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GEOREF RECORD

Terrace inundation as an autocyclic mechanism for parasequence formation; Galveston Estuary, Texas, U.S.A.

Antonio B. Rodriguez, John B. Anderson and Alexander R. Simms
Terrace inundation as an autocyclic mechanism for parasequence formation; Galveston Estuary, Texas, U.S.A.
Journal of Sedimentary Research (July 2005) 75 (4): 608-620

Abstract

Architecture of late Quaternary incised-valley fills is commonly attributed to the interplay between sea-level rise, sediment supply, and hydrodynamic processes. Inundation of fluvial terraces is commonly overlooked as an autocyclic mechanism for formation of parasequences. If the rate of sea-level rise and sediment supply is constant, architecture of terraced incised-valley fills will likely show backstepping parasequences. The control that variable antecedent topography has on architecture of incised-valley fills is examined in the Trinity incised valley, Texas. The Trinity valley is characterized by a series of downward-stepping terraces, and the Galveston Estuary formed above this irregular antecedent topography. Flooding surfaces, recognized in core by a decrease in sedimentation rates and a change from delta-plain to central-basin facies, formed at -14 m, 8,200 cal. yr BP and -10 m, 7,700 cal. yr BP, matching depths of the relatively flat fluvial terraces. Flooding surfaces formed rapidly and represent entire reorganization of the estuarine complex. Across the -10 m flooding surface, the river mouth and bay-head delta shifted landward at a rate of -6.5 km per century and the associated barrier shoreline was stranded on the inner continental shelf, forming Heald Bank. Flooding surfaces formed as the rate of sea-level rise was decreasing, and are not associated with a decrease in sediment delivery to the estuary. As sea level inundates relatively flat fluvial terraces, rates of transgression rapidly increase, resulting in a sudden increase in accommodation space and an associated landward shift in coastal facies. Backstepping parasequences are inherent to the architecture of terraced incised-valley fills.


ISSN: 1527-1404
EISSN: 1938-3681
Serial Title: Journal of Sedimentary Research
Serial Volume: 75
Serial Issue: 4
Title: Terrace inundation as an autocyclic mechanism for parasequence formation; Galveston Estuary, Texas, U.S.A.
Affiliation: University of Alabama, Department of Geological Sciences, Tuscaloosa, AL, United States
Pages: 608-620
Published: 200507
Text Language: English
Publisher: Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
References: 63
Accession Number: 2005-058893
Categories: Quaternary geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., 1 table, sketch maps
N29°19'60" - N29°45'00", W95°04'60" - W94°40'00"
Secondary Affiliation: Rice University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 200536
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