The Devensian periglacial record on Thanet, Kent, is traced from c. 88 to 74 ka and from c. 24 to 12 ka by optical luminescence dating of aeolian sand and silt in the periglacial stratigraphy. The record commences before 88 ka with valley cutting at Pegwell Bay. Valley filling had begun by c. 88 ka and continued to at least 74 ka, coinciding with a major episode of loess deposition in Europe. Permafrost aggradation commenced before c. 21 ka, brecciating near-surface chalk by ice segregation in permafrost and the overlying active layer. Deposition of aeolian sand (coversand) occurred at c. 24 21 ka, correlating with the Older Coversand I in mainland Europe. Permafrost degradation commenced at c. 21 ka, probably due to climate warming during Greenland Interstadial 2. The resulting active-layer deepening through ice-rich permafrost initiated soft-sediment deformation and formation of large-scale patterned ground in an active layer c. 2m deep. Renewed permafrost aggradation between c. 21.25 and 18 ka coincided with climate cooling during Greenland Stadial 2c and led to cryoturbation in a thinner active layer. Final permafrost degradation commenced no later than c. 14.7 ka, that is, the start of Greenland Interstadial 1e, and may have occurred to some extent during the climate warming associated with Greenland Stadial 2b (c. 19.5 16.9 ka). Renewed deposition of aeolian sand took place at c. 15.5 ka, coincident with loess deposition on Thanet. A final episode of aeolian sand deposition occurred at 12 ka, correlating with the Younger Coversand deposits that are widespread in northwest Europe and formed during Greenland Stadial 1.
|Number of pages||30|
|Journal||Permafrost and Periglacial Processes|
|Publication status||Published - Aug 2003|
- active layer
- aeolian activity
- luminescence dating