Late Paleoarchean to Neoarchean sedimentation on the Singhbhum Craton, eastern India: a synthesis

Subaerial rise of Earth's first continents took place 3.3-3.2 Ga years ago. This had significant influence on the ocean, at-mosphere, and biosphere. Two important sedimentological consequences of continental emersion were (1) development of terrestrial (alluvial fan-fluvial-aeolian) depositional systems and (2) formation of shallow-marine sedimentary basins near the continental margin. Late Paleoarchean-Neoarchean terrestrial deposits, including development of an extensive paleosol around 3.2 Ga, and Meso-Neoarchean shallow-marine deposits have been reported from the Singhbhum Craton, eastern India from several localities. However, lateral and vertical changes in sedimentary facies associations and stratigraphic correlation between these terrestrial to shallow-marine sedimentary deposits have not yet been investigated. In this paper, we have re-viewed the sedimentological characteristics of Late Paleoarchean to Neoarchean (3.2-2.8 Ga) stratigraphic successions of the Singhbhum Craton and have discussed sea level change and mode of stratigraphic sequence building. Our analysis shows that Singhbhum granitoid complex was emplaced around 3.3 Ga in an intracontinental setting, resulting in high continental freeboard conditions that triggered terrestrial (alluvial fan-braided fluvial) sedimentation (Dhosrapahar Formation). Continen-tal sedimentation continued until ca. 3.0 Ga. In the eastern (Simlipal Group), western (Birtola Formation), and southwestern (the Mankarchua, Mahagiri, and Keonjhar formations) parts, shallow-marine sedimentation occurred after 3.0 Ga as a result of transgression. However, in the northern part (Dhanjori Formation), continental sedimentation prevailed throughout the Archean. These Late Paleoarchean to Neoarchean terrestrial and near-coastal successions of Singhbhum Craton should be the prime targets for intense geobiological research.

Automated summary

The rise of the first continents on Earth occurred 3.3-3.2 billion years ago, which had a significant impact on the ocean, atmosphere, and biosphere. This led to the development of terrestrial depositional systems and the formation of shallow-marine sedimentary basins. In the Singhbhum Craton of eastern India, Late Paleoarchean-Neoarchean terrestrial and shallow-marine deposits have been found, but their sedimentary facies associations and stratigraphic correlation have not been investigated. This study examines the sedimentological characteristics of these deposits and discusses sea level change and sequence building. It is suggested that these deposits should be the focus of intense geobiological research.