S20 S21 S22 S23 S25 S24 S30 S29 S28 S27 S32 S33 S26 S31 S11 mantle.…”

Neoarchean–Paleoproterozoic stratigraphy of the Dhanjori basin, Singhbhum Craton, Eastern India: And recording of a few U–Pb zircon dates from its basal part

“…Thus the age of major and younger component of OMTG (3405 ± 26 Ma, Pb-Pb isochron age on WR, Ghosh et al, 1996;ca. 3440 Ma, Pb-Pb age on zircon, Mishra et al, 1999; 3448 ± 19 Ma U-Pb age on zircon, Acharyya et al, 2010) match with the age of the older component of SBG-A (3442 ± 26 Ma, Pb-Pb on WR isochron age, Ghosh et al, 1996) recorded from different parts of the Singhbhum Craton. The other new zircon age 3527 ± 17 Ma, from the same Kalikapur OMTG body possibly corresponds to an older intrusive or inherited from a xenocryst population (Acharyya et al, 2010).…”

“…1a) range in age from 3660 to 3330 Ma (Pb-Pb on WR, Moorbath et al, 1986; Sm-Nd on WR, Sharma et al, 1994; Pb-Pb on zircon, Goswami et al, 1995; Pb-Pb on WR, Ghosh et al, 1996; Pb-Pb on zircon, Mishra et al, 1999; U-Pb SMRIMP on zircon, Nelson et al, 2007). In course of our recent work on the least studied northern area of the craton, zircon recovered from TTG type gneisses (OMTG; Kalikapur body in Saha, 1994) has yielded new U-Pb ages of 3448 ± 19 Ma and 3527 ± 17 Ma (Acharyya et al, 2010).…”

“…Acid volcanics from the southern IOG belt have been dated at 3507 ± 2.3 Ma (U-Pb on zircon by SHRIMP; Mukhopdhyay et al, 2008), which is older than the two SBG phases, as well as, the major and younger component of the OMTG. Therefore, OMG enclaves, considered as the oldest supracrustal rocks in the region might be derived from IOG rocks (Acharyya et al, 2010). The Tamperkola and the Mayurbhanj Granite plutons occurring close to the western and eastern margins of the Singhbhum Craton provide clear evidence of Neoarchean (3.0-2.8 Ga) magmatic activity Mishra et al, 1999;Bandyopadhyay et al, 2001).…”