Paleoclimatic variations in West Africa from a record of late Pleistocene and Holocene lake level stands of Lake Bosumtwi, Ghana Export

@article{citeulike:968433, abstract = {A detailed investigation of geomorphological evidence of paleoshorelines and exposed stratigraphic sections of lake deposits, combined with a chronology based on radiocarbon dated charcoal and in-situ 14C dating of wave polished bedrock, provide important new constraints on lake level changes of Lake Bosumtwi, Ghana. Thick sequences of laminated silts, alternating with transgressive sands and deltaic gravels, attest to a long history of climatically controlled lake level variations. The post-glacial rise in lake level began sometime after 16.3[no-break space]ka, reached stable levels first at 14.5 +/- 0.6[no-break space]ka and then rose again after ca. 14.3[no-break space]ka. A significant lake level regression spanned the interval from 12.6 +/- 0.3 to 11.6 +/- 0.5[no-break space]ka, synchronous with the Younger Dryas. Deep lake conditions were reestablished after ca. 11 ka, at which time the lake overtopped the crater. Overflow continued until 8.8 +/- 0.5[no-break space]ka, when another significant but short-lived regression occurred. Deep, but probably not overflowing conditions were again reestablished by > 7.2 +/- 0.3[no-break space]ka and continued until around 3.2 +/- 0.1[no-break space]ka, when lake level dropped precipitously. Multicentury late Holocene highstands occurred at 2.2 +/- 0.1 and 1.7 +/- 0.2[no-break space]ka, although these were significantly lower than those registered in the late glacial and early Holocene. The timing of late glacial events is similar to those recorded elsewhere in Africa and the higher latitudes, and likely reflects the dominant control of high latitude northern hemisphere conditions on the African tropics during the times of large northern hemisphere ice sheets. Mid- to late-Holocene variations appear to be less coupled with changes across Africa and elsewhere, suggesting that regional forcing may be more important during warmer periods.}, author = {Shanahan, Timothy M. and Overpeck, Jonathan T. and Wheeler, Winston C. and Beck, Warren J. and Pigati, Jeffrey S. and Talbot, Michael R. and Scholz, Christopher A. and Peck, John and King, John W.}, citeulike-article-id = {968433}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/j.palaeo.2006.06.007}, citeulike-linkout-1 = {http://www.sciencedirect.com/science/article/B6V6R-4KKFPM5-1/2/0959aa9c1104164de071bcc49d95e44d}, day = {8}, doi = {10.1016/j.palaeo.2006.06.007}, journal = {Palaeogeography, Palaeoclimatology, Palaeoecology}, keywords = {200611, afrique\_de\_l\_ouest, climat, holocene, pleistocene}, month = {December}, number = {3-4}, pages = {287--302}, posted-at = {2006-11-30 10:23:23}, priority = {2}, title = {Paleoclimatic variations in West Africa from a record of late Pleistocene and Holocene lake level stands of Lake Bosumtwi, Ghana}, url = {http://dx.doi.org/10.1016/j.palaeo.2006.06.007}, volume = {242}, year = {2006} }

TY - JOUR ID - citeulike:968433 L3 - citeulike-article-id:968433 N2 - A detailed investigation of geomorphological evidence of paleoshorelines and exposed stratigraphic sections of lake deposits, combined with a chronology based on radiocarbon dated charcoal and in-situ 14C dating of wave polished bedrock, provide important new constraints on lake level changes of Lake Bosumtwi, Ghana. Thick sequences of laminated silts, alternating with transgressive sands and deltaic gravels, attest to a long history of climatically controlled lake level variations. The post-glacial rise in lake level began sometime after 16.3[no-break space]ka, reached stable levels first at 14.5 +/- 0.6[no-break space]ka and then rose again after ca. 14.3[no-break space]ka. A significant lake level regression spanned the interval from 12.6 +/- 0.3 to 11.6 +/- 0.5[no-break space]ka, synchronous with the Younger Dryas. Deep lake conditions were reestablished after ca. 11 ka, at which time the lake overtopped the crater. Overflow continued until 8.8 +/- 0.5[no-break space]ka, when another significant but short-lived regression occurred. Deep, but probably not overflowing conditions were again reestablished by > 7.2 +/- 0.3[no-break space]ka and continued until around 3.2 +/- 0.1[no-break space]ka, when lake level dropped precipitously. Multicentury late Holocene highstands occurred at 2.2 +/- 0.1 and 1.7 +/- 0.2[no-break space]ka, although these were significantly lower than those registered in the late glacial and early Holocene. The timing of late glacial events is similar to those recorded elsewhere in Africa and the higher latitudes, and likely reflects the dominant control of high latitude northern hemisphere conditions on the African tropics during the times of large northern hemisphere ice sheets. Mid- to late-Holocene variations appear to be less coupled with changes across Africa and elsewhere, suggesting that regional forcing may be more important during warmer periods. IS - 3-4 JF - Palaeogeography, Palaeoclimatology, Palaeoecology EP - 302 TI - Paleoclimatic variations in West Africa from a record of late Pleistocene and Holocene lake level stands of Lake Bosumtwi, Ghana VL - 242 SP - 287 KW - 200611 KW - afrique_de_l_ouest KW - climat KW - holocene KW - pleistocene AU - Shanahan, Timothy AU - Overpeck, Jonathan AU - Wheeler, Winston AU - Beck, Warren AU - Pigati, Jeffrey AU - Talbot, Michael AU - Scholz, Christopher AU - Peck, John AU - King, John PY - 2006/12/08/ UR - http://dx.doi.org/10.1016/j.palaeo.2006.06.007 ER -