Similarities in the mineralogical and geochemical attributes of detrital clays of Maastrichtian Lameta Beds and weathered Deccan basalt, Central India

Mineralo-chemical attributes of the Maastrichtian (Late Cretaceous) Lameta sediments, intimately associated with the Deccan Traps in Central India, provide insight into the initiation of Deccan volcanism. X-ray diffraction studies on the detrital clays of the Lametas and weathered Deccan basalt show identical mineral assemblages with the dominance of smectite and subordinate kaolinite, illite. IR spectra are also indicative of their common mineralogical attributes. Structural formulae of the smectites in Lameta exhibit high octahedral Mg and Fe. The immobile trace-element concentrations in Lameta clays resemble those in weathered Deccan basalt. REE plots of the Lametas are subparellel with that of weathered Deccan basalt and show negative Ce anomalies documented in basalt weathering.These findings suggest that smectite-rich clays of the Lametas are derivatives of the Deccan basalt, implying early activities of Deccan volcanism either during or just prior to the Maastrichtian Lameta sedimentation.