阿拉伯海北部莫克兰增生楔天然气水合物浅表层识别标志

    Shallow and submarine identifications of gas hydrate in the Makran accretionary prism, northern Arabian Sea

    • 摘要: 阿拉伯海北部的莫克兰增生楔是阿拉伯板块以低速、低角度俯冲到欧亚板块之下形成的主动陆缘构造,蕴藏着丰富的天然气水合物资源。依据2019年中国在莫克兰增生楔海域采集的高分辨率多道地震资料、浅地层剖面及多波束测深数据,并结合以往的调查成果,探讨莫克兰海域天然气水合物存在的浅表层识别标志。地震识别标志主要有似海底反射层(BSR)和振幅空白带2种标志,地形地貌标志包括海底麻坑、海底滑塌、丘状体、泥火山、冷泉系统等,水体标志主要为羽状流。在水深1000m和2900m的站位已分别钻获水合物样品。莫克兰增生楔丰富的水合物识别标志可能与低速、低角度的俯冲地质背景有关,使该区水合物存在指示兼具主动大陆边缘和被动大陆边缘的特征。综合研究区的异常标志分布特征,推测增生楔中部和西部的背斜脊及其附近区域是天然气水合物远景区。

       

      Abstract: The Makran accretionary prism located in the northern Arabian Sea is formed by the subduction of the Arabian plate beneath the Eurasian plate in a northerly direction at low speed and low angle,and there are abundant gas hydrate resources in the accretionary prism. Based on the high-resolution multi-channel seismic data,sub-bottom profile and multi-beam echo sounding data acquired by China in 2019, combined with the former investigation results,this paper discusses the shallow and submarine identifications of gas hydrate in the Makran accretionary prism. The seismic identifications mainly include bottom simulating reflector(BSR)and acoustic blank zone. The topographic and geomorphic signs include submarine pockmark,submarine slump,mound,mud volcano and cold seeps system. The water body signs mainly is flare. Gas hydrate samples have been drilled at the stations with water depth of 1000 m and 2900 m respectively. The abundant hydrate identifications of Makran accretionary prism may be related to the low velocity and low angle subduction geological background,which makes the hydrate identifications in this area show the characteristics of active continental and passive continental margins. Based on the distribution characteristics of identifications in the study area,the anticlinal ridges and theiradjacent areas in the central and western parts of accretionary prism are the gas hydrates prospective areas.

       

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