Geochemical and Sedimentological Signatures of Ariyankuppam and Chunnambar Estuarine Sediments, Pondicherry, India: Implications on Weathering and Provenance

Abstract

Thirty surface sediment samples collected from Ariyankuppam (N =12) and Chunnambar estuaries (N = 18) located along the coast of Pondicherry, India, are analyzed to understand the nature of weathering and provenance. The granulometric study reveals that sediments are poorly sorted, positively skewed and platykurtic to leptokurtic in nature. The abundance and inverse relationship of SiO2 with other major oxides signify the detention of silica within quartz. The Index of Chemical Variability (ICV) suggests that sediments are compositionally immature and are derived from less weathered source rock. The weathering indices such as the Chemical Index of Alteration (CIA); Chemical Index of Weathering (CIW); Plagioclase Index of Alteration (PIA), and A-CN-K diagram also suggest less intense weathering of parent rocks. The major and trace element ratios viz. Al₂O₃/TiO₂, TiO₂/Zr, Cr/V and Y/Ni and discrimination diagrams indicate that estuarine sediment is derived from felsic and intermediate provenance.