Late Pleistocene and Holocene aeolian sedimentation in Gonghe Basin, northeastern Qinghai-Tibetan Plateau: Variability, processes, and climatic implications
Late Pleistocene and Holocene aeolian sedimentation in Gonghe Basin, northeastern Qinghai-Tibetan Plateau: Variability, processes, and climatic implications
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青藏高原东北部共和盆地晚更新世和全新世风沙沉积：变化、过程和气候影响
DOI：
10.1016/j.quascirev.2015.11.010
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发表时间：
2016-01
影响因子：
4
通讯作者：
Chen, Fahu
中科院分区：
文献类型：
--
作者：
Song, Lei;Li, Hao;Li, Fengshan;Chen, Fahu
尽管干旱地区风沙沉积的地层序列长期以来被认为提供了有关过去环境的信息，但它们所反映的环境过程的确切性质仍然不清楚。本文报道了青藏高原东北部共和盆地8个露头剖面的详细调查结果。沉积物粒度和化学成分的测量表明，这些沉积物主要是风成成因的，由互层、分选良好的砂、粉砂、黄土和/或古土壤组成，但它们的赋存状态因地点而异。古沙丘沙主要分布在现今稳定或半稳定的沙丘区或其附近，而黄土则分布在下风向边缘地区。这种盆地尺度分异格局主要受控于盆地内部先期沉积模式造成的沉积物供给的空间变异性。结合已发表的光致发光年龄，用24个新的光致发光年龄来阐明风沙活动的历史及其与气候变化的关系。过去的沙丘活动与顺风向黄土沉积之间没有明显的关系。粉砂沉积可能发生在晚更新世多风、干燥和寒冷的气候阶段。然而，单靠气候因素不能解释粉砂淤积的发生。这是因为在河流切割之前，粉砂的沉积总是先于河流沉积，从而表明与河流沉积过程相关的“激活”沉积物供应的重要性。分选良好的砂岩沉积不仅发生在晚更新世，而且还发生在早至全新世中期。植被条件对沙粒的移动和沉积起着重要的作用，它要么受晚更新世期间出现的水分亏缺间隔控制，要么受局部尺度上降水与蒸散平衡的变化所控制。共和盆地耿嘎海风沙活动的独立证据也表明了植被对沙粒运动的影响。这里，早、中全新世盆地的风沙沉积表明，尽管湖泊沉积记录到的区域降水量增加，但夏季较高的日照引起的高蒸发导致了低水平的有效水分。相比之下，晚全新世古土壤代表了高水平的有效水分，它们的形成不一定需要增加区域降雨量。总体而言，我们的结果表明，风沙活动与区域气候变化之间的关系是复杂的，沙粒堆积并不代表与气候变化相关的地表过程的一致作用。
Although stratigraphic sequences of aeolian deposits in dryland areas have long been recognized as providing information about past environments, the exact nature of the environmental processes they reflect remains unclear. Here, we report the results of a detailed investigation of eight outcrop sections in the Gonghe Basin, northeastern Qinghai-Tibetan Plateau. Measurements of sediment grain-size and chemical composition indicate that the deposits are primarily of aeolian origin, consisting of interbedded, well-sorted sand, silty sand, loess and/or palaeosol; however, their occurrence varies from site to site. Fossil dune sands mainly occur in or close to the currently stabilized or semi-stabilized dune fields, whereas loess is distributed along the downwind marginal areas. This pattern of basin-scale differentiation was controlled mainly by spatial variability of sediment supply due to the antecedent sedimentary patterns within the basin. Together with previously-published optically stimulated luminescence (OSL) ages, 24 new OSL dates are used to elucidate the history of aeolian activity and its relationship to climatic changes. There is no apparent relationship between past dune activity and downwind loess deposits. Deposition of silty sand probably occurred during past phases of windy, dry and cold climate in the Late Pleistocene. However, climatic factors alone cannot explain the occurrence of silty sand deposition. This is because the deposition of silty sand was always preceded by episodes of fluvial deposition prior to river incision, thereby indicating the importance of an ‘activated’ sediment supply associated with fluvial processes. Deposition of well-sorted sand occurred episodically, not only during the Late Pleistocene, but also during the early- to mid-Holocene. Vegetation conditions, controlled either by the occurrence of intervals of moisture deficit during the Late Pleistocene or by changes in the balance between precipitation and evapotranspiration at a local scale, played an important role in sand mobility and deposition. The effect of vegetation on sand mobility is also suggested by independent evidence of aeolian activity from Genggahai Lake in the Gonghe Basin. Here, the deposition of aeolian sand in the basin during the early- to mid-Holocene indicates a low level of effective moisture caused by high evaporation induced by higher summer insolation, despite the coeval increased regional precipitation recorded by lacustrine sediments. In contrast, late Holocene palaeosols represent a high level of effective moisture, and their formation did not necessarily require increased regional precipitation. Overall, our results suggest that the relationship between aeolian activity and regional climate change is complex, and that sand accumulations do not represent the consistent action of surface processes that are related to climatic changes.
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华北沙丘和黄土高原晚第四纪地表过程对气候变化的响应
影响因子：
3.3
作者：
Huayu Lu;Joseph A. Mason;Thomas Stevens;Yali Zhou;Shuangwen Yi1;Xiaodong Miao
通讯作者：
Xiaodong Miao
评估中亚伊犁盆地黄土中石英颗粒定年的 OSL-SAR 协议
影响因子：
2.7
作者：
Mazzocco Jeaneth;Li Xinxin;Shi Zhengtao;Fang Xiaomin
通讯作者：
Fang Xiaomin
亚洲夏季季风降水时空格局对全新世日照变化的响应：模型数据综合
影响因子：
4
作者：
Wonsun Park;Mojib Latif;Vyacheslav Khon;Xiaojian Zhang
通讯作者：
Xiaojian Zhang
DOI：
10.1016/j.palaeo.2009.12.005
发表时间：
2010-02
期刊：
Palaeogeography, Palaeoclimatology, Palaeoecology
影响因子：
--
作者：
M. Qiang;Fahu Chen;Zhen-Ting Wang;Guang-ming Niu;Lei Song
通讯作者：
M. Qiang;Fahu Chen;Zhen-Ting Wang;Guang-ming Niu;Lei Song
DOI：
--
发表时间：
2004
期刊：
Progress in geography
影响因子：
--
作者：
L. Qi
通讯作者：
L. Qi