Initial Reports of the Deep Sea Drilling Project - Volume 24

This volume covers Leg 24 of the cruises of the Drilling Vessel Glomar Challenger. The principal aims of Leg 24, between Djibouti (F.T.A.I), at the western end of the Gulf of Aden, and the island of Mauritius, at the southern end of the Mascarene Plateau, were in part dictated by the three distinct geographic areas to be examined. Glomar Challenger traversed the Gulf of Aden, the northwest Somali Basin, and the Mascarene Plateau-Central Indian Ridge-Chagos-Laccadive Ridge complex. Common to all sites was the study of the sediments, their sources, and the role of depositional processes in the early stages of ocean development in the Gulf of Aden, in the magnetically quiet zone of the deep Somali Abyssal Plain, in the deep region north of the Seychelles and south of the Carlsberg Ridge, and between the Mascarene Plateau and Chagos-Laccadive Ridge. Continuous coring of selected low-latitude sites has resulted in the preparation of paleontological reference columns for the western Indian Ocean. Sampling, as fully as possible, continuous sections at basement-contact zones detected late-stage volcanic effects and better established a paleontological date for any magnetic anomaly lineation recognized. Drilling in igneous rock was carried deep enough to establish whether or not the rock was "basement" and to obtain fresh (unweathered) samples. Furthermore, by penetrating more than superficially into nonpyroclastic volcanic materials, attempts were made to establish and evaluate structural and textural criteria for presumed pillow and flow occurrences, to examine thickness, jointing, and fluidity of submarine flows and to assess significance of datable or metamorphosed sedimentary inclusions or joint fillings. Leg 24 began in Djibouti (F.T.A.I) in May, 1972 and ended in Port Louis, Mauritius in June, 1972.