PALEOCEANOGRAFIA DE BAHíA MEJILLONES DEL SUR (ANTOFAGASTA) CHILE): RESULTADOS PRELIMINARES PARA EL ÚLTIMO MlLENlO PALEOCEANOGRAPHY OF BAHIA MEJILLONES DEL SUR (ANTOFAGASTA) CHILE): PRELIMINARY RESULTS FOR THE LAST MILLENNIUM.

A stratigraphic study of marine sediments from Bahia de Mejillones del Sur (23's) is meant to reveal secular/millennial variations in the oceanographic and climatic conditions in the arid north coast of Chile. A series of dredging samples and gravity cores (up to 1 m long) were thus obtained. Preliminary results of a qualitative and quantitative study of fish remains, foraminifers, diatoms and silicoflagellates from two short gravity cores (35 cm long) which encompass approximately 1000 yr of sedimentation, confirm the good preservation of the sub-fossil material and its potential for the reconstitution of oceanographic changes. The occurrence and relative composition of some bioindicators in the distinct layers of the cores leads to interpret significant variations in the upwelling system, the thermal regime and the oxygen content at the bottom of the bay in the course of the last ten centuries.