Carbonate-slope failures as indicators of sea-level lowerings

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

OSTI ID:5529811

Cook, H E ^[1]; Taylor, M E ^[2]

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1. Geological Survey, Menlo Park, CA (United States)
2. Geological Survey, Denver, CO (United States)

Occasionally, carbonate-slope failures of such a magnitude occur that immense volumes of material move downslope as submarine slides and boulder-bearing debris flows. These spectacular deposits can be triggered by earthquakes or tsunamis. However, when such deposits are regionally widespread or are on separate lithospheric plates, at times of sea-level lowering, trigger mechanism is most likely eustatic sea-level fluctuations. The authors propose that during the initial phases of a sea-level lowering, slope and/or platform-margin collapse can happen, owing to gravitational instability of partially cemented carbonates. Fragments of the margins of the early Paleozoic proto-Pacific Ocean are found in widely separated terranes, including western North America and southern Kazakhstan (USSR). Coeval carbonate-slope and platform-margin failures occurred in both areas during the Late Cambrian and Early Ordovician. Up to 75-km-long segments of these carbonate slopes and platform margins collapsed and were transported seaward as submarine slides and megabreccia debris flows. These catastrophic events contributed to the development of 500-m-thick carbonate submarine fans and aprons. Slope and platform-margin failures also correlate with solution breccia and faunal disconformities in platform-interior sites. They interpret these widely separated yet coeval mass-transport processes to have happened during rapid oceanward progradation of their respective carbonate margins, in combination with several eustatic sea-level lowerings.

• OSTI ID: 5529811
• 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

Related Subjects

58 GEOSCIENCES
CARBONATE ROCKS
DEPOSITION
CONTINENTAL SLOPE
GROUND MOTION
SEA LEVEL
CLIMATE MODELS
VARIATIONS
CAMBRIAN PERIOD
GEOLOGIC HISTORY
GEOLOGIC MODELS
OCEANOGRAPHY
ORDOVICIAN PERIOD
SLOPE STABILITY
CONTINENTAL MARGIN
GEOLOGIC AGES
LEVELS
MATHEMATICAL MODELS
MOTION
PALEOZOIC ERA
ROCKS
SEDIMENTARY ROCKS
STABILITY
580000* - Geosciences