海山对深水底流沉积过程及演化的影响研究进展

Research progress in seamount influence on depositional processes and evolution of deep-water bottom currents

  • 摘要: 海山是广泛分布于深水区的一种构造地貌类型,底流则是一种长期存在于深水区的沉积动力,故二者之间将会不可避免地发生相互作用,对深水沉积过程及其演化具有不可忽略的控制作用。通过归纳总结全球海山区底流沉积过程研究成果,指出在海山的直接或间接作用下,深水底流沉积动力受到影响,流动路径发生改变,产生次级底流沉积动力,同时也可影响生物群落分布,进而导致海山区沉积地貌及岩相表现出独特的平面展布特征。随着海山区底流沉积动力和沉积地貌背景的垂向演变,不同时期底流沉积过程及其响应也有所差异。因此,海山区底流沉积动力复杂且具特殊性,造就了不同于开阔陆坡背景下的底流沉积地貌和岩相特征及时空分布规律,其对深海盆地构造和古海洋演化的指示意义也与开阔陆坡底流沉积体系有所不同。目前有关海山与底流沉积过程之间的耦合关系研究程度还相对较低,极大地限制着深水资源勘探和地质灾害预测,这一问题有必要在未来深水沉积学研究中给予重点关注。

     

    Abstract: Seamount is a kind of tectonic geomorphological features widely distributed in the deep sea around the world, where bottom currents persistently exist, thus the interactions between seamounts and bottom currents are very common and will bring about non-negligible influence on deep-water sedimentation and their evolution. This study summarized the global researches on the deep water sedimentation by bottom currents around seamounts, suggesting that deep-water bottom-current hydrodynamics would change under the direct or indirect influence of seamounts, including the changing in flow paths, generation of secondary bottom currents, and variation in ecosystems. Consequently, deep-water sedimentary morphologies and lithofacies would display special distribution patterns. With the evolution of bottom-current hydrodynamics and sedimentary morphologies, deep water sedimentation processes and associated responses would change as well. In summary, bottom currents are complex and special around seamounts, resulting in sedimentary morphologies and lithofacies features as well as distribution patterns differing from those on the open slope. Thus, the sedimentary morphologies and lithofacies formed under bottom currents around seamounts have very particular implications for basin structures and palaeoceanography evolution. However, there is still lack of study concerning the coupling relationship between seamounts and deep water sedimentation processes, greatly limiting deep-sea resource exploration and geo-hazard study, thus more attention is required to be paid to the relationships in the future research of deep-water sedimentology.

     

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