Initial Reports of the Deep Sea Drilling Project - Volume 13

This volume covers Leg 13 of the cruises of the Drilling Vessel Glomar Challenger. Leg 13 of the Deep Sea Drilling Project was scheduled to explore the origin and development of a small ocean basin—The Mediterranean. The Mediterranean is considered a modern example of a geological feature that has been designated as an intercontinental geosyncline. The rocks of an ancient Mediterranean, also known as the Tethys, are now exposed in the Alpine chains of Europe and Africa, and have provided considerable insight concerning the evolutionary trends of ocean basins of the past. Drilling in the Mediterranean was expected to serve as a link for the integration of existing geological data in the framework of the new discoveries of marine geophysics. Our drilling program was designed to resolve some specific problems and to gather data for the evaluation of various competing hypotheses on the geological history of the Mediterranean. The three major aspects were tectonic, sedimentary, and biostratigraphic. Glomar Challenger left Lisbon, Portugal, at midnight, August 13th, and returned there on the morning of October 6th. Although the principal objectives of Leg 13 were to drill in the Mediterranean, the first site of the cruise was located in the Atlantic, southwest of Portugal, because the late Cenozoic tectonic history of the Mediterranean is closely tied to the development of a plate boundary in the Atlantic along the Azores-Gibraltar seismic belt. The drilling vessel then occupied fourteen sites in the Mediterranean, seven in the western basin and an equal number in the eastern basin. A total of 28 holes were drilled.