Barium, equatorial high productivity, and the northward wandering of the Indian continent

High concentrations of biologically precipitated barite characterize the deep‐sea sediments underlying the equatorial high‐productivity belt of the Indian Ocean. By studying the barium distribution in five Deep Sea Drilling Project cores (213–217), drilled in the eastern Indian Ocean north of and below the present high‐productivity zone, it is possible to determine the times when the different coring sites passed beneath the zone. From this information, net northward spreading rates of the Indian plate can be deduced. The results suggest that northward movement was very rapid during the early and middle Paleogene, slow during the mid‐Cenozoic, and then rapid again from the Late Miocene onwards. The Late Miocene revitalization of active seafloor spreading south of the Indian continent coincides with the main phase of the Himalayan uplift. Supplemental tables are availablewith entire article on microfiche. Orderfrom American Geophysical Union, 2000Florida Avenue, N. W., Washington, D. C.,20009. Document P86‐002; $2.00. Paymentmust accompany order.