The Singhbhum craton of eastern India contains an almost continuous depositional record from the Paleoarchean to the Neoproterozoic. Although researchers have examined the Mesoarchean to Neoproterozoic geological history in the last decade, the Paleoarchean sedimentological inventory is poor and the crust-mantle interaction is poorly constrained. Here we present new sedimentological data from the Paleoarchean-early Mesoarchean eastern Iron Ore Group (EIOG) from the Singhbhum craton, India and critically synthesize the earlier published data to constrain the depositional setting of the EIOG succession. Two distinct facies associations characterize the EIOG succession: while the lower facies association is marine and indicates initial shallowing and subsequent deepening of the sea level, the upper facies association is terrestrial (alluvial fan-fluvial) with an unconformable lower contact. The upper facies association formed because of continental emersion at around 3300 Ma. The ultramafic (komatiite)-mafic (minor felsic) volcanic rocks indicate mantle plume activity and crustal contamination. Carbon isotopic analysis of the carbonaceous matter (CM) preserved within the lower facies association reveals that these are syngenetic with the host rock without any evidence of migration of bitumen and modern organic contamination. A peak metamorphic temperature around 450 ± 50 °C is inferred from Raman spectroscopic analysis of the CM. Intensive paleobiological research is of paramount interest to decode the co-evolution of life and environment and the mysteries of early Earth.

印度东部的辛格布姆克拉通包含从古太古代到新元古代几乎连续的沉积记录。尽管研究人员在过去十年中研究了中太古代至新元古代的地质历史，但古太古代沉积学库存很差，壳幔相互作用受到的约束很差。在这里，我们展示了来自印度 Singhbhum 克拉通的古太古代-早中太古代东部铁矿石群 (EIOG) 的新沉积学数据，并批判性地综合了早期发表的数据以限制 EIOG 演替的沉积环境。两种截然不同的相EIOG 演替的特征：虽然下层相组合是海洋的，表明海平面的初始变浅和随后的加深，但上层相组合是陆地（冲积扇-河流），具有不整合的下部接触。3 300 Ma 左右大陆出露形成上相组合。超镁铁质（科马提岩）-镁铁质（小长英质）火山岩表明地幔柱活动和地壳污染。保存在较低相组合内的碳质物质 (CM) 的碳同位素分析表明，这些物质与母岩同生，没有任何沥青迁移和现代有机污染物的证据。从拉曼推断出大约 450 ± 50 °C 的峰值变质温度CM的光谱分析。深入的古生物学研究对于解读生命与环境的共同进化以及早期地球的奥秘至关重要。