Preliminary correlations of lithology and seismic reflectors in prograding Neogene carbonate of Great Bahama Bank

Conference · Fri Mar 01 04:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5529675

Eberli, G P ^[1]; Ginsburg, R N; Swart, P K; McNeill, D F; Kenter, J A.M. ^[2]

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1. Geological Inst., Zurich (Switzerland)
2. Univ. of Miami, FL (United States)

Excellent overall recovery of 80% in two continuous core borings provides the data on lithology necessary to calibrate prograding late Cenozoic sequences and their seismic signatures. Hole UNDA, 10 km inside the modern platform edge of Great Bahama Bank (GBB), penetrated onlapping and topset reflectors and a buried platform rim. The 500 m core revealed two platform sequences alternating with fine grainstone units with internal hardground surfaces. At hole CLINO, 5.5 km farther basinward, 657 m of core document the progradation of GBB with 150 m of shallow platform deposits and reefal sequences over mostly fine-grained, foraminifera-rich periplatform slope sediments with intercalations of coarser beds, some of which contain platform lithoclasts. Within these slope deposits, there is significant variation in the degree of cementation; friable, porous limestones alternate with well cemented beds. Preliminary correlations between lithofacies and seismic signatures suggest a strong influence of both the sedimentologic and diagenetic facies on the seismic signal. Major lithologic changes, such as from mudstone to coral-bearing packstone or from skeletal sand to reefal limestone, produce strong reflectors. These latter transitions also coincide with seismic sequence boundaries. Within the more homogeneous slope sections, where seismic reflection horizons are not characterized by a facies change, differential cementation seems to be responsible for the seismic signal. Nevertheless, three reflectors identified as sequence boundaries are overlain by units containing coarse-grained beds with platform lithoclasts and blackened grains, indicating that these deposits were shed during low sea level and represent parts of the lowstand systems tract.

• OSTI ID: 5529675
• Report Number(s): CONF-910403--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 75:3
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
BAHAMA ISLANDS
CARBONATE ROCKS
CENOZOIC ERA
CONTINENTAL MARGIN
CONTINENTAL SHELF
CORRELATIONS
DEPOSITION
DEVELOPING COUNTRIES
DIAGENESIS
DRILL CORES
GEOLOGIC AGES
GEOLOGIC HISTORY
GEOPHYSICAL SURVEYS
ISLANDS
LITHOLOGY
ROCKS
SEDIMENTARY ROCKS
SEISMIC SURVEYS
SURVEYS
TERTIARY PERIOD
WEST INDIES