Physico-Chemical Characteristics of the Barremian-Aptian Siliciclastic Rocks in the Pondicherry Embryonic Rift Sub-basin, India

Source-signature imbibed within geochemistry and detrital mineralogy gets blurred when correlated with physical characteristics in the Barremian-Aptian siliciclastic-fill of the Pondicherry Sub-basin, India. Six alluvial conglomerate-shale facies associations linked with paleocurrent patterns present a facsimile of basin-margin scree/alluvial fans transiting into a low-sinuosity axial river system, in turn passing into a distal floodplain traversed by high-sinuosity channel branches. The QFL-plot for the sandstones indicates cratonic source gaining relative maturity toward the distal depositional setting. Geochemical data clearly document variable degrees of mixing of felsic and mafic components, and source-shifting in concert with rifting. Weathering had been moderate with an annual temperature around 12°C and rainfall 844–1060 mm, although geophysical reconstructions suggest high paleolatitude. Intrabasinal sediment transport and diagenesis, nonetheless, left a noteworthy overprint.