气候变化领域集成服务门户(CCPortal): Chronostratigraphy of the Baringo-Tugen Hills-Barsemoi (HSPDP-BTB13-1A) core – 40Ar/39Ar dating; magnetostratigraphy; tephrostratigraphy; sequence stratigraphy and Bayesian age modeling

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DOI	10.1016/j.palaeo.2019.109519
	Chronostratigraphy of the Baringo-Tugen Hills-Barsemoi (HSPDP-BTB13-1A) core – 40Ar/39Ar dating; magnetostratigraphy; tephrostratigraphy; sequence stratigraphy and Bayesian age modeling
	Deino A.L.; Sier M.J.; Garello D.I.; Keller C.B.; Kingston J.D.; Scott J.J.; Dupont-Nivet G.; Cohen A.S.
发表日期	2019
ISSN	0031-0182
英文摘要	The Baringo-Tugen Hills-Barsemoi 2013 drillcore (BTB13), acquired as part of the Hominin Sites and Paleolakes Drilling Project, recovered 228 m of fluvio-lacustrine sedimentary rocks and tuffs spanning a ~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 40Ar/39Ar dating of tuffs from core and outcrop, 40Ar/39Ar 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 3.2–2.9 Ma; a relatively slow phase from 2.9–2.7 Ma; and the highest rate of accumulation from 2.7–2.6 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 ~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. © 2019 Elsevier B.V.
英文关键词	Chemeron Formation; Eccentricity; Paleoclimate; Paleolimnology; Pliocene; Precession
语种	英语
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151187
作者单位	Berkeley Geochronology Center, 2455 Ridge Rd., Berkeley, CA 94709, United States; Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, United Kingdom; CENIEH, Paseo Sierra de Atapuerca 3, 09002, Burgos, Spain; School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, United States; Department of Anthropology, University of Michigan, Ann Arbor, MI 48109, United States; Department of Earth and Environmental Sciences, Mount Royal University, Calgary, Alberta T3E 6K6, Canada; Univ Rennes, CNRS, Géosciences Rennes - UMR 6118, Rennes, F-35000, France; Institute for Earth and Environmental Science, Potsdam University, Potsdam, Germany; Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States
推荐引用方式 GB/T 7714	Deino A.L.,Sier M.J.,Garello D.I.,等. Chronostratigraphy of the Baringo-Tugen Hills-Barsemoi (HSPDP-BTB13-1A) core – 40Ar/39Ar dating; magnetostratigraphy; tephrostratigraphy; sequence stratigraphy and Bayesian age modeling[J],2019.
APA	Deino A.L..,Sier M.J..,Garello D.I..,Keller C.B..,Kingston J.D..,...&Cohen A.S..(2019).Chronostratigraphy of the Baringo-Tugen Hills-Barsemoi (HSPDP-BTB13-1A) core – 40Ar/39Ar dating; magnetostratigraphy; tephrostratigraphy; sequence stratigraphy and Bayesian age modeling.Palaeogeography, Palaeoclimatology, Palaeoecology.
MLA	Deino A.L.,et al."Chronostratigraphy of the Baringo-Tugen Hills-Barsemoi (HSPDP-BTB13-1A) core – 40Ar/39Ar dating; magnetostratigraphy; tephrostratigraphy; sequence stratigraphy and Bayesian age modeling".Palaeogeography, Palaeoclimatology, Palaeoecology (2019).