Evidence for unconformities in the Cenozoic of the central and south Texas Continental Shelf from regional electric log and seismic cross sections

Conference · Sat Sep 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5991499

Blood, T; LaPointe, A E; Cran, C E; Stanczyk, M F ^[1]

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1. Dept. of the Interior, New Orleans, LA (USA)

Regional stratigraphic studies conducted by the Minerals Management Service, Gulf of Mexico, Outer Continental Shelf Region, on the offshore Texas shelf have identified at least eight major and several minor unconformities within the Cenozoic sediments. The identified erosional features associated with these unconformities include structural truncation, valley incision, and submarine canyon formation, which are the characteristics of a Type I unconformity as defined by Vail. There is also evidence for onlap by the overlying beds. The major unconformities are observed on the upthrown and downthrown sides of regional growth fault systems that are roughly parallel to the Texas coast. Where data quality permits, the major unconformities are identified over most of the Texas shelf. The minor unconformities are observed in the expanded sections on the downthrown blocks of major growth faults only. Although these erosional surfaces may also be Type I unconformities, no evidence of erosion is observed on the upthrown sides of the major growth faults. The unconformities of Oligocene and lower and middle Miocene age were initially interpreted from electric log correlations and subsequently verified on seismic data. The upper Miocene and younger unconformities were first recognized through seismic stratigraphy studies and then tied to electric log correlations. Most of the unconformities are observed near partially eroded diapiric ridges located along what was the outer shelf/upper slope area at the time of the erosion. A major upper Miocene unconformity is observed in the inner shelf/transitional environment of deposition in Matagorda and Mustang Island areas. This erosional surface was most likely formed by wave erosion during the subsequent transgression after deposition of the Discorbis 12 age sediments.

• OSTI ID: 5991499
• Report Number(s): CONF-9010204--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:9
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
ATLANTIC OCEAN
CARIBBEAN SEA
CENOZOIC ERA
CONTINENTAL MARGIN
CONTINENTAL SHELF
CROSS SECTIONS
ELECTRIC LOGGING
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
GEOPHYSICAL SURVEYS
GULF OF MEXICO
NORTH AMERICA
OFFSHORE SITES
SEAS
SEISMIC SURVEYS
STRATIGRAPHY
SURFACE WATERS
SURVEYS
TERTIARY PERIOD
TEXAS
USA
WELL LOGGING