TY - JOUR A1 - Deino, A. L. A1 - Dommain, René A1 - Keller, C. B. A1 - Potts, R. A1 - Behrensmeyer, A. K. A1 - Beverly, E. J. A1 - King, J. A1 - Heil, C. W. A1 - Stockhecke, M. A1 - Brown, E. T. A1 - Moerman, J. A1 - deMenocal, P. A1 - Deocampo, D. A1 - Garcin, Yannick A1 - Levin, N. E. A1 - Lupien, R. A1 - Owen, R. B. A1 - Rabideaux, N. A1 - Russell, J. M. A1 - Scott, J. A1 - Riedl, S. A1 - Brady, K. A1 - Bright, J. A1 - Clark, J. B. A1 - Cohen, A. A1 - Faith, J. T. A1 - Noren, A. A1 - Muiruri, V. A1 - Renaut, R. A1 - Rucina, S. A1 - Uno, K. T1 - Chronostratigraphic model of a high-resolution drill core record of the past million years from the Koora Basin, south Kenya Rift: Overcoming the difficulties of variable sedimentation rate and hiatuses JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - The Olorgesailie Drilling Project and the related Hominin Sites and Paleolakes Drilling Project in East Africa were initiated to test hypotheses and models linking environmental change to hominin evolution by drilling lake basin sediments adjacent to important archeological and paleoanthropological sites. Drill core OL012-1A recovered 139 m of sedimentary and volcaniclastic strata from the Koora paleolake basin, southern Kenya Rift, providing the opportunity to compare paleoenvironmental influences over the past million years with the parallel record exposed at the nearby Olorgesailie archeological site. To refine our ability to link core-to-outcrop paleoenvironmental records, we institute here a methodological framework for deriving a robust age model for the complex lithostratigraphy of OL012-1A. Firstly, chronostratigraphic control points for the core were established based on 4 Ar/39Ar ages from intercalated tephra deposits and a basal trachyte flow, as well as the stratigraphic position of the Brunhes-Matuyama geomagnetic reversal. This dataset was combined with the position and duration of paleosols, and analyzed using a new Bayesian algorithm for high-resolution age-depth modeling of hiatus-bearing stratigraphic sections. This model addresses three important aspects relevant to highly dynamic, nonlinear depositional environments: 1) correcting for variable rates of deposition, 2) accommodating hiatuses, and 3) quantifying realistic age uncertainty with centimetric resolution. Our method is applicable to typical depositional systems in extensional rifts as well as to drill cores from other dynamic terrestrial or aquatic environments. We use the core age model and lithostratigraphy to examine the inter connectivity of the Koora Basin to adjacent areas and sources of volcanism. (C) 2019 Elsevier Ltd. All rights reserved. KW - Pleistocene KW - Paleolimnology KW - East Africa KW - Sedimentology KW - Radiogenic isotopes KW - Bayesian modeling KW - paleosol KW - Tephrostratigraphy KW - Magnetostratigraphy KW - Kenya Rift Y1 - 2019 U6 - https://doi.org/10.1016/j.quascirev.2019.05.009 SN - 0277-3791 VL - 215 SP - 213 EP - 231 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Lepetit, Petra A1 - Viereck, Lothar A1 - Piper, John D. A. A1 - Sudo, Masafumi A1 - Gurel, Ali A1 - Copuroglu, Ibrahim A1 - Gruber, Manuela A1 - Mayer, Bernhard A1 - Koch, Michael A1 - Tatar, Orhan A1 - Gursoy, Halil T1 - Ar-40/Ar-39 dating of ignimbrites and plinian air-fall layers from Cappadocia, Central Turkey: Implications to chronostratigraphic and Eastern Mediterranean palaeoenvironmental record JF - Chemie der Erde : interdisciplinary journal for chemical problems of the geo-sciences and geo-ecology N2 - Magmatism forming the Central Anatolian Volcanic Province of Cappadocia, central Turkey, records the last phase of Neotethyan subduction after similar to 11 Ma. Thirteen large calc-alkaline ignimbrite sheets form marker bands within the volcano-sedimentary succession (the Urgup Formation) and provide a robust