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[第7篇SCI]滹沱河上游忻定古湖的决口及构造对横向冲沟形成的意义
热度 2 baul 2013-10-27 07:30
Tectonic controls for transverse drainage and timing of the Xin-Ding paleolake breach in the upper reach of the Hutuo River, north China Junjie Ren a, b , Shimin Zhang a , Andrew J. Meigs b ,Robert S. Yeats b ,Rui Ding a ,Xiaoming Shen a a Key Laboratory of Crustal Dynamics, Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China b College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA Highlights •We reconstruct fluvial terrace sequence and long-term drainage evolution in the upper reach of the Hutuo river system. •The creation of the transverse drainage and breach of the Xin-Ding paleolake occurred between ~ 600 and ~ 130 ka. •The mechanism for the creation of transverse drainage is river capture because of localized differential tectonic uplift and associated tilting. Abstract The upper reach of the Hutuo River flows along the Xin-Ding basin and cuts a transverse drainage through the Xizhou Mountain and the Taihang Range into the North China Plain. Previous studies showed that the Xin-Ding basin was occupied by a lake during the early-middle Pleistocene. However, the timing of the paleolake breach and the mechanism for the creation of the transverse drainage are unknown. We constructed the fluvial terrace sequence in the upper reach of the Hutuo drainage combined with thermoluminescence (TL) and optically stimulated luminescence (OSL) dating, as well as the timescale of the overlying loess–paleosol sequence. Our results reveal that (1) five terraces (T5-T1) developed along the upper reach of the Hutuo River, amongst which terraces T4-T1 were formed synchronously at ~ 600, ~ 120-130, ~ 20-26 and ~ 6-7 ka, respectively; (2) the creation of the transverse drainage and breach of the Xin-Ding paleolake occurred between ~ 600 and ~ 130 ka; and (3) the mechanism for the creation of the transverse drainage is via river piracy of paleostreams on both sides of the drainage divide. Localized differential uplift and associated tilting of the Xizhou Mountain block during the middle Pleistocene result in the formation of the transverse drainage and breach of the Xin-Ding paleolake. Geomorphology Volume 206 , 1 February 2014, Pages 452–467 http://www.sciencedirect.com/science/article/pii/S0169555X13005321 Junjie Ren_Geomorphology2014.pdf
个人分类: 研究论文|5162 次阅读|6 个评论
川滇块体东北缘晚第四纪区域气候-地貌分析及其构造地貌年代学意义
cgh 2010-8-24 17:54
川滇块体东北缘晚第四纪区域气候-地貌分析及其构造地貌年代学意义 陈桂华,徐锡伟,袁仁茂,闻学泽,郑荣章 摘要 :地貌年代是新构造特别是活动构造定量研究的瓶颈问题。通过对川滇块体北东边界构造带所在的区域气候变化过程和地貌研究成果的综合分析,利用众多的年代学数据,从区域尺度对地貌的年代、形态和物质组成等特征对比分析,探讨了该区冰川地貌、河流阶地和冲洪积扇的演化特征,揭示了区域气候变化与区域性地貌演化存在的内在对应关系。气候变化产生的气温、湿度、降水量等变化控制了该区冰川地貌和流水地貌的演化。区域内冰川地貌主要是末次冰期的产物,对应于末次冰期两个冰阶,河流作用在7~10ka和1~5ka两个阶段改造末次冰期堆积地貌形成相应的侵蚀地貌。主要河流阶地发育对应于降水量剧烈变化的气候过程,其中形成三级阶地面的流水下切作用最强,随后堆积的深厚物质是二级阶地的主体,并一直没有被后期流水下切作用蚀穿,与气候变化的强度等特点对应。区内冲洪积扇主要有3个堆积时期,即3~5ka,7~10ka和20~25ka,主要发育在气候变化最剧烈的时期,大量的碎屑物形成并短距离搬运堆积。将区域分析综合的结果应运到康定南团结乡附近的地貌分析,可以很好的理解该区的地貌演化,用侵蚀改造的地貌演化结论否认了以前的堆积地貌认识,理清了地貌发育的年龄序列。综合分析与应用的结果表明,区域气候-地貌-构造系统研究对于活动构造年代学具有非常重要的意义。 pdf全文下载
个人分类: 地震地质|4680 次阅读|0 个评论

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