气候变化领域集成服务门户(CCPortal): Vegetation change in the Baringo Basin; East Africa across the onset of Northern Hemisphere glaciation 3.3

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DOI	10.1016/j.palaeo.2019.109426
	Vegetation change in the Baringo Basin; East Africa across the onset of Northern Hemisphere glaciation 3.3–2.6 Ma
	Lupien R.L.; Russell J.M.; Yost C.L.; Kingston J.D.; Deino A.L.; Logan J.; Schuh A.; Cohen A.S.
发表日期	2019
ISSN	0031-0182
英文摘要	Vegetation in East Africa is generally thought to have shifted from forests to more open grasslands and savannas as global climate cooled and high-latitude ice sheets expanded during the Plio-Pleistocene. Such a shift would have greatly influenced landscape resources, and potentially hominin evolution as well. Existing records of African vegetation spanning these time-scales are generally derived from offshore marine records that record continental-scale changes, or paleosol carbonate records that record very local vegetation changes during the short time intervals of soil carbonate formation. Here we present a new record of basin-scale vegetation change from the late Pliocene (~3.3–2.6 Ma) derived from a drill core from the Chemeron Formation, located in the Baringo Basin/Tugen Hills region of the Kenya Rift Valley. Specifically, we present a new record of the relative abundance of C4 grasses and C3 vegetation based on the carbon isotopic composition of leaf wax biomarkers (δ13Cwax), which captures a signal of regional vegetation change. These data demonstrate that vegetation in the Baringo Basin varied greatly between C3 forests and C4 grasslands, and that vegetation exhibits both long-term (secular) trends and orbital-scale variations. The contribution of C3 plants was lower than estimates based on low-resolution carbon isotope data from paleosol carbonates and organic matter in the basin. C3 plants averaged ~53% of the vegetation during the late Pliocene, from ~3.3 to ~3.04 Ma, after which time δ13Cwax indicates more open vegetation and ~41% C3 plants. This transition may have been driven by changes in basin geomorphology, but also possibly occurred as part of larger-scale drying and expansion of C4 vegetation in East Africa. In addition to this secular change, we observe high amplitude variability in the δ13Cwax record including oscillations between ~80 and ~0% C3 plants. These vegetation changes are correlated with changes in precipitation inferred from δ2Hwax and lake level oscillations inferred from sedimentary facies, implying that high-amplitude, orbital-scale variations in precipitation drove significant changes in vegetation resources during the late Pliocene in the Baringo Basin. These variations have important implications for changes in terrestrial resources in light of the evolutionary innovations in the hominin fossil record related to changes in foraging strategies. © 2019 Elsevier B.V.
英文关键词	Carbon isotopes; Human evolution; Leaf waxes; Organic geochemistry; Paleoclimatology; Pliocene
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/151188
作者单位	Brown University, Department of Earth, Environmental, and Planetary Sciences, 324 Brooke Street, Providence, RI 02906, United States; Lamont-Doherty Earth Observatory, Division of Biology and Paleo Environment, 61 Route 9W, Palisades, NY 10964, United States; University of Arizona, Department of Geosciences, 1040 East 4th, Street, Tucson, AZ 85721, United States; University of Michigan, Department of Anthropology, 1085 South University Avenue, Ann Arbor, MI 48109, United States; Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, United States
推荐引用方式 GB/T 7714	Lupien R.L.,Russell J.M.,Yost C.L.,等. Vegetation change in the Baringo Basin; East Africa across the onset of Northern Hemisphere glaciation 3.3–2.6 Ma[J],2019.
APA	Lupien R.L..,Russell J.M..,Yost C.L..,Kingston J.D..,Deino A.L..,...&Cohen A.S..(2019).Vegetation change in the Baringo Basin; East Africa across the onset of Northern Hemisphere glaciation 3.3–2.6 Ma.Palaeogeography, Palaeoclimatology, Palaeoecology.
MLA	Lupien R.L.,et al."Vegetation change in the Baringo Basin; East Africa across the onset of Northern Hemisphere glaciation 3.3–2.6 Ma".Palaeogeography, Palaeoclimatology, Palaeoecology (2019).