| 山西保德黄河最高阶地形成的时代 |
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| 引用本文： | 刘运明,李有利.山西保德黄河最高阶地形成的时代[J].地理与地理信息科学,2007,23(1):101-104. |
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| 作者姓名： | 刘运明 李有利 |
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| 作者单位： | 北京大学环境学院,北京,100871 |
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| 摘 要： | 野外调查发现山西保德地区存在六级阶地序列,其中第四级阶地在保德保存最为完好,而最老的第六级阶地为晚第三纪阶地。保德地区各级阶地上砾石的岩性都以灰岩为主,砂岩次之,表明晚第三纪阶地与黄河低阶地物源相同,应该是黄河阶地。在磨扇沟T6阶地上覆厚度超过51 m的红粘土层,磁性地层的研究表明,该红粘土的底部年代在6.5 Ma左右,这与保德冀家沟的研究结果吻合,说明保德地区黄河最高阶地形成的时代约在6.5 Ma左右。而黄河则可能是伴随着8.0 Ma左右青藏高原东北缘的强烈隆升而形成。
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| 关 键 词： | 山陕峡谷 河流阶地 年代 黄河 古地磁 |
| 文章编号： | 1672-0504(2007)01-0101-03 |
| 修稿时间： | 2006年9月5日 |
Formation Age of the Highest Terrace of the Yellow River in Baode Area |
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| LIU Yun-ming,LI You-li.Formation Age of the Highest Terrace of the Yellow River in Baode Area[J].Geography and Geo-Information Science,2007,23(1):101-104. |
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| Authors: | LIU Yun-ming LI You-li |
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| Abstract: | Based on detailed field investigation,six terraces in Baode area were found,and the fourth one is the most well-developed.The highest terrace that is covered by Late Tertiary red clay is the oldest one.The lithology of gravel on sixth terrace mainly is limestone,secondly is sandstone,similar with T4 which belongs to ancient Yellow River.The authors conjecture the Late Tertiary terraces belong to ancient Yellow River.Magnetostratigraphy study shows that the bottom age of Moshangou section is about 6.5 Ma.Jijiagou section which was already studied has similar result,so the formation age of the oldest terrace in Baode area is about 6.5 Ma.However,red clay and tectonics study indicate that the Yellow River around Ordos block probably came into being as the uplift of northeastern margin of Qinghai-Tibetan Plateau at about 8 Ma. |
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| Keywords: | Shanxi-Shaanxi Gorge river terrace age the Yellow River paleomagnetism |
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