Unique signature of carbonate strata and the development of depositional sequence and systems tract models for ramps, rimmed shelves, and detached platforms
- ARCO Oil and Gas Co., Plano, TX (United States)
Eustasy, tectonic subsidence, and sedimentation rates are the most important variables controlling the development of depositional sequences in both siliciclastic and carbonate depositional provinces. However, both sediment types have unrelated depositional origins and they respond differently to relative changes of sea level. For example, carbonate environments generate sediment and create sea-floor topography (rimmed shelf margins and steep slopes), and carbonate rocks weather into karst topography during lowstands. These differences are manifested by unusual and perhaps unique stratal patterns, especially in rimmed shelves with depositional versus bypass margins and ramps characterized by fringing versus barrier shoals. Furthermore, rimmed shelves may exhibit marineward onlap of shelf strata (carbonate, siliciclastic, or evaporite) against carbonate shelf margin buildups and carbonate clinoforms that prograde landward from rimmed margins and downlap deep shelf strata. When combined with environmental factors (morphology, continental linkage, marine setting, latitude, magnitude of shelf, climatic factors, sediment type, and age), significant variations in systems-tract geometries and stratal patterns are likely to result. Factors listed above must be integrated with established facies models in order to arrive at sequence and systems tracts models that adequately address carbonate facies. As should be the case with all models, however, they are not meant to serve as rigid templates within which all carbonate sequences must fit. They are meant, instead, to function as working hypotheses to help geologists visualize how and why carbonate strata were laid down and fit together as they do.
- OSTI ID:
- 5677250
- Report Number(s):
- CONF-910403-; CODEN: AABUD
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:3; Conference: Annual meeting of the American Association of Petroleum Geologists (AAPG), Dallas, TX (United States), 7-10 Apr 1991; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBONATE ROCKS
DEPOSITION
PETROLOGY
SEDIMENTARY BASINS
GEOLOGIC MODELS
CONTINENTAL SHELF
GEOGRAPHICAL VARIATIONS
GEOLOGIC HISTORY
LITHOLOGY
PRECIPITATION
SEA LEVEL
SEDIMENTATION
STRATIGRAPHY
CONTINENTAL MARGIN
GEOLOGIC STRUCTURES
GEOLOGY
LEVELS
ROCKS
SEDIMENTARY ROCKS
SEPARATION PROCESSES
VARIATIONS
580000* - Geosciences