Tidal deposits. A casebook of recent examples and fossil counterparts: R.N. Ginsburg (editor). Springer,Berlin, 1975, 428 pp., US $ 34.80

Pollen and foraminifera were analyzed from identical samples in two marine cores taken from the upper and lower continental rise between Cape Hatteras and Chesapeake Bay. Down-core variations in percent abundance of pollen taxa permit the identification of three floral events. These floral events are comparable to and isochronous with changes in polleniferous sediments from the adjacent continental United States through the last 20,000 y, the time interval represented in these cores.A transfer function was used to obtain sea surface paleotemperature estimates from planktonic foraminifera. These estimates indicate that surface waters were relatively warm at the site of both cores from 8,000 y BP to present. Between 12,400 and 8,000 y BP the nearshore core continued to record warm temperatures whereas the offshore core, which should be closer to warm Gulf Stream waters, seems to have recorded significantly colder temperatures. These temperature discrepancies appear to result from severe carbonate dissolution in the offshore core. Temperature estimates are lowered by dissolution of the less resistant tropical species leaving resistant transitional and subpolar forms. This dissolution event coincides with the maximum upslope movement of the Western Boundary Undercurrent as indicated by changes in sedimentation rate.As shown by the nearshore core, in which dissolution was not severe, surface temperatures in this area increased abruptly about 12,000 y BP and remained relatively warm until 4,000 y BP when they decreased slightly. These changes in sea surface temperature appear to be related to the position of the Gulf Stream as indicated by percent abundance of Globigerinoides sacculifer. The Gulf Stream moved into this area about 12,000 y BP and attained its maximum northward penetration about 8,000 y BP.Marine and terrestrial paleoclimatic changes in this area are not synchronous. Sea surface temperatures increased about 12,000 y BP whereas the change from a glacial to an interglacial forest occurred several thousand years later, about 10,000 y BP.