Vegetation change in the Baringo Basin, East Africa across the onset of Northern Hemisphere glaciation 3.3–2.6 Ma
Vegetation change in the Baringo Basin, East Africa across the onset of Northern Hemisphere glaciation 3.3–2.6 Ma
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北半球冰川爆发3.3-2.6Ma期间东非巴林戈盆地的植被变化
DOI：
10.1016/j.palaeo.2019.109426
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Cohen, Andrew S.
中科院分区：
文献类型：
--
作者：
Lupien, Rachel L.;Russell, James M.;Yost, Chad L.;Kingston, John D.;Deino, Alan L.;Logan, Jon;Schuh, Anna;Cohen, Andrew S.
人们普遍认为，随着全球气候变冷，高纬度冰盖在上新世-更新世期间扩张，东非的植被已经从森林转向更开阔的草原和稀树草原。这样的转变将极大地影响景观资源，也可能影响人类的进化。现有的非洲植被记录跨越这些时间尺度，通常来自记录大陆尺度变化的近海海洋记录，或记录土壤碳酸盐形成的短时间间隔内非常局部的植被变化的古土壤碳酸盐记录。本文介绍了肯尼亚大裂谷Baringo盆地/Tugen丘陵地区Chemeron组岩心的上新世晚期（~3.3 ~ 2.6 Ma）盆地尺度植被变化的新记录。基于叶蜡生物标志物δ13Cwax的碳同位素组成，给出了c4禾草和c3植被相对丰度的新记录，这是区域植被变化的信号。这些数据表明，Baringo盆地的植被在c3森林和c4草原之间存在很大差异，并且植被既有长期（长期）趋势，也有轨道尺度变化。c3植物的贡献低于基于盆地古土壤碳酸盐和有机质低分辨率碳同位素数据的估计。在上新世晚期~3.3 ~ ~3.04 Ma， c3植物平均占植被的~53%，之后δ 13cwax表明植被更加开阔，c3植物占~41%。这种转变可能是由盆地地貌的变化驱动的，但也可能是东非更大规模的干旱和植被扩张的一部分。除了这种长期变化外，我们还观察到δ 13cwax记录的高振幅变异性，包括在~ 80%和~0% c3植物之间的振荡。这些植被变化与δ 2hwaxz推断的降水变化和沉积相推断的湖平面振荡相关，表明在上新世晚期，高振幅、轨道尺度的降水变化驱动了Baringo盆地植被资源的显著变化。鉴于与觅食策略变化相关的古人类化石记录的进化创新，这些变化对陆地资源的变化具有重要意义。
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 C4grasses and C3vegetation 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 C3forests and C4grasslands, and that vegetation exhibits both long-term (secular) trends and orbital-scale variations. The contribution of C3plants was lower than estimates based on low-resolution carbon isotope data from paleosol carbonates and organic matter in the basin. C3plants averaged ~53% of the vegetation during the late Pliocene, from ~3.3 to ~3.04 Ma, after which time δ13Cwaxindicates more open vegetation and ~41% C3plants. This transition may have been driven by changes in basin geomorphology, but also possibly occurred as part of larger-scale drying and expansion of C4vegetation in East Africa. In addition to this secular change, we observe high amplitude variability in the δ13Cwaxrecord including oscillations between ~80 and ~0% C3plants. These vegetation changes are correlated with changes in precipitation inferred from δ2Hwaxand 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.
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DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
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影响因子：
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DOI：
10.1016/j.palaeo.2020.110190
发表时间：
2021
期刊：
Palaeoecology
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Cohen, Andrew S.
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影响因子：
2.8
作者：
A. Hill;S. Ward
通讯作者：
S. Ward
撤回：Baringo-Tugen-Barsemoi (HSPDP-BTB13-1A) 岩心的年代地层学 – 40Ar/39Ar 测年、磁性地层学、地层学、层序地层学和贝叶斯年龄建模
DOI：
10.1016/j.palaeo.2019.109258
发表时间：
2019
期刊：
Palaeogeography, Palaeoclimatology, Palaeoecology
影响因子：
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作者：
A. Deino;M. Sier;D. Garello;C. B. Keller;J. Kingston;J. J. Scott;G. Dupont‐Nivet;A. Cohen
通讯作者：
A. Cohen