Chemical alteration of the Pleistocene sediments under influence basaltic sills in the Guaymas Basin, Gulf of California

Abstract

In Guaymas Basin of the Gulf of California Holes DSDP 478 и 481A were drilled (Ocean Drilling Program). Studying of the cores from the holes showed the alteration of chemical composition of sediments in zones of contacts with basaltic sills. In the altered sediments strong decreased content in the Corg. Especially strong it occurs in sediment, that is located between sills in complex of thin sills. In these sediments also strong decreased contentin the Li, Cu, As, Mo, Ag, Cd, Sb, Ta, W, Tl, Pb, Bi.For the first time in Upper Pleistocene sediments altered under conditions short-time hydrothermal systems that were formed by intruded sills into sediment cover was analysis wide spectrum of microelements, including rare earth elements.