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| 塔里木西缘晚新生代造山过程的记录——磨拉石建造及生长地层和生长不整合 | |
| 引用本文： | 陈杰,卢演俦,丁国瑜.塔里木西缘晚新生代造山过程的记录——磨拉石建造及生长地层和生长不整合[J].第四纪研究,2001,21(6):540-550. |
| 作者姓名： | 陈杰 卢演俦 丁国瑜 |
| 作者单位： | 1. 中国地震局地质研究所新年代学开放实验室,北京,100029 2. 中国地震局分析预报中心,北京,100036 |
| 基金项目： | 国家自然科学基金项目 (批准号 :4 0 0 72 0 99，4 9894 1 74和 4 0 0 2 4 2 0 2 )资助 |
| 摘 要： | 通过对黄土高原洛川、长武剖面最近35万年来陆生蜗牛化石的高分辨率研究,揭示出喜温湿和喜冷干蜗牛种类分别存在不同的变化周期:喜温湿类蜗牛化石所揭示的东亚夏季风的变化存在明显的41 000a和23 000a周期,与地轴倾角和岁差(低纬度太阳辐射)的变化周期有关;而反映冬季风变化的喜冷干蜗牛种类则表现出不同的变化特点,其主要为0.1Ma和41 000a的周期.冬、夏季风的变化与地轴倾角41 000a周期都存在很好的相关性,但与地球轨道的岁差(19 000～23 000a)及偏心率(0.1Ma)的周期没有一致的相关关系.在轨道尺度上冬、夏季风之间不存在此消彼长的简单变化模式. |
| 关 键 词： | 塔里木西缘 晚新生代磨拉石建造 西域砾岩 生长地层 生长不整合 |
| 收稿时间： | 2001-08-29 |
| 修稿时间： | 2001年8月29日 |
RECORDS OF LATE CENOZOIC MOUNTAIN BUILDING IN WESTERN TARIM BASIN:MOLASSES,GROWTH STRATA AND GROWTH UNCONFORMITY |
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| Institution: | 1. Laboratory of Geochronology, Institute of Geology, China Seismological Bureau, Beijing 100029; 2. Center for Analysis and Prediction, China Seismological Bureau, Beijing 100036 |
| Abstract: | In two foreland basins along the north foot of Pamirs-West Kunlun Shan and the South foot of Tian Shan,very thick late Cenozoic molasses include four formations:Atushi,Xiyu,Wusu,and Gebi. The commonly assigned age of this sequence is based on lithostratigraphic correlations with few biostratigraphically constrained sections in western Tarim,resulting in an erroneous inference:it should be the synchronous deposition of the Xiyu Conglomerate around the Tarim basin,e.g.,the Xiyu Conglomerate=the Xiyu Formation=Pleistocene. The bottom of the conglomeratic Xiyu Formation is acutely diachronous. Late Cenozoic deformation of this sequence in these two foreland basins appeared as 4～6 separate fold-thrust zones. In each of such zones there are growth strata and growth unconformities. The growth strata indicate that folding and thrusting of this sequence began at 3.6Ma B.P. near Yecheng and earlier than 2.4Ma B.P. on the southern margin of Tian Shan near Kashi. There are 4～6 folding and thrusting episodes to be identified by using growth strata and growth unconformities. The relative rates of deformation,denudation,and sedimentation were not constant during each episode. |
| Keywords: | mollusk loess orbital forcing |
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