Clay mineralogy of contrasting mudflow and distal shelf deposits on the Mississippi River delta front

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Mass movement processes are the most important transport agents on the modern delta front. Changes in relative abundances of kaolinite, illite, and smectite proved to be valuable descriptors for distinguishing mudflow deposits (derived from the shallow delta front) from outer shelf/upper slope sediments. Fine-grained sediments, rapidly deposited from the turbid distributary plumes in the upper delta front, are typically high in smectite relative to illite and kaolinite. Distal shelf and upper slope sediments display an increased abundance of kaolinite and illite at the expense of smectite. Shifts in abundances of clay minerals define the bases and internal stratigraphy of complex mudflows.