SURFICIAL CLAY MINERAL DISTRIBUTION ON THE SOUTHWESTERN CONTINENTAL-MARGIN OF INDIA - EVIDENCE OF INPUT FROM THE BAY-OF-BENGAL

Analyses of spatial distribution of clay minerals, sediment texture, a nd > 63 mu m fractions of the grab samples from the SW continental mar gin of India exhibit: (i) higher contents of illite and chlorite on th e lower slope and (ii) a well-defined no-clay zone on the entire shelf . Kaolinite and smectite are also present in significant quantities on the slope with traces of gibbsite and palygorskite in some samples. T he high contents of illite and chlorite (clay minerals which are not a bundant in the soils and estuarine sediments of this region) in the so uthern region of the study area are evidence for sediment contribution from the Bay of Bengal waters (BBW), which enter this region after th e SW monsoon. Distribution trends of kaolinite, smectite, gibbsite, an d laterite granules on the slope are suggestive of contribution from c hemically weathered soils of Peninsular India.