| 天山北麓晚新生代沉积及其新构造 与古环境指示意义 * |
| |
| 引用本文： | 孙继敏,朱日祥.天山北麓晚新生代沉积及其新构造 与古环境指示意义 *[J].第四纪研究,2006,26(1):14-19. |
| |
| 作者姓名： | 孙继敏 朱日祥 |
| |
| 作者单位： | 中国科学院地质与地球物理研究所,北京,100029 |
| |
| 基金项目： | 国家重点基础研究发展计划(973计划) |
| |
| 摘 要： | 天山山脉隶属中亚造山带,晚新生代时期印度板块向亚洲板块俯冲的构造效应同样影响到天山地区,使这一晚古生代形成的造山带重新复活。天山南北两侧的晚第三纪和第四纪时期的地层正是对印度板块-亚洲板块碰撞带的响应,发生构造变形,形成了一系列逆冲断层和褶皱,指示这一区域的地壳在晚新生代变短和加厚。文章对天山北缘晚中新世以来的沉积进行了详细的磁性地层学和沉积学研究,结果表明:在研究的独山子背斜地区,磨拉石沉积最早出现于约7百万年前,说明天山山脉自7百万年前开始有一次构造隆升,研究区内7.00~2.58Ma间的巨厚砾石沉积主要是构造抬升的结果。而早更新世的西域砾岩沉积在很大程度上与第四纪时期全球冰期的来临,特别是北半球开始发育大规模冰川作用有关,因此西域砾岩应当是在第四纪冰川作用(气候变冷)及新构造运动共同作用下的产物。
|
| 关 键 词： | 天山山脉 晚新生代沉积 新构造运动 西域砾岩 |
| 文章编号： | 1001-7410（2006）01-14-06 |
| 收稿时间： | 2005-10-24 |
| 修稿时间： | 2005-11-17 |
CENOZOIC DEPOSITS IN THE NORTHERN TIANSHAN MOUNTAINS AND ITS IMPLICATIONS FOR NEOTECTONICS AND ENVIRONMENTAL CHANGES |
| |
| Sun Jimin,Zhu Rixiang.CENOZOIC DEPOSITS IN THE NORTHERN TIANSHAN MOUNTAINS AND ITS IMPLICATIONS FOR NEOTECTONICS AND ENVIRONMENTAL CHANGES[J].Quaternary Sciences,2006,26(1):14-19. |
| |
| Authors: | Sun Jimin Zhu Rixiang |
| |
| Institution: | Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 |
| |
| Abstract: | The exceptional topographic relief in High Asia provides an opportunity to quantify the uplift history related to the India-Asia collision,as well as the effects of the high topography on global circulation patterns.The Tianshan Mountains just lie in the actively deforming part of the India-Asia collision zone.The thrust faulting and folding of the Neogene and Quaternary sediments in the piedmont depression zones of the Tianshan Mountains,form linear,roughly east-west anticlines at the northern and southern borders of the orogenic belts,indicating crustal shortening and thickening in the Late Cenozoic time.Such thick Cenozoic terrestrial sequences were shed into foreland basins,holding great potential for understanding the relationships between mountain building,rock denudation,sediment deposition,and climate.To better understand the uplift history of the Tianshan Mountains,we undertook a paleomagnetic study of ca.1200m thick piedmont sediments,from which we collected 1400 specimens in the northern foot of the mountains.Our paleomagnetic investigations of the Late Miocene-Pleistocene terrestrial sequences provide the first detailed and long-term chronological control for the thick molasse deposits in the studied region,thus providing a solid base for discussing the uplift history since the Late Miocene.The magnetostratigraphic results indicate that an episode of uplift of the Tianshan Mountains occurred around ca.7Ma ago marked by the occurrence of the molasse deposits,and the uplift possibly lasted to ca.2.58Ma.The uplift between 7Ma and 2.58Ma in the studied region was mainly in response to the tectonic uplift.However,the prominent Early Pleistocene Xiyu Formation,which consists of conglomerates,is at least partially associated with the mountain glaciations as a response to the onset ice sheet in the Northern Hemisphere since 2.58Ma.Additionally,the existence of the angular unconformity between the Xiyu Formation and its overlying Middle Pleistocene strata should indicate tectonic movement around the end of the Early Pleistocene.In this sense,the accumulation of the Early Pleistocene Xiyu Formation was mostly controlled by both climatic cooling and tectonics. |
| |
| Keywords: | Tianshan Mountains Cenozoic deposits neotectonics Xiyu Formation |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《第四纪研究》浏览原始摘要信息 |
| 点击此处可从《第四纪研究》下载免费的PDF全文 |
|
