Estimates of the average Pacific deep-sea clay accumulation rate from material balance calculations

Abstract

In the absence of a large number of radiocarbon dated cores from the Pacific Ocean for comparison with the Atlantic Ocean, two methods of determining the average deep-sea clay accumulation rate in the Pacific relative to the Atlantic using material balance calculations are discussed. Using the average deep-sea clay accumulation rate in the Atlantic Ocean of 1.1 to 1.2 g/cm 2 1000 year the “trace element veil” concept of Wedepohl and others, requires a minimum ratio of Atlantic clay rate to Pacific clay rate of 12 to be consistent with the data of a Carribean Core A179-4. This model, however, is rejected because of the inhomogenous distribution of the critical trace elements in the oceans. The calcium carbonate balance sheet requires that of the 122 × 10 16 g equivalent CaCO 3 brought to the sea by streams, 77 × 10 16 g CaCO 3 is deposited in the Atlantic Ocean. Assuming the average calcium carbonate concentrations and the average clay accumulation rates per unit area of the Indian Ocean and the Pacific Ocean are the same, the deep-sea clay accumulation rate for both oceans is 0.47 g/cm 2 1000 y. It is argued that the average clay accumulation rate is actually probably smaller in the Pacific Ocean relative to the Indian Ocean and the ratio of the Atlantic clay rate to the Pacific clay rate is greater than 2.6.