气候变化领域集成服务门户(CCPortal): Biogeochemical evidence from OGCP Core 2A sediments for environmental changes preceding deposition of Tuff IB and climatic transitions in Upper Bed I of the Olduvai Basin

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DOI	10.1016/j.palaeo.2020.109824
	Biogeochemical evidence from OGCP Core 2A sediments for environmental changes preceding deposition of Tuff IB and climatic transitions in Upper Bed I of the Olduvai Basin
	Shilling A.M.; Colcord D.E.; Karty J.; Hansen A.; Freeman K.H.; Njau J.K.; Stanistreet I.G.; Stollhofen H.; Schick K.D.; Toth N.; Brassell S.C.
发表日期	2020
ISSN	0031-0182
卷号	555
英文摘要	Sediment cores recovered by the Olduvai Gorge Coring Project (OGCP) in 2014 afford the opportunity to examine the coupling of biogeochemical evidence for climatic and environmental change within the context of hominin evolution at this renowned East African locality. Investigations of elemental (total organic carbon – TOC or Corg wt%, carbon to nitrogen ratio - C/N), molecular (source-specific biomarkers), and isotopic (δ13Corg, δ2HnC31) compositions of organic matter provide evidence for temporal changes in sedimentary materials derived from terrestrial plants (C3, C4) and aquatic producers (algae, sponges, cyanobacteria), and in precipitation. The 13 kyr record of Upper Bed I immediately preceding Tuff IB extends high-resolution stratigraphic profiles of precession-scale alternations of wetter and drier conditions to encompass the entire interval from the Bed I Basalt to Tuff IB. The second wetter interval, designated W2, records local influences on climate and water supply consistent with evidence for discrete sediment sources based its physical properties (e.g., gamma radiation, magnetic susceptibility) compared with the overall sequence. The δ13CTOC values for wetter interval W2 reveal two millennial-scale (~2.5 kyr) drier episodes followed by a shift in the dominance of C3 over C4 plants accompanying the transition to a drier climate (D3). Moreover, biogeochemical data for Upper Bed I show that changes from drier to wetter conditions occur more rapidly (~900 yr) than wetter to drier transitions (>2.6 kyr), based on interpolated ages. In addition, biomarker profiles indicate that aquatic plants, primarily algae and macrophytes, may have been subject to more profound and faster fluctuations than variations in terrestrial vegetation expressed in terms of the relative proportions of woodland and grassland settings. Thus, environmental and climatic changes not only influenced the availability of resources of food and shelter for hominins within the Olduvai region but also led to their variation on centennial to millennial to precessional timescales. © 2020
英文关键词	Biomarkers; EARS; n-alkanes; Paleoclimate; Tanzania
语种	英语
scopus关键词	alga; biogeochemistry; biomarker; cyanobacterium; hominid; organic matter; paleoclimate; paleoenvironment; sediment chemistry; sediment core; sponge; Arusha [Tanzania]; East Africa; Olduvai Gorge; Tanzania; algae; Cyanobacteria
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/150406
作者单位	Department of Earth and Atmospheric Sciences, Indiana University, Bloomington, IN, United States; Department of Chemistry, Indiana University, Bloomington, IN, United States; Department of Geosciences, The Pennsylvania State University, University ParkPA, United States; The Stone Age Institute, Gosport, IN, United States; Department of Earth, Ocean, and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom; GeoZentrum Nordbayern, Fredrich-Alexander-Universität (FAU), Erlangen, Germany; Department of Anthropology, Indiana University, Bloomington, IN, United States
推荐引用方式 GB/T 7714	Shilling A.M.,Colcord D.E.,Karty J.,et al. Biogeochemical evidence from OGCP Core 2A sediments for environmental changes preceding deposition of Tuff IB and climatic transitions in Upper Bed I of the Olduvai Basin[J],2020,555.
APA	Shilling A.M..,Colcord D.E..,Karty J..,Hansen A..,Freeman K.H..,...&Brassell S.C..(2020).Biogeochemical evidence from OGCP Core 2A sediments for environmental changes preceding deposition of Tuff IB and climatic transitions in Upper Bed I of the Olduvai Basin.Palaeogeography, Palaeoclimatology, Palaeoecology,555.
MLA	Shilling A.M.,et al."Biogeochemical evidence from OGCP Core 2A sediments for environmental changes preceding deposition of Tuff IB and climatic transitions in Upper Bed I of the Olduvai Basin".Palaeogeography, Palaeoclimatology, Palaeoecology 555(2020).