| 海底麻坑的特征、分类与成因机制 |
| |
| 引用本文： | 沈奥,孙启良,蔡砥柱,邢子浩.海底麻坑的特征、分类与成因机制[J].地质科技通报,2023,42(1):204-217. |
| |
| 作者姓名： | 沈奥 孙启良 蔡砥柱 邢子浩 |
| |
| 作者单位： | 1.中国地质大学(武汉)海洋地质资源湖北省重点实验室, 武汉 430074 |
| |
| 基金项目： | 中国地质调查局地质调查项目DD20211554 |
| |
| 摘 要： | 海底麻坑是由超压流体溢出海底时侵蚀海底沉积物所形成的一种负地貌, 其广泛分布于各种水下构造环境(如大陆边缘盆地和增生楔等)。综合近年有关海底麻坑的研究成果, 依据麻坑形状、直径、长宽比、空间分布以及垂向充填方式等特征, 对其类型进行了系统划分, 详细介绍了麻坑形成的主要条件及影响因素(如底辟、断层等), 深入阐释了麻坑的成因机制。麻坑形成过程中, 地层中的局部异常流体压力(超压)是最为关键的条件和驱动因素。根据地层中超压形成和释放过程的快慢, 可以将麻坑的成因机制划分为渐进型、突发型和混合型3类。渐进型麻坑形成过程中, 地层超压的形成和释放的过程较为缓慢; 突发型麻坑形成过程中地层超压形成和释放的过程较快; 混合型麻坑的形成过程介于二者之间。鉴于麻坑在形成过程中受到海水和下伏地层等多种因素的共同影响, 未来十分有必要对海底深部地层中“超压形成-流体聚集-垂向运移至海底表面并逸散-形成麻坑”的整个动态过程展开物理和数值模拟研究, 进一步建立海底麻坑形成模式。
|
| 关 键 词： | 海底麻坑 分类 影响因素 成因机制 |
| 收稿时间： | 2021-06-20 |
Characteristics,classification and genetic mechanism of pockmarks |
| |
| Affiliation: | 1.Hubei Key Laboratory of Marine Geological Resources, China University of Geosciences(Wuhan), Wuhan 430074, China2.Haikou Marine Geological Survey Center, China Geological Survey, Haikou 570100, China |
| |
| Abstract: | Pockmarks are a kind of negative geomorphology formed by overpressure fluid spilling from the seabed. They are widely distributed in various underwater tectonic environments (such as continental margin basins and accretion wedges). Based on the recent research progress and achievements of pockmarks, this paper systematically divides the types of pockmarks according to their shapes, diameters, length width ratios, distribution characteristics and vertical filling modes. Moreover, this paper detailed introduces the main conditions and influence factors (such as diapir and fault)and deeply analyzes the genetic mechanisms of pockmarks. The local abnormal fluid pressure (overpressure) is the key factor to trigger the formation of pockmarks. According to the formation and leakage speed of overpressure during pockmark formation, the genetic mechanisms of pockmarks can bedivided into progressive, sudden and transitional three types. In the progressive formation model, both the formation and leakage processes of overpressure are slow. Whilst in the sudden formation model, the formation and leakage processes of overpressure are fast. For the transitional model, the formation and leakage processes of overpressure are faster than those of the progressive model but slower than those of the sudden model. The formation of pockmarks is affected by many factors, such as seawater and underlying strata. The physical and numerical simulation of dynamic overpressure formation and vertical migration to the seabed may be the future study directions of pockmarks. |
| |
| Keywords: | |
|
| 点击此处可从《地质科技通报》浏览原始摘要信息 |
|
点击此处可从《地质科技通报》下载全文 |
|
