RESPONSE OF RED-SEA DEEP-WATER AGGLUTINATED FORAMINIFERA TO WATER-MASS CHANGES DURING THE LATE QUATERNARY

The distribution of deep-water agglutinated foraminifera was determine d in core material taken in the central Red Sea by the RN Meteor, crui se 5, leg 2. The sedimentary record represents the last 380 kyr, which includes four glacial/interglacial cycles. The agglutinate assemblage is of low diversity, and in general is a minor component of the benth ic foraminifera. It comprises 14 species belonging to the following ge nera: Ammobaculites, Lagenammina, Plotnikovina, Pseudogaudryina, Reoph ax, Sahulia, Siphotextularia, Spiroplectinella, Textularia and a doubt ful genus of unknown taxonomic position: 'Psammosphaera'. Three sub-gr oups were identified in the core according to their occurrence either in interglacial stages or in both glacial and interglacial intervals, reflecting mainly tolerance to salinity variations. Exceptional bottom -water conditions during the last 60 kyr caused a remarkable decrease inthe abundance and diversity of this group. The development of dysaer obic bottom water between approx. 60 and 26 kyr, the presence of a dee p-water mass of extremely high salinity (ca. 55 parts per thousand) be tween 26 and 13 kyr, and the occurrence of anoxic bottom sediments bet ween 12.9 and 9.6 kyr seem to have caused the extreme impoverishment. During the last 9.6 kyr the agglutinated foraminifera gradually recolo nized the deep water. A diverse assemblage composed of the above menti oned genera is found in Holocene sediments only in the core top sample . In addition, small (63-149 mu m), noncanaliculate organic cemented a gglutinated foraminifera belonging to the genera Ammodiscus, Cribrosto moides, 'Eggerella', Glomospira, Haplophragmoides, Morulaeplecta, Spir oplectammina, Paratrochammina and Trochammina are preserved preferenti ally only in the uppermost part of the core (0-28 cm depth), in sedime nts younger than 3 kyr.