A NEW MIDDLE PLEISTOCENE CHRONOLOGY FOR KENT'S CAVERN, ENGLAND

Kent's Cavern is one of Britain's most famous Pleistocene archaeological and paleontological sites, with a rich historical legacy dating back to original excavations by the Rev. J. MacEnery in 1825. Subsequent excavations by William Pengelly between 1865 and 1880 have left exposed as much as 4m of autochthonous and allochthonous stratigraphy including a rich late Pleistocene fauna bracketed by thick flowstone deposits. Kent's Cavern lay south of the ice margin during each of the glaciations of the middle and late Pleistocene, although evidence of strong frost action is recorded in the speleothems. The most important paleontological deposit in the cave is a basal, cold-climate debris flow which contains abundant remains of a primitive grade of the cave bear, Ursus deningeri –U. spelaeus, taxa that are rare in British caves. This “breccia” deposit has previously proven recalcitrant to direct radiometric dating, but recent efforts by TIMS and ICPMS U/Th disequilibrium dating of some 40 samples of overlying and incorporated speleothem deposits have elucidated the complex stratigraphy, despite the technical challenges of low uranium and high detrital content. Extensive speleothem deposition occurred in each of the interglacials of MIS 5, 7, 9 and 11, with much MIS 11 material apparently being eroded during the MIS 10 glacial. We have demonstrated that the cave bear remains of the famous Kent's Cavern breccia and associated human flint artifacts are most parsimoniously assigned to MIS 12 (Anglian glaciation), a little later than the famous paleoanthropological site at Boxgrove but older than the Swanscombe site.