Stratigraphic and sedimentologic response to Late Quaternary climate change and glacio-eustasy, Colorado River, Gulf Coastal Plain of Texas

Conference · Wed Jan 01 00:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:6137345

Blum, M D ^[1]

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1. Southern Illinois Univ., Carbondale, IL (United States). Dept. of Geology

This paper summarizes results of investigations of the Colorado River, Gulf Coastal Plain of Texas, which provides a detailed record of fluvial response to late Quaternary climatic change and glacio-eustatic sea level rise. Four allostratigraphic units of late Pleistocene through modern age are differentiated in the bedrock-confined lower Colorado valley on the Inner Coastal Plain. Here up to 10 meters of late Pleistocene sediments underlie a terrace at 17--20 meters above the present-day channel. Two distinct allostratigraphic units underlie an extensive Holocene terrace at 12--14 meters above the present-day channel. Allostratigraphic units and bounding disconformities correlate with climatic changes that have been identified from paleobiological data, and represent stratigraphic response to changes in the relationship between discharge and sediment supply. In addition, changes in sedimentary facies through time represents a response to changes in climate coupled with a protracted degradation of upland soil mantles. This degradation of soils altered the rate at which precipitation inputs were transferred to stream channels as runoff, which led to increases in the peakedness of flood hydrographs and changes in the relative importance of channel versus floodplain depositional environments. Increased flood stages during the late Holocene promoted the increasing importance of floodplain construction by vertical accretion, and late Holocene to modern allostratigraphic units contain thick vertical accretion facies. These same allostratigraphic units and component facies persist downvalley to the Outer Coastal Plain, but stratigraphic architecture changes as a result of the last glacio-eustatic cycle. Here late Holocene and modern sediments onlap and bury late Pleistocene and early to middle Holocene stratigraphic units that were emplaced during the last sea level lowstand and the transgression that followed.

• OSTI ID: 6137345
• Report Number(s): CONF-921058-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
QUATERNARY PERIOD
PALEOCLIMATOLOGY
SEDIMENTARY BASINS
STRATIGRAPHY
TEXAS
CLIMATIC CHANGE
COLORADO RIVER
FLUCTUATIONS
GEOLOGIC HISTORY
RESPONSE FUNCTIONS
SEA LEVEL
SEDIMENTATION
US GULF COAST
CENOZOIC ERA
DEVELOPED COUNTRIES
FUNCTIONS
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
LEVELS
NORTH AMERICA
PALEONTOLOGY
RIVERS
STREAMS
SURFACE WATERS
USA
VARIATIONS
580000* - Geosciences