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Title: Evidence for drainage displacement by sea-level fluctuation from the inner continental shelf, Virginia

Abstract

The trace of the ancestral Susquehanna River across the modern coastline has been displaced over 40 km southward since the mid to late Pleistocene. High-resolution seismic reflection data from the inner shelf suggest that submerged-channel fill is responsible for time-lagged channel shifting during subsequent regressions. Traditional channel-shift models suggest that migrating spit platforms progressively fill a portion of the updrift side of a channel and force excavation of an equivalent portion of material from the downdrift side. Channel migration results in a continuous broad channel-scar representing the integrated positions of channels at time scales of 10[sup 0] to 10[sup 2] years. Seismic data adjacent to the Delmarva Peninsula illustrate three separate Pleistocene lowstand pathways for the ancestral Susquehanna River. Evidence of continuous migration in these channels is minor. Channel shifting apparently occurred at time scales of 10[sup 4] to 10[sup 5] years and involved major shifts in water level invoked by transgression and regression. The channel shift is operative during regression when the fluvial channel is not necessarily confined to its previous antecedent lowstand channel, and may jump laterally to a new location. time-lagged channel jumps are related to spit growth during major high stand events and widespread regional flooding.more » During these events, the Susquehanna was no longer confined to its fluvial valley but spread into broad ancestral Chesapeake Bays formed in drowned Susquehanna flood plains. Sediments of migrating spit platforms and bay entrance shoals filled the drowned channels in the floors of the bays. During subsequent regressions, the bays shrunk and the drainage of the ancestral Susquehanna cut new pathways to the shelf edge in adjacent parts of the flood plain.« less

Authors:
;  [1]
  1. Old Dominion Univ., Norfolk, VA (United States). Dept. of Oceanography
Publication Date:
OSTI Identifier:
6112081
Report Number(s):
CONF-9304188-
Journal ID: ISSN 0016-7592; CODEN: GAAPBC
Resource Type:
Conference
Journal Name:
Geological Society of America, Abstracts with Programs; (United States)
Additional Journal Information:
Journal Volume: 25:4; Conference: 42. annual Geological Society of America (GSA) Southeastern Section meeting, Tallahassee, FL (United States), 1-2 Apr 1993; Journal ID: ISSN 0016-7592
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; CONTINENTAL SHELF; SEISMIC SURVEYS; PLEISTOCENE EPOCH; SEA LEVEL; VIRGINIA; ALLUVIAL DEPOSITS; FLUCTUATIONS; GEOLOGIC HISTORY; GEOMORPHOLOGY; RIVERS; CENOZOIC ERA; CONTINENTAL MARGIN; DEVELOPED COUNTRIES; GEOLOGIC AGES; GEOLOGIC DEPOSITS; GEOLOGY; GEOPHYSICAL SURVEYS; LEVELS; NORTH AMERICA; QUATERNARY PERIOD; STREAMS; SURFACE WATERS; SURVEYS; USA; VARIATIONS; 580000* - Geosciences

Citation Formats

Oertel, G F, and Foyle, A M. Evidence for drainage displacement by sea-level fluctuation from the inner continental shelf, Virginia. United States: N. p., 1993. Web.
Oertel, G F, & Foyle, A M. Evidence for drainage displacement by sea-level fluctuation from the inner continental shelf, Virginia. United States.
Oertel, G F, and Foyle, A M. Mon . "Evidence for drainage displacement by sea-level fluctuation from the inner continental shelf, Virginia". United States.
@article{osti_6112081,
title = {Evidence for drainage displacement by sea-level fluctuation from the inner continental shelf, Virginia},
author = {Oertel, G F and Foyle, A M},
abstractNote = {The trace of the ancestral Susquehanna River across the modern coastline has been displaced over 40 km southward since the mid to late Pleistocene. High-resolution seismic reflection data from the inner shelf suggest that submerged-channel fill is responsible for time-lagged channel shifting during subsequent regressions. Traditional channel-shift models suggest that migrating spit platforms progressively fill a portion of the updrift side of a channel and force excavation of an equivalent portion of material from the downdrift side. Channel migration results in a continuous broad channel-scar representing the integrated positions of channels at time scales of 10[sup 0] to 10[sup 2] years. Seismic data adjacent to the Delmarva Peninsula illustrate three separate Pleistocene lowstand pathways for the ancestral Susquehanna River. Evidence of continuous migration in these channels is minor. Channel shifting apparently occurred at time scales of 10[sup 4] to 10[sup 5] years and involved major shifts in water level invoked by transgression and regression. The channel shift is operative during regression when the fluvial channel is not necessarily confined to its previous antecedent lowstand channel, and may jump laterally to a new location. time-lagged channel jumps are related to spit growth during major high stand events and widespread regional flooding. During these events, the Susquehanna was no longer confined to its fluvial valley but spread into broad ancestral Chesapeake Bays formed in drowned Susquehanna flood plains. Sediments of migrating spit platforms and bay entrance shoals filled the drowned channels in the floors of the bays. During subsequent regressions, the bays shrunk and the drainage of the ancestral Susquehanna cut new pathways to the shelf edge in adjacent parts of the flood plain.},
doi = {},
journal = {Geological Society of America, Abstracts with Programs; (United States)},
issn = {0016-7592},
number = ,
volume = 25:4,
place = {United States},
year = {1993},
month = {3}
}

Conference:
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