| 北京温榆河的成因 |
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| 引用本文： | 蔡向民,黄,淇,张,磊,白凌燕.北京温榆河的成因[J].中国地质,2014,41(5):1515-1521. |
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| 作者姓名： | 蔡向民 黄 淇 张 磊 白凌燕 |
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| 作者单位： | 北京市地质调查研究院,北京,102206 |
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| 基金项目： | 北京市国土资源局“北京平原区活动断裂监测专项地质调查项目”(京国土环【2009】308号文)资助。 |
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| 摘 要： | 温榆河是北京平原北部一条重要的河流。温榆河两岸地质背景复杂,地质灾害严重。地质调查表明,温榆河的形成与演化与南口—孙河断裂密切相关,受该断裂的严格控制。经钻探发现,温榆河南口至百善一带最早的新生代沉积物产生于早更新世。说明温榆河的形成时间应是早更新世早期。温榆河在温榆河河谷内不断迁移,受断裂控制河床的迁移被限制在南口—孙河断裂的下降盘一侧。在南口至马池口一带因南口—孙河断裂上盘下降,形成了深达数百米的凹陷,沉积了巨厚的松散沉积物。在凹陷范围内长期存在一个湖泊,温榆河是该湖泊的泄水通道。在昌平区冷泉、辛庄、高里掌和辛力屯一带的广大地区,发现地下几米处见有含螺贝壳的泥炭层,似层状多层、延伸连续,厚度稳定可达数米。经测定,泥炭层底部14C年龄(9930±150)a,顶部泥炭层14C年龄约3 ka。说明该湖泊10 ka前湖水较浅,适合水生植物生长,随后湖水逐渐消退。湖水的完全消失距今不到3 ka的时间。说明温榆河的形成时代虽然很久远,但是河道不断变迁,今天温榆河的面貌还是很年轻的。
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| 关 键 词： | 温榆河 河流成因 活动断裂 |
The origin of the Wenyu River in Beijing |
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| CAI Xiang-min,HUANG Qi,ZHANG Lei,BAI Ling-yan.The origin of the Wenyu River in Beijing[J].Chinese Geology,2014,41(5):1515-1521. |
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| Authors: | CAI Xiang-min HUANG Qi ZHANG Lei BAI Ling-yan |
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| Institution: | Beijing Institute of Geological Survey, Beijing 102206, China |
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| Abstract: | Abstract: The Wenyu River is an important river in northern Beijing plain. The geological background on both sides of the Wenyu River is complex and characterized by serious geological disasters. Geological survey shows that the formation and evolution of Wenyu River were closely related to the Nankou - Sun River fault and strictly controlled by the fault. Drilling shows that the earliest Cenozoic sediments along the Nankou-Baishan section of the Wenyu River were formed in the early Pleistocene, suggesting that the Wenyu River was formed at the early stage of early Pleistocene. The Wenyu River continuously migrated in the Wenyu River Valley, but was confined on the downthrow side of the Nankou-Sun River fault due to the migration of the fracture-controlled bed. The hanging side from Nankou to Machikou formed a depression several hundred meters deep due to subsidence of the hanging wall of the Nankou - Sun River fault, and thick loose sediments were deposited. The Wenyu River is the drainage channel of the long-existent lake in the depression. In the vast area of Cold Spring, Xinzhuang, Gaolizhang and Xinlitun in Changping District, there exists a peat layer containing snail shells a few meters below the surface, which exhibits stratoid and multilayer forms and stably extends for several meters. Analytical results show that the peat layer at the bottom of the 14C is 9930 ± 150 years old whereas the top peat layer 14C is about 3 ka. These data suggest that the lake was shallow and suitable for the growth of aquatic plants ten thousand years ago, and then the lake water gradually diminished. The lake disappeared only a few thousand years ago, which suggests that, although the Wenyu River was formed very long ago, its appearance remains young due to the continuous changes of the river course. |
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| Keywords: | Wenyu River origin of the river active fault |
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