Seismic stratigraphy and facies of Continental Slope and rise seaward of Baltimore Canyon Trough
As part of a survey of the US continental rise seaward of the northern Baltimore Canyon Trough, four major depositional sequences were mapped on a grid of 2350 km of multichannel seismic reflection profiles. The sequences, which range in age from Jurassic (.) to Quaternary, record a gradual sedimentary buildup of fine-grained onlapping and slope-front fill. A broad wedge of Jurassic-age (.) sediment up to 5 km thick was deposited seaward of a conspicuous platform. During the Cretaceous, the slope-rise transition became much gentler, and sequences are more blanket-like because the declivity seaward of the platform was smoothed and filled by fine-grained clastic sediments and thin-bedded limestones. The main constructional phase for the continental rise was during the Cenozoic, when a thick (0.1-2.4 km) wedge formed seaward of the shelf edge in response to major fluctuations in sea level and erosion of the gentle, ancestral continental slope. The Cenozoic rise section can be subdivided into two main sequences separated by a conspicuous unconformity. The lower sequence is mostly a blanket (0.2-0.8 km thick) of Paleogene hemipelagic ooze and claystone. The sequence above the unconformity is a complex association of Neogene slump deposits, turbidites, hemipelagic clays, and channel fill that thickens seaward to 2.2 km under the middle continental rise. The final phase of rise construction was caused by widespread fluctuations in coastal onlap. These regressions resulted in deltaic outward-building on the shelf, extensive Pleistocene landward erosion of the slope, and the accumulation of a broad sedimentary apron on the rise. 24 figures, 4 tables.
- Research Organization:
- Geological Survey, Woods Hole, MA
- OSTI ID:
- 6002769
- Journal Information:
- AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States), Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Vol. 71:9; ISSN AABUD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
ATLANTIC OCEAN
BALTIMORE CANYON
CARBONATE ROCKS
CENOZOIC ERA
CONTINENTAL MARGIN
CONTINENTAL SLOPE
CRETACEOUS PERIOD
GEOLOGIC AGES
GEOLOGY
GEOPHYSICAL SURVEYS
JURASSIC PERIOD
MESOZOIC ERA
ROCKS
SANDSTONES
SEAS
SEDIMENTARY ROCKS
SEISMIC SURVEYS
STRATIGRAPHY
SURFACE WATERS
SURVEYS
TERTIARY PERIOD