The response of low to moderate sediment supply incised valley systems to episodic sea-level rises
- Rice Univ., Houston, TX (United States)
Low to moderate sediment supply incised valley systems (e.g., the Trinity, Sabine, and Lavaca rivers) are characterized by mud-dominated estuarine fill and by sedimentation that is limited to the valley cut during low sea level. In contrast, within the high sediment supply Brazos valley system substantial sedimentation has occurred between the lowstand valleys for at least the last 7000 years. Within the Trinity/Sabine incised valley system, sand prone facies include fluvial and tidal inlet deposits. Fluvial deposits are relatively uniform in thickness and distribution, while tidal inlets form discontinuous and pod-like deposits. The valley-fill stratigraphy consists of transgressive parasequences, whose bounding flooding surfaces can be mapped with core and high resolution seismic data. Each parasequences is represented by paired upper bay marsh/bayhead delta and tidal inlet/flood tidal delta facies. Coeval shoreline facies are reworked during the sea-level rise that terminates a particular parasequence. Over 200 sediment cores from the study area are used to define the shapes of these sand bodies, and to establish their origin based on grain sizes, sedimentary structures, and faunal assemblages. The stratigraphy interpreted from these low to moderate sediment supply incised valley systems imply sea level rose episodically during the last transgression. Rapid sea-level rises are responsible for development of isolated shelf sand deposits and may correlate to stream piracy events in the nearby Brazos system. Ongoing investigations concentrate on the distal portions of the incised valleys where they become the feeders to shelf margin deposits within the lowstand systems tract.
- OSTI ID:
- 7259582
- Report Number(s):
- CONF-910403--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 75:3; ISSN AABUD; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
Similar Records
The response of a high sediment yield depositional system to episodic rises in sea level: The record from the Brazos fluvial system, central Texas coast
Models for Holocene valley-fill sequences from high-resolution seismic facies of Galveston Bay
Related Subjects
580000* -- Geosciences
ALLUVIAL DEPOSITS
DEPOSITION
DEVELOPED COUNTRIES
FEDERAL REGION VI
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GEOLOGY
GEOMETRY
LEVELS
MATHEMATICS
NORTH AMERICA
RIVERS
ROCKS
SANDSTONES
SEA LEVEL
SEDIMENTARY ROCKS
SEDIMENTATION
STRATIGRAPHY
STREAMS
SURFACE WATERS
TEXAS
USA
VARIATIONS