| 东南极普里兹湾陆隆区脊状沉积体的结构和形成过程 |
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| 引用本文：沈中延,杨春国,高金耀,纪飞.2015.东南极普里兹湾陆隆区脊状沉积体的结构和形成过程[J].地球学报,36(6):709-717. |
| DOI：10.3975/cagsb.2015.06.03 |
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| 基金项目:国家自然科学基金青年基金(编号: 41306201); 国家海洋局“南北极环境综合考察与评估专项”之“南极周边海洋地球物理考察”(编号: CHINARE2014-01-03; CHINARE2015-01-03)和“南极环境综合分析与评价”项目(编号: CHINARE2014-04-01; CHINARE2015-04-01) |
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| 中文摘要:东南极普里兹湾陆隆区发育数个近垂直陆缘的脊状沉积体, 这些沉积体记录了区域冰川活动和底流变化的历史。本文主要利用多道地震资料和水深资料对这些脊状沉积体的平面展布、走向上的结构差异进行了研究, 在此基础上讨论了不同脊状沉积体的形成过程。结果表明研究区内脊状沉积体有两种不同结构类型: 西部Wild峡谷两侧不对称发育的浊流堤岸沉积形成两个平行峡谷的脊状沉积体; 东部数个脊状沉积体的形成与其下长期存在的浊流活动引起的穿时沉积间断面有关。不同峡谷的浊流活动起始时代不一, 西部的Wild峡谷起始时代和陆隆区冰海沉积起始时代(P1)一致; 东部Wilkins峡谷以及Murray峡谷从后期的P3(约26.1 Ma)开始, 代表普里兹湾地区的一次冰川极盛事件。研究区所有峡谷及其浊流活动均随时间向海扩展, 造成相应的脊状沉积体向海扩展。在脊状沉积体外缘区域, 浊流输送而来的细粒沉积物在向西的底流作用下形成大型深海沉积物波。 |
| 中文关键词:东南极 普里兹湾 脊状沉积体 浊流 等深流 沉积物波 |
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| Structure and Development Processes of the Sediment Ridges on the Continental Rise off the Prydz Bay Margin, East Antarctica |
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| Abstract:Several sediment ridges (SRs) are located on the continental rise off the Prydz Bay margin, East Antarctica. These SRs recorded the history of the regional glacial movements and bottom current activities. Multichannel seismic reflection data in this region have been interpreted together with bathymetry data for the planar distribution, cross-section structures along strike, and the formation and development processes of the SRs. On such a basis, two different groups of the SRs have been identified. The first group includes two SRs which were asymmetric levees on both sides of the Wild Canyon in the western part of the study area. The second group includes SRs in the eastern part of the study area whose formation and development were closely related to the local, diachronous hiatuses generated by the turbidity flow. The onset time of the turbidity activities in different canyons is not concurrent. For Wild Canyon in the west, the onset time is P1, which is the base of the glaciomarine deposit on the continental rise, while for Wilkins and Murray Canyon in the east, it began at a later time P3 (~26.1 Ma), which represents an expansion of the glaciers in Prydz Bay area. All the canyons and the turbidity currents within them both extended seaward with time and so did the consequent SRs. In the areas north of the seaward edge of the SRs, large deep sea sediment waves consisting of fine-grained sediments supplied mainly by down-slope turbidity currents were generated under westward-flowing bottom currents. |
| keywords:East Antarctica Prydz Bay sediment ridge turbidity current contour current sediment wave |
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