Magnetostratigraphic dating of river terraces: Rapid and intermittent incision by the Yellow River of the northeastern margin of the Tibetan Plateau during the Quaternary
Magnetostratigraphic dating of river terraces: Rapid and intermittent incision by the Yellow River of the northeastern margin of the Tibetan Plateau during the Quaternary
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DOI：
10.1029/97jb00275
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发表时间：
1997-05
影响因子：
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通讯作者：
Jijun Li;X. Fang;R. Voo;Jun-Jie Zhu;C. M. Niocaill;Y. Ono;B. Pan;Wei Zhong;Jianli Wang;T. Sasaki;Yu-Tian Zhang;Jixiu Cao;Shi-Chuang Kang;Jian-Ming Wang
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文献类型：
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作者：
Jijun Li;X. Fang;R. Voo;Jun-Jie Zhu;C. M. Niocaill;Y. Ono;B. Pan;Wei Zhong;Jianli Wang;T. Sasaki;Yu-Tian Zhang;Jixiu Cao;Shi-Chuang Kang;Jian-Ming Wang
在青藏高原东北缘临夏盆地黄河和大夏河七个阶地的河积沉积物之上的黄土序列中，已发现多达23个古土壤。最古老序列中的磁性地层记录似乎相当完整，跨越了整个第四纪。它包括松山年代内的哈拉米洛和奥杜瓦伊正常极性亚年代，以及科布山和“第 54 阶段”（以前的吉尔萨）事件的证据。 Brunhes 内的年龄限制由 14C 和热释光/光受激发光测年提供。第四纪沉积物的磁性地层年代学表明阶地形成于约1.66、1.4、1.1、0.6、0.12、0.055和0.01 Ma。这些阶地可能代表了河流长期构造引起的切割中气候引起的停顿。根据阶地高度和年龄，切割率最高为 1.66 至 1.4 Ma (∼ 1 m/kyr)，从 1.4 降至 0.12 Ma (∼ 0.1 m/kyr)，并从 0.12 Ma 增加到现在 (∼ 0.75 m/kyr)。如果河流的切割仅仅归因于青藏高原的隆升，那么在大约 1.75 Ma 首次有证据表明该地区存在黄河之后，这种隆升似乎是快速且间歇性的。然而，隆起的影响不能完全与气候变化造成的切割分开。美国地球物理联盟版权所有 1997。
Up to 23 paleosols have been identified in loess sequences that overlie fluviatile sediments on seven terraces of Huang He (the Yellow River) and Daxia He in the Linxia Basin at the northeastern margin of the Tibetan Plateau. The magnetostratigraphic record in the oldest sequence appears to be fairly complete and spans the entire Quaternary. It includes evidence for the Jaramillo and Olduvai normal polarity subchrons within the Matuyama chron, as well as the Cobb Mountain and "stage 54" (formerly Gilsa) events. Age constraints within the Brunhes are provided by 14C and thermoluminescence/optical stimulated luminescence dating. The magnetostratigraphic chronology of the Quaternary sediments indicates that terraces were formed at about 1.66, 1.4, 1.1, 0.6, 0.12, 0.055, and 0.01 Ma. The terraces may represent climatically induced pauses in long-term tectonically induced incision by the rivers. On the basis of terrace heights and ages, incision rates were highest from 1.66 to 1.4 Ma (∼ 1 m/kyr), decreased from 1.4 to 0.12 Ma (∼ 0.1 m/kyr), and increased from 0.12 Ma to present (∼ 0.75 m/kyr). If river incision is attributed solely to uplift of the Tibetan Plateau, then this uplift appears to have been rapid as well as intermittent following the first evidence of the existence of Huang He in this area at about 1.75 Ma. However, the effects of uplift cannot be fully separated from incision caused by changes in climate. Copyright 1997 by the American Geophysical Union.