Geochemistry of sandstones from the Imphal Valley, Indo-Myanmar

Spheroidal weathered siliciclastic rocks of the Imphal Valley, Indo-Myanmar Ranges were studied to determine paleoclimate, paleoweathering and mineral alteration based on the geochemical and mineralogical compositions. The Chemical Index of Alteration (CIA) suggests low-intermediate chemical weathering. Plagioclase Index of Alteration (PIA) value indicates incipient plagioclase alteration. Mineralogical Index of Alteration (MIA) reveals incipient to intermediate mineralogical alteration and the A-CN-K ternary plot of the studied samples suggests a low rate of alteration. The results suggest semi-arid climate, which ranges from warm-arid to warm cool conditions. Geochemistry and mineralogy indicate felsic, mafic and ultramafic compositions for the siliciclastic rocks.