ISSN:
1432-1157
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Geologie und Paläontologie
Notizen:
Abstract Cyclic sequences occur worldwide in nearly every stratigraphic sequence; they are particularly well developed in marine deposits associated with large river systems. Superimposed on those cycles attributed to shifting sites of deposition are those related to high-frequency sea level changes. The large data base for this study (including 471 deep foundation borings, thousands of line kilometers of high-resolution seismic, and sedimentological and dating analyses) represents the most complete information on high-resolution chronostratigraphy and lithostratigraphy that is available on any modern continental shelf/upper slope. These data are used to document sedimentological characteristics and spatial depositional patterns during three complete sea level cycles over the entire continental shelf/upper slope of offshore Louisiana. Sedimentation during periods of high sea level is characterized by: 1) thin, slowly accumulated depositional sequences, referred to as condensed sections, 2) calcareous-rich deposits, including hemipelagic sediments and shell hashes, and 3) wide lateral continuity. Sedimentation during periods of low sea level is characterized by; 1) variable-thickness, rapidly accumulated sequences referred to as expanded sections, 2) coarse-grained elastic deposits, including abundant sands and gravels, and 3) well-defined depositional trends. Even though the data set covers only a short period of geologic time (240 000 yrs), these high frequency events are responsible for the deposition of excellent reservoir-quality facies in well-defined and predictable trends.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF02330967
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