@misc{CohenCampisanoArrowsmithetal.2016, author = {Cohen, Abby and Campisano, Christopher and Arrowsmith, J. Ramon and Asrat, Asfawossen and Behrensmeyer, A. K. and Deino, A. and Feibel, C. and Hill, A. and Johnson, R. and Kingston, J. and Lamb, Henry F. and Lowenstein, T. and Noren, A. and Olago, D. and Owen, Richard Bernhart and Potts, R. and Reed, Kate and Renaut, R. and Sch{\"a}bitz, F. and Tiercelin, J.-J. and Trauth, Martin H. and Wynn, J. and Ivory, S. and Brady, K. and O'Grady, R. and Rodysill, J. and Githiri, J. and Russell, Joellen and Foerster, Verena and Dommain, Ren{\´e} and Rucina, J. S. and Deocampo, D. and Russell, J. and Billingsley, A. and Beck, C. and Dorenbeck, G. and Dullo, L. and Feary, D. and Garello, D. and Gromig, R. and Johnson, T. and Junginger, Annett and Karanja, M. and Kimburi, E. and Mbuthia, A. and McCartney, Tannis and McNulty, E. and Muiruri, V. and Nambiro, E. and Negash, E. W. and Njagi, D. and Wilson, J. N. and Rabideaux, N. and Raub, Timothy and Sier, Mark Jan and Smith, P. and Urban, J. and Warren, M. and Yadeta, M. and Yost, Chad and Zinaye, B.}, title = {The Hominin Sites and Paleolakes Drilling Project}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {611}, doi = {10.25932/publishup-41249}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-412498}, pages = {16}, year = {2016}, abstract = {The role that climate and environmental history may have played in influencing human evolution has been the focus of considerable interest and controversy among paleoanthropologists for decades. Prior attempts to understand the environmental history side of this equation have centered around the study of outcrop sediments and fossils adjacent to where fossil hominins (ancestors or close relatives of modern humans) are found, or from the study of deep sea drill cores. However, outcrop sediments are often highly weathered and thus are unsuitable for some types of paleoclimatic records, and deep sea core records come from long distances away from the actual fossil and stone tool remains. The Hominin Sites and Paleolakes Drilling Project (HSPDP) was developed to address these issues. The project has focused its efforts on the eastern African Rift Valley, where much of the evidence for early hominins has been recovered. We have collected about 2 km of sediment drill core from six basins in Kenya and Ethiopia, in lake deposits immediately adjacent to important fossil hominin and archaeological sites. Collectively these cores cover in time many of the key transitions and critical intervals in human evolutionary history over the last 4 Ma, such as the earliest stone tools, the origin of our own genus Homo, and the earliest anatomically modern Homo sapiens. Here we document the initial field, physical property, and core description results of the 2012-2014 HSPDP coring campaign.}, language = {en} } @article{DeinoSierGarelloetal.2019, author = {Deino, Alan L. and Sier, Mark Jan and Garello, Dominique and Keller, B. and Kingston, John and Scott, Jennifer J. and Dupont-Nivet, Guillaume and Cohen, Andrew}, title = {Chronostratigraphy of the Baringo-Tugen-Barsemoi (HSPDP-BTB13-1A) core-Ar-40/Ar-39 dating, magnetostratigraphy, tephrostratigraphy, sequence stratigraphy and Bayesian age modeling}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {532}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2019.109258}, pages = {16}, year = {2019}, abstract = {The Baringo-Tugen-Barsemoi 2013 drillcore (BTB13), acquired as part of the Hominin Sites and Paleolakes Drilling Project, recovered 228 m of fluviolacustrine sedimentary rocks and tuffs spanning a similar to 3.29-2.56 Ma interval of the highly fossiliferous and hominin-bearing Chemeron Formation, Tugen Hills, Kenya. Here we present a Bayesian stratigraphic age model for the core employing chronostratigraphic control points derived from Ar-40/Ar-39 dating of tuffs from core and outcrop, Ar-40/Ar-39 age calibration of related outcrop diatomaceous units, and core magnetostratigraphy. The age model reveals three main intervals with distinct sediment accumulation rates: an early rapid phase from 3.2 to 2.9 Ma; a relatively slow phase from 2.9 to 2.7 Ma; and the highest rate of accumulation from 2.7 to 2.6 Ma. The intervals of rapid accumulation correspond to periods of high Earth orbital eccentricity, whereas the slow accumulation interval corresponds to low eccentricity at 2.9-2.7 Ma, suggesting that astronomically mediated climate processes may be responsible for the observed changes in sediment accumulation rate. Lacustrine transgression-regression events, as delineated using sequence stratigraphy, dominantly operate on precession scale, particularly within the high eccentricity periods. A set of erosively based fluvial conglomerates correspond to the 2.9-2.7 Ma interval, which could be related to either the depositional response to low eccentricity or to the development of unconformities due to local tectonic activity. Age calibration of core magnetic susceptibility and gamma density logs indicates a close temporal correspondence between a shift from high- to low-frequency signal variability at similar to 3 Ma, approximately coincident the end of the mid-Piacenzian Warm Period, and the beginning of the cooling of world climate leading to the initiation of Northern Hemispheric glaciation c. 2.7 Ma. BTB13 and the Baringo Basin records may thus provide evidence of a connection between high-latitude glaciation and equatorial terrestrial climate toward the end of the Pliocene.}, language = {en} }