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浊积流

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浊积流(英语:turbidity current)是一种富含悬浮固体颗粒的高密度水流,其密度大于周围海水,在重力驱动下顺坡向下流动,多发生于大陆边缘地区,常受地震、滑坡、风浪等因素触发,是将陆源物质由浅海输送到深海的重要机制,可在大陆边缘或洋盆区形成浊流沉积。[1][2]

在最典型的海洋浊积流情况下,位于倾斜地面上的载有沉积物的水将向山下流动,因为它们的密度高于邻近水域。浊积流背后的驱动力是重力作用,来于暂时悬浮在流体中的沉积物。这些半悬浮固体使含沉积物的水的平均密度大于周围水的平均密度[3]。当这样的水流流动时,它们通常会产生“滚雪球效应”,因为它们会搅动它们流过的地面,并聚集更多的沉积颗粒在它们的水流中。它们流过的地面会被冲刷和侵蚀[4]。一旦浊积流流到达深海平原(主要洋底)较平坦区域的较平静的水域,携带的颗粒就会从水中沉淀出来。浊积流的沉积物称为浊积岩[5]

参考文献

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  1. ^ Turbidity currents' are not just currents, but involve movement of the seafloor itself". EurekAlert!. Monterey Bay Aquarium Research Institute. 5 October 2018. Retrieved 8 October 2018
  2. ^ 朱筱敏. 层序地层学. 石油大学出版社. 2000. 
  3. ^ Sanders, J.E. 1965 Primary sedimentary structures formed by turbidity currents and related resedimentation mechanisms. In: Primary Sedimentary Structures and Their Hydro-Dynamic Interpretation – a Symposium Middleton, G. V.), SEPM Spec. Publishers , 12, 192–219.
  4. ^ Wells, Mathew G.; Dorrell, Robert M. (2021-01-05). "Turbulence Processes Within Turbidity Currents". Annual Review of Fluid Mechanics. 53 (1): 59–83. doi:10.1146/annurev-fluid-010719-060309. ISSN 0066-4189
  5. ^ Meiburg, E. & Kneller, B. 2010, "Turbidity currents and their deposits", Annual Review of Fluid Mechanics, vol. 42, pp. 135–156