Major turbidity flows in the Western Indus Fan between 290 and 360 kyr

Abstract

Calcium carbonate (CaCO sub(3)), aluminium (Al), titanium (Ti), and terrigenous matter analyses were carried on the Ocean Drilling Programme Site 720A from the Indus Fan in the Arabian Sea. CaCO3, Al, Ti and terrigenous matter values range from 4.5 to 74.4%, 1.4 to 7.8%, 0.03 to 0.4% and 5.5 to 66.7%, respectively. High CaCO sub(3) (40-60%) in association with low values of Al, Ti and terrigenous matter from 0 to 290 kyr (0 to 18 mbsf) and low CaCO sub(3) (< 10%) with high values of Al, Ti and terrigenous matter suggest that CaCO sub(3) fluctuations at this site were controlled by terrigenous dilution. Low Al, Ti and terrigenous matter percentages from 0 to 290 kyr and strikingly high values from 290 to 360 kyr reveal that the supply of terrigenous matter to the Indus Fan was significantly higher during 290 to 360 kyr (18 to 28 mbsf depth) due to massive turbidity flows triggered by slumping.