濁積流

濁積流(英語:turbidity current)是一種富含懸浮固體顆粒的高密度水流,其密度大於周圍海水,在重力驅動下順坡向下流動,多發生於大陸邊緣地區,常受地震、滑坡、風浪等因素觸發,是將陸源物質由淺海輸送到深海的重要機制,可在大陸邊緣或洋盆區形成濁流沉積。[1][2]

在最典型的海洋濁積流情況下,位於傾斜地面上的載有沉積物的水將向山下流動,因為它們的密度高於鄰近水域。濁積流背後的驅動力是重力作用,來於暫時懸浮在流體中的沉積物。這些半懸浮固體使含沉積物的水的平均密度大於周圍水的平均密度[3]。當這樣的水流流動時,它們通常會產生“滾雪球效應”,因為它們會攪動它們流過的地面,並聚集更多的沉積顆粒在它們的水流中。它們流過的地面會被沖刷和侵蝕[4]。一旦濁積流流到達深海平原(主要洋底)較平坦區域的較平靜的水域,攜帶的顆粒就會從水中沉澱出來。濁積流的沉積物稱為濁積岩[5]

參考文獻编辑

  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