Late Pleistocene--Early Holocene paleochannel systems and the episodic sea level framework on the continental shelf, south of Chesapeake Bay entrance, Virginia

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5951535

Chen, Z Q; Hobbs, III, C H ^[1]; Kimball, S M ^[2]

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1. Coll. of William and Mary, Gloucester Pt., VA (United States)
2. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Environmental Science

More than 600 km of closely-spaced, high-resolution seismic lines on the continental shelf south of the Chesapeake Bay entrance enables recognition of three major paleochannel systems. Fourteen aminostratigraphic samples from paleochannel fill, an overlying barrier-spit complex, and basal strata in a suite of vibracores yield A/I values ranging from 0.01 to 0.55. Ages for the three paleochannel systems are thus assigned to oxygen isotope stages 2, 6, and 8 from top to bottom, corresponding to 30 [plus minus]10 ka, 150 [plus minus]20 ka, and 260 [plus minus] 20 ka BP respectively. These paleochannel systems are apparently compatible in age with the ancient valley systems identified recently beneath Chesapeake Bay. Based on the examination of lithology, sedimentary structure, sedimentologic character, and stratigraphic correlation among the vibracores, a preliminary reconstruction of depositional environments for the fill sequences is attempted. The spatial and temporal variation of the multilayered fill sequences is tested and further simplified using a Q-mode factor analysis. The analysis results a schematic picture of depositional environmental evolution of the fill sequences from fluvial-estuarine dominated environments, through a transitional stage, into shallow marine (beach-surf zone-shoreface-inner shelf) environments during the late Pleistocene to early Holocene time.

• OSTI ID: 5951535
• Report Number(s): CONF-9304188--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:4
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
ATLANTIC OCEAN
BAYS
CHESAPEAKE BAY
COASTAL WATERS
CONTINENTAL MARGIN
CONTINENTAL SHELF
DEVELOPED COUNTRIES
GEOLOGIC HISTORY
GEOLOGY
GEOMORPHOLOGY
GEOPHYSICAL SURVEYS
ISOTOPES
LITHOLOGY
NORTH AMERICA
OXYGEN ISOTOPES
PETROLOGY
SEAS
SEDIMENTATION
SEISMIC SURVEYS
STRATIGRAPHY
SURFACE WATERS
SURVEYS
USA
VIRGINIA