Salt marsh deposits are developed along many tidal flat areas, lagoons, bays, etc. They are characterized by small thickness, special sedimentary structures, high organic content, growth of phanerogamous halophytes, and often by scarcity or absence of microfauna. A graphical representation of a section at Ameland (The Netherlands) is given, as well as radiographs of a sandy (Ameland) and a clayey (California) marsh sample. Little structural difference exists between the two.

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The Mississippi Fan is a broad, arcuate accumulation of Pleistocene deep-water sediments deposited in the eastern Gulf of Mexico. Multiple acoustical sub-bottom reflectors can be traced regionally across the entire fan, dividing this sediment body into sediment packages called fan lobes. Seven of these acoustical reflectors have been mapped and they divide the fan into seven fan lobes. Structure and isopach maps of these fan lobes reveal a general shift during the Pleistocene from west to east and toward deeper water. Each fan lobe is basically a channel-overbank complex with differing morphology and channel characteristics that allow it to be divided into upper, middle, and lower fan physiographic regions.The upper fan region of the modern fan lobe connects to the Mississippi Canyon and is characterized by a nearly filled, large erosional channel with broad levees. A smaller, central channel is cut into the large channel fill.The middle fan region starts near the major break in slope. It is convex in cross section with a sinuous channel at its apex. The size of the channel as well as its sinuosity decrease downfan. An acoustical high-amplitude zone near the base of the channel fill coincides with coarse-grained material.The lower fan region starts where the single sinuous channel pattern changes into a set of near-parallel surface images, interpreted to be former channel courses. Only one channel was active at a given time and its life span was geologically short before it shifted to a new position. At the distal end, these channels may bifurcate before becoming unrecognizable on high-resolution seismic records and sediment deposition changes from a confined to an unconfined mode. The latter is characterized by sheet-sand deposition containing a significant amount of sand that originated from upper slope and shelf environments.Major objectives for drilling the Mississippi Fan were to place the fan lobes into a time-stratigraphic framework, to determine if the midfan channel is migratory in nature, to establish the lithological characteristics of the acoustical high-amplitude zone present near the bottom of the channel fill, to analyze if sand is transported to the lower fan and in which depositional mode it is emplaced, to confirm or modify existing fan models, and to determine the physical and chemical characteristics of these deep-sea fan deposits.Nine sites were occupied on the Mississippi Fan, four (Sites 621, 622, 617, and 620) on the middle fan, four (Sites 623, 624, 615, and 614) on the lower fan, and one (Site 616) on the flank of the youngest fan lobe and within a surface slump deposit. Most of the holes penetrated only the youngest fan lobe.In addition to these nine sites, two sites (618 and 619) were occupied on the continental slope off Louisiana in intraslope basins formed as the result of active salt diapirism. Orca Basin (Site 618), characterized by a 200-m-thick anoxic, high salinity layer of bottom water, was expected to provide a complete upper Neogene stratigraphical and chemical record. Howev...