Deltaic deposits

The analysed sandstones with accompanying mudstones, claystones and subordinate conglomerates are of fluvial origin and interlayered with marine and deltaic deposits (Waksmundzka 2008). 

Frazier, D.E. (1967) Recent deltaic deposits of the Mississippi River their development and chronology Gulf Coast Assoc. Geol. Soc. Trans. 17, 287-315. 

Galloway, W.E. (1975) Process framework for describing the morphologic and stratigraphic evolution of deltaic depositional systems. In Deltas, Models for Exploration (Broussard, M.L., ed.), pp. 87-98, Houston Geological Society, Houston, TX. 

Land subsidence in deltas can be associated with two factors (1) tectonic subsidence of the seabed and its peripheral parts and (2) gradual thickening (and dehydration) of young deltaic deposits under the pressure of their own weight. Extraction of groundwater and gas can also cause the subsidence of deltaic deposits. Worldwide, river deltas are the main areas of land subsidence. It can reach 10 mm year 1 (the Mississippi River mouth) and more [3]. 

It is impossible to accurately assess the contribution of the subsidence of deltaic deposits to the RSLR, because the amount of subsidence greatly varies (both in space and time) within the same delta. The only way to assess this contribution is to compare the actual level rise (RSLR) with the average rates of the eustatic level rise of the sea. 

The effect of waves on the seashores, including the delta coasts, depends on the energy of waves. Waves are capable of destroying the deltaic deposits in the periods of low sediment load and to slow down the progradation of deltas into the sea, as well as to transport sandy sediments along the delta coastlines and to form beaches and sand coastal bars. In some cases, separate deltaic lobes were completely destroyed after the water and sediment input to the deltas had ceased (the deltas of the Danube, Rioni rivers). 

Amazon deltaic deposits are reworked extensively by tides and waves (Geyer et al. 1996, Kineke et al. 1996, Sternberg et al. 1996). Over 10% of the Amazon subaqueous delta is covered by fluid muds (suspended solid concentration > 10 g L O, which can be several meters thick in some places. These sediments and the water contained therein can be mobilized by changes in frontal dynamics or by fortnightly tidal cycles (Kineke et al. 1996, Geyer et al. 1996). Even in nonfluid mud areas, the sediment can be... 

The magnitude of this loss is thus substantial, and comparable to flux estimates for the delivery of terrigenous OC to the oceans (Figure 1). However, while the above studies imply low burial efficiencies for fluvial POM in deltaic environments, it is uncertain whether the apparent losses of riverine POM reflect its complete mineralization or export to the ocean interior either in dissolved or particulate form (Edmond et al., 1981). Moreover, the extent of terrestrial OC export and burial from river systems that do not form deltaic deposits is less weU constrained. 

The location of Gardinier s plant in relation to Tampa Bay is indicated in Figure 1. Two canals discharge processing wastes into the Bay. A deltaic deposit of fluorite that may be the only such deposit of sedimentary fluorite known in the world is located at the mouth of both canals. In cross-section, the fluorite deposit is about 3 in. thick at the... 

Mertens, G., Spies, E.D. Teyssen, T. (1983) The Luxemburg Sandstone Formation (Lias), a tide-controlled deltaic deposit. Ann. Soc. geol. Belg., 106, 103-109. 

Fig. 3. Schematic diagram of the Bossier sands showing high-stand progradational, deltaic depositional model.

Submerged sloping (10° to 25°) stratified deltaic deposits of sandy pebbles and loose sand... 

Most prevalent type of slide involved lateral spreading (up to 2 ft). Alluvial deposits along streams and rivers (deltaic deposits) and loosely placed sandy fUls... 

Suitable These are areas underlain by shallow estuarine/deltaic deposits (clay, silt with lesser amounts of sand and gravel and variable organic matter) and riverine deposits (sand, silt and clay with minor to moderate plant remains) of less than 5 m sand. Shallow peat (less than 1 m) normally occurs as narrow belts. These areas have a moderately deep foundation level or rockline (10 to 15 m) with minor to moderate amounts of subsidence expected and fair amount of fill required. 

Class III Moderately to highly compressible areas underlan by riverine deposits and estuarine/deltaic deposits. 

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