Microtektites in the Middle Pleistocene deep-sea sediments of the South China Sea

This is a preliminary study on the microtektites that were found in large numbers from the interval between 7.80 and 8.10 m depth of core SO95-17957-2 (10 degrees 53.9'N, 115 degrees 18.3'E, water depth 2 195 m), northern Nansha area of the South China Sea. The microtektites vary in shape, with spherules predominating, and are commonly less than 1 mm in diameter, transparent or semitransparent, brownish in color, with bubbles inside. Based on coarse fraction stratigraphy and foraminifera/nanofossil biostratigraphical events the microtektite layer was assigned to nearly the Brunhes/Matuyama magnetic reversal boundary (some 0.78 MaBP). Obviously, the present microtektites, and those found from the middle Pleistocene of the Indian Ocean, Australia and loess of northern China, were products of the same impact event and therefore, are useful as a reliable mark in Quaternary stratigraphy, as well as in paleoclimatic studies.