Seismic and geologic characteristics of drowning events on carbonate platforms
- Amoco Production Co., Houston, TX (USA)
Carbonate platform drowning events were recorded in Late Jurassic-Early Cretaceous carbonates of the Baltimore Canyon area, and early Miocene carbonates of the Pearl River Mouth basin. Cursory examination of seismic data from both areas would suggest that the platforms appear to fit the classic definition of a drowning unconformity. Lithologic and paleontologic data however, indicate that depositional hiatuses vary widely in each area (from 0-25 Ma in the Baltimore Canyon area, to no hiatus, but a condensed section in the Pearl River Mouth basin). The sedimentary sequence produced during a drowning event (the drowning sequence) in both areas is gradational with underlying shallow platform carbonates and, in some places, overlying deeper marine limestones and shales. Facies models illustrate that drowning event, in general, can appear as instantaneous or gradual changes in lithologic and seismic data. However, evidence from platforms adjacent to continental margins (Baltimore Canyon) and isolated open ocean atolls and banks (Pearl River Mouth basin) indicates that their response to drowning is different. In addition, bypass/erosional and accretionary carbonate platforms also respond somewhat differently to drowning events. The geologic characteristics of drowning events on carbonate platforms include gradational lower (and sometimes upper) contacts, chemical sedimentation, open-marine shelf sediments, and variable loss of time at the upper boundary. Late-growth shelf margin reefs can also be a diagnostic feature of drowned platforms. Seismic characteristics include horizontal to subhorizontal basinal marine onlap and basin-parallel reflector continuity above the carbonate sequence boundary. Proper recognition of the seismic and geologic characteristics of drowning events can lead to better reservoir-seal predictions, and to correct reconstruction of the depositional and tectonic/eustatic history of an area.
- OSTI ID:
- 6729494
- Report Number(s):
- CONF-900605--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (USA), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Vol. 74:5; ISSN AABUD; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
Similar Records
Sequence architecture of Lower Cretaceous carbonate shelf, Gulf Coast
Stratigraphic framework and petroleum potential of northeastern Baltimore Canyon Trough, mid-Atlantic outer Continental Shelf
Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
CARBONATE ROCKS
CENOZOIC ERA
CRETACEOUS PERIOD
DEPOSITION
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
JURASSIC PERIOD
LITHOLOGY
MESOZOIC ERA
MINERAL RESOURCES
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SEDIMENTATION
SEISMIC SURVEYS
SURVEYS
TERTIARY PERIOD