Sedimentation history of the Palaeoproterozoic Dhanjori Formation, Singhbhum, eastern India

Abstract

The Palaeoproterozoic Dhanjori Formation, eastern India is a terrestrial (dominantly fluvial) volcano-sedimentary succession. Basal conglomerate, coarse-grained sandstone, and shale rests directly on the granite basement and represents the distal fringe of an alluvial fan complex. Sieve, sheet flood, mass flow and alluvial channel and overbank deposits comprise the fan segment. The rest of the formation is entirely constituted by fining upward fluvial cycles. An event of basin tilting and volcanic eruption intervened and resulted a second phase of Dhanjori sedimentation, although the general fluvial depositional framework remained unaltered. The two members of the Dhanjori Formation display different paleocurrent trends related to fluvial response to basin tilting. In the lower member spatial variability in paleocurrent directions occurs as a consequence of fan development. Unlike the first phase, the second phase of fluvial deposition incorporates profuse volcanics and accompanying volcaniclastic deposits. These volcanic and volcaniclastic rocks might have locally blocked the river courses resulting in short-lived lacustrine deposition. Composition of the volcanics varies upward from ultramafic to mafic. The Dhanjori volcanism took place in an intracontinental rift setting as is evident from the interbedded terrestrial deposits. Interbedded volcanic and volcaniclastic rocks in different stratigraphic levels suggest episodic volcanic eruption. A semiarid paleoclimate is proposed and is consistent with development of an alluvial fan comprised of coarse clastic deposits.

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

“…As the detailed sedimentary facies analysis of the Dhanjori (Mazumder and Sarkar, 2004;Mazumder, 2005) and Chaibasa (Bhattacharya, 1991;Bose et al, 1997;Mazumder, 2005;Mallik et al, 2012) Formations have been done earlier, we will summarize the salient sedimentary facies characteristics and inferred depositional environments relevant to the sedimentary geochemistry for the sake of brevity. Interested reader may consult Mazumder et al (2012b) for an overview of Palaeoproterozoic sedimentation in Singhbhum craton.…”

“…In addition, coarser upper Dhanjori sandstones contain siltstone and shale fragments albeit in low frequency (cf. Mazumder and Sarkar, 2004;Mazumder, 2005). Sandstone compositions vary from arkose to feldspathic arenite to lithic arenite/wacke, depending on relative proportion and dominant species of feldspar (cf.…”

“…Sandstone compositions vary from arkose to feldspathic arenite to lithic arenite/wacke, depending on relative proportion and dominant species of feldspar (cf. Pettijohn, 1975;Bose, 1994;Mazumder and Sarkar, 2004). Mazumder and Sarkar (2004) for details.…”

“…The Dhanjori Formation represents the lower part of the Late-Archaean to Palaeoproterozoic volcano-sedimentary succession and unconformably overlies the Archaean nucleus. It is entirely siliciclastic and incorporates mostly mafic -and minor felsic volcanics and volcaniclastic rocks (Gupta and Basu, 2000;Mazumder and Sarkar, 2004;Mazumder, 2005). The Dhanjori Formation is conformably overlain by the thicker, and entirely siliciclastic Chaibasa Formation (Mazumder, 2005;Mazumder et al, 2012aMazumder et al, ,b, 2014.…”

“…Although earlier researchers studied the sedimentary facies, mode of sedimentary sequence building and stratigraphic relationship between the Dhanjori (Mazumder, 2002;Mazumder and Sarkar, 2004;Mazumder, 2005;Bhattacharya and Mahapatra, 2008;) and Chaibasa Formation (Bose et al, 1997;Bhattacharya and Bandyopadhyay, 1998;Mazumder, 2002Mazumder, , 2004Mazumder, , 2005Mallik et al, 2012), issues related to the sediment geochemistry, provenance and tectonic milieu of deposition of these two formations are hitherto unknown (cf. Mazumder et al, 2012a).…”