A MIDDLE PLEISTOCENE GLACIAL-INTERGLACIAL SUCCESSION IN THE INNER SILVER PIT, SOUTHERN NORTH-SEA - FORAMINIFERAL STRATIGRAPHY AND AMINO-ACID GEOCHRONOLOGY

Benthic foraminiferal data from the depth interval between 42.0 and 30 .5 m in the Inner Silver Pit core 81/52A in the southern North Sea has revealed a glacial-interglacial succession comprising a 5 m thick int erglacial deposit. The foraminiferal assemblages initially indicate ic e-proximal conditions (Zone 52-1) from a deglaciation period. A transi tional zone (Zone 52-2) with faunal indication of relatively deeper wa ter and slightly higher but still subarctic temperature conditions, is followed by a true interglacial succession (called the Inner Silver P it Interglacial) with increased faunal diversity and with a high conte nt of warm water species (Zone 52-3). A decrease in water depth is reg istered towards the top of the interglacial succession. The assemblage in the topmost sample (Zone 52-4) indicates a return to high arctic g lacial marine conditions. Foraminiferal faunas in three vibrocores obt ained from the slopes of the neighbouring Inner Silver Pit valley are correlated with the interglacial assemblages in Zone 52-3 and with the succeeding glacial marine Zone 52-4 of the Inner Silver Pit core 81/5 2A. Based on the degree of isoleucine epimerisation in benthic foramin ifera the interglacial deposit is referred to the Middle Pleistocene, and a correlation with oxygen isotope stage 9 is suggested. (C) 1998 P ublished by Elsevier Science Ltd. All rights reserved.