Holocene aeolian activity in the Headwater Region of the Yellow River, Northeast Tibet Plateau, China: A first approach by using OSL-dating
Holocene aeolian activity in the Headwater Region of the Yellow River, Northeast Tibet Plateau, China: A first approach by using OSL-dating
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DOI：
10.1016/j.catena.2016.09.014
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发表时间：
2017-02
期刊：
影响因子：
6.2
通讯作者：
Guangyin Hu;Lupeng Yu;Z. Dong;H. Jin;D. Luo;Yixuan Wang;Z. Lai
中科院分区：
文献类型：
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作者：
Guangyin Hu;Lupeng Yu;Z. Dong;H. Jin;D. Luo;Yixuan Wang;Z. Lai
黄河源区是多石峡上游的集水区，面积29,588平方公里。青藏高原位于青藏高原东北部，海拔4000米以上，对气候变化特别敏感。世纪后期以来，青藏高原年平均气温急剧上升。由于气温上升，在过去几十年中出现了许多环境问题，包括风成荒漠化。多年冻土对草原植被的维持起着重要作用，近年来，由于多年冻土的退化，风沙化已成为青藏高原严重的环境问题。随着地温的升高，高原地区的风沙活动有可能加剧。然而，由于缺乏年代学研究，HRYR的风沙活动历史仍然未知。本文利用3个典型剖面的15个光释光年龄资料，揭示了全新世以来青藏高原风沙活动的历史。OSL年龄均为晚全新世，最大年龄为2.13 ± 0.16kaBP。相对年轻的光释光年龄和深层风成沉积物表明，全新世晚期，尤其是1 ka BP左右之后，沉积速率非常高。全新世晚期风沙活动强烈，TOC含量较低，气候较干燥。这三个断面的沉积物分选性好，粒度分布相似，表明它们具有相似的风况。根据黄河溯源侵蚀的演变历史，推测全新世早、中期，本区风沙活动较少。
The Headwater Region of the Yellow River (HRYR) is the catchment upstream of Duoshi Gorge, covering an area of 29,588 km2. The HRYR is located in the northeastern Tibet Plateau with an altitude higher than 4000 m above sea level, and is especially sensitive to climate change. Since the late 19th century, the mean annual temperature in Tibet Plateau has increased sharply. As a result of increasing air temperature, a significant number of environmental problems have occurred during the past decades, including aeolian desertification. In recent decades, aeolian desertification has become a severe environmental problem in the Tibet Plateau due to permafrost degradation, because permafrost plays an important role in maintaining the grassland vegetation. With the increase in ground temperature, the aeolian activity in the HRYR is likely to become more serious. However, the history of aeolian activity in the HRYR remains unknown due to a lack of chronological studies. In this study, 15 Optical Stimulated Luminescence (OSL) ages from three typical sections were used to reveal the history of aeolian activities in the HRYR during the Holocene. All of the OSL ages were late Holocene, and the oldest age is 2.13 ± 0.16 ka BP. The relative young OSL ages and deep aeolian sediment indicated very high sedimentation rates in the late Holocene, especially after around 1 ka BP. The intensive aeolian activity and low TOC content indicate a drier climate in the late Holocene. The well-sorted sediments and similar grain size distributions of the three sections imply their similar wind regimes. Based on the evolution history of the Yellow River's headward erosion, it is inferred that little aeolian activity occurred in this region during the early and mid-Holocene.