Stratigraphic and paleoceanographic significance of Late Quaternary pteropods from deep-sea cores in the Gulf of Aqaba (Elat) and northernmost Red Sea

The quantitative distribution of 16 thecosomatous pteropod species from four deep-sea cores recovered from the Gulf of Aqaba (Elat) and northernmost Red Sea is summarized. The distribution facilitates a relatively high resolution stratigraphic subdivision of the 6-8 m long core sequences and their correlation. The sequences of pteropod assemblages can be related to oxygen isotope curves and thus dated beyond the radiocarbon-range. The oldest strata penetrated are dated at about 150,000 yr B.P. Considering the present-day distribution of the species recognized, the core assemblages are of a tropical-subtropical character throughout the Late Quaternary. On the basis of the composition of the living pteropod populations in the hypersaline (41%.), moderately oligotrophic and desert-enclosed Gulf of Aqaba, the pteropod core assemblages, associated foraminiferal assemblages, and the oxygen isotope values determined on both groups, a sequence of paleoceanographic changes during the Late Quaternary is derived. These changes are primarily influenced by productivity of the waters and pertain less to temperature and salinity. The glacial periods (isotope stages 2,3,4 and upper 6) were characterized by lower temperature than at present, higher salinity and greater fertility of the waters. During the glacial maxima monospecific Creseis acicula assemblages characterize periods of metahaline (more than 50%. salinity) conditions in highly productive waters. Although not identical in detail, the last interglacial (stage 5) assemblages are similar to the Holocene warm-water oligotrophic ones. Between 8000 and 3000 yr B.P. a short period of slightly higher productivity is indicated.