Sandstone Depositional Environments
Sandstone Depositional Environments has proven to be one of AAPG's all-time best sellers, with multiple reprints and extensive use as a university textbook. The volume is specifically designed for the non-sedimentologist, the petroleum geologist, or the field geologist who needs to use sandstone depositional environments in facies reconstruction and environmental interpretations. Prediction of subsurface sandstone trends, diagenetic style, and continuity of reservoir porosity is strongly dependent on an understanding of original depositional environments. The volume consists of twelve chapters, each covering a major environmental setting for sandstone deposition from terrestrial to deep marine (glacial, eolian, alluvial fan, lacustrine, fluvial, deltaic, estuarine, tidal flat, barrier island, continental shelf, continental slope, and submarine fan). For each environment the modern depositional processes are described and compared to subsurface examples, with abundant illustrations and photographs. Different scales and perspectives are reviewed, using aerial photos, maps, seismic, cross sections, outcrops, cores, and thin sections. Each chapter is organized in a manner that it can be used effectively and independently for teaching purposes or as an analog reference for field study and subsurface interpretation.
Tidal Flats and Associated Tidal Channels
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Published:January 01, 1982
Abstract
Tidal flats occur on open coasts of low relief and relatively low energy and in protected areas of high-energy coasts associated with estuaries, lagoons, bays, and other areas lying behind barrier islands. Conditions necessary for formation of tidal flats include a measurable tidal range and the absence of strong wave action.
Extent of tidal flats on present-day coasts varies greatly and includes small, locally restricted areas of several hundred square meters or regional features extending over hundreds of square kilometers, (coast of the Netherlands, Germany, and Denmark and salt marshes along the Atlantic coast of the United States). Occasional confusion in terminology occurs because tidal flats may carry local geographic names such as "lagoon, bay, salt marsh, etc." Although the term tidal deposit has become popular in recent years, in this chapter we primarily describe tidal flats and genetically related tidal channels (dominantly subtidal) representing two specific types of tidal deposits.
Early detailed studies on tidal flats were carried out on the North Sea coast by German and Dutch geologists, and these classic studies have become models for subsequent investigations and interpretation of ancient tidal flat deposits. There is, however, considerable variation in tidal flats, depending on sediment types and availability, presence or absence of vegetation, tide range, and coastal energy and morphology.Tidal flats are subdivided into intertidal and subtidal environments which control facies distribution. Parts of the tidal flat lying between high and low tide range, the intertidal zone, make up the major areal extent of the tidal flat.