chronostratigraphy for paleoecologic evaluation of the interleaved paleosols. This paper evaluates the chronologic record in the context of the radiometric, magnetostratigraphic and lithostratigraphic controls. Previous inconsistencies relating primarily to K/Ar evidence were reason for the initiation of an integrated study which includes Ar-40/Ar-39 dating, palaeomagnetic and stratigraphic evidence. The newly determined Ar-40/Ar-39-ages (Lepetit, 2010) are in agreement with Ar/Ar and U/Pb data meanwhile published by Pauquette and Le Pennec (2012) and Aydar et al. (2012). The Ar-40/Ar-39-ages restrict the end of the Urgup Formation to the late Miocene. The paleosol sequence enclosed by the ignimbrites is thus restricted to the late Miocene, the most intense formation of pedogene calcretes correlating with the Messinian Salinity Crisis. KW - Ar-40/Ar-39 dating KW - Tephrostratigraphy KW - Neogene KW - Cappadocia KW - Turkey Y1 - 2014 U6 - https://doi.org/10.1016/j.chemer.2014.05.001 SN - 0009-2819 SN - 1611-5864 VL - 74 IS - 3 SP - 471 EP - 488 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Sirocko, Frank A1 - Dietrich, Stephan A1 - Veres, Daniel A1 - Grootes, Pieter M. A1 - Schaber-Mohr, Katja A1 - Seelos, Klemens A1 - Nadeau, Marie-Josee A1 - Kromer, Bernd A1 - Rothacker, Leo A1 - Roehner, Marieke A1 - Krbetschek, Matthias A1 - Appleby, Peter G. A1 - Hambach, Ulrich A1 - Rolf, Christian A1 - Sudo, Masafumi A1 - Grim, Stephanie T1 - Multi-proxy dating of Holocene maar lakes and Pleistocene dry maar sediments in the Eifel, Germany JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - During the last twelve years the ELSA Project (Eifel Laminated Sediment Archive) at Mainz University has drilled a total of about 52 cores from 27 maar lakes and filled-in maar basins in the Eifel/Germany. Dating has been completed for the Holocene cores using 6 different methods (Pb-210 and Cs-137 activities, palynostratigraphy, event markers, varve counting, C-14) In general, the different methods consistently complement one another within error margins. Event correlation was used for relating typical lithological changes with historically known events such as the two major Holocene flood events at 1342 AD and ca 800 BC. Dating of MIS2-MIS3 core sections is based on greyscale tuning, radiocarbon and OSL dating, magnetostratigraphy and tephrochronology. The lithological changes in the sediment cores demonstrate a sequence of events similar to the North Atlantic rapid climate variability of the Last Glacial Cycle. The warmest of the MIS3 interstadials was GI14, when a forest with abundant spruce covered the Eifel area from 55 to 48 ka BP, i.e. during a time when also other climate archives in Europe suggested very warm conditions. The forest of this "Early Stage 3 warm phase" developed subsequently into a steppe with scattered birch and pine, and finally into a glacial desert at around 25 ka BP. Evidence for Mono Lake and Laschamp geomagnetic excursions is found in two long cores. Several large eruptions during Middle and Late Pleistocene (Ulmener Maar - 11,000 varve years BP, Laacher See - 12,900 varve years BP, Mosenberg volcanoes/Meerfelder Maar 41-45 cal ka BP, Dumpel Maar 116 ka BP, Glees Maar - 151 ka BP) produced distinct ash-layers crucial for inter-core and inter-site correlations. The oldest investigated maar of the Eifel is Ar-40/Ar-39 dated to the time older than 520 ka BP. KW - Eifel maar KW - Laminated lake sediments KW - Tuning KW - Historical events KW - C-14-derived chronology KW - Varve counting KW - Luminescence dating KW - Palynostratigraphy KW - (CS)-C-137 and Pb-210 dating KW - Palaeomagnetism KW - Tephrostratigraphy KW - Argon-Argon dating KW - GIS Y1 - 2013 U6 - https://doi.org/10.1016/j.quascirev.2012.09.011 SN - 0277-3791 VL - 62 SP - 56 EP - 76 PB - Elsevier CY - Oxford ER -