| 库车褶皱-冲断带拜城凹陷盐构造特征与成因 |
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| 引用本文： | 唐鹏程,李世琴,雷刚林,黄少英.库车褶皱-冲断带拜城凹陷盐构造特征与成因[J].地球科学,2012,37(1):69-76. |
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| 作者姓名： | 唐鹏程 李世琴 雷刚林 黄少英 |
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| 作者单位： | 1.浙江大学地球科学系，浙江杭州 310027 |
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| 基金项目： | 国家科技重大专项2009ZX05009-001 |
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| 摘 要： | 关于沉积差异负载对褶皱-冲断带中塑性盐岩变形的影响仍然不清楚，库车褶皱-冲断带拜城凹陷受到的构造挤压变形微弱，凹陷中沉积了巨厚的盐上覆层，是研究沉积差异负载如何影响塑性盐岩变形的天然实验室.根据野外地表调查结果、钻井资料和二维地震剖面，约束库车褶皱-冲断带拜城凹陷盐构造特征，并探讨盐构造成因机制.盐顶构造图揭示拜城凹陷盐上覆层发育东、西2个沉积中心，东沉积中心位于拜城县附近，西沉积中心位于BZ1井南侧，二者之间(大宛齐乡附近)形成大宛齐盐枕和拜城凹陷鞍部.钻井资料和地震剖面显示:(1)东、西沉积中心下伏盐岩流动减薄，二者之间盐岩聚集加厚；(2)大宛齐盐枕核部盐岩聚集发生于上新世晚期-现今；(3)上新世末期-现今，拜城凹陷鞍部下伏盐岩聚集加厚，盐岩厚度往东、西沉积中心逐渐减薄，形成东西向背形构造.基于盐构造特征和前人研究成果，提出库车褶皱-冲断带拜城凹陷盐构造相关的盐岩流动变形模型，认为沉积差异负载在库车褶皱-冲断带盐岩变形中发挥着重要作用:(1)在挤压应力和沉积差异负载作用下，以东、西沉积中心为圆心，盐岩向四周放射状流动；(2)盐岩变形以沿挤压方向(N-S)流动为主，但剖面间(E-W)流动也很明显.
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| 关 键 词： | 盐构造 沉积中心 沉积差异负载 盐岩流动 拜城凹陷 库车褶皱-冲断带 构造地质 沉积 |
| 收稿时间： | 2011-02-28 |
Characteristics and Formation of Salt Structures in Baicheng Sag,Kuqa Fold-and-Thrust Belt |
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| Abstract: | The role of differential sedimentary loading in deformation of viscous rock salt in contractional setting is unclear. Combined with field observation, well and seismic data, salt structures in Baicheng sag, Kuqa fold-and-thrust belt were constrained, and their formation mechanisms were investigated. The structural map of top salt shows that two depocenters were developed in Baicheng sag, eastern depocenter near Baicheng County and western depocenter to the south of well BZ1, respectively. Dawanqi salt pillow and saddle of Baicheng sag were developed between two depocenters. Seismic and well data reveals that: (1) the salt layer below two depocenters is very thin, while thick salt layer has accumulated between two depocenters; (2) Dawanqi salt pillow formed from the Late Pliocene to present; (3) the saddle of Baicheng sag, which is an antiform structure in E-W trend, formed from the end of Late Pliocene to present. Based on our investigations and previous studies, we propose a model showing salt flow related to salt structures in Baicheng sag, Kuqa fold-and-thrust belt, and it suggests that differential sedimentary loading plays an important role in Kuqa fold-and-thrust belt: (1) under bulk shortening and differential sedimentary loading, salt flew out of depocenter in three-dimensional; (2) salt flew dominantly along the direction of contraction (N-S) and also obviously along strike (E-W). |
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