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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 992

Last Page: 992

Title: Sedimentary Processes in Restricted Gulf Coast Estuarine System: Corpus Christi Bay, Texas: ABSTRACT

Author(s): Gerald L. Sideler, Charles E. Stelting

Article Type: Meeting abstract


Corpus Christi Bay is a shallow (< 5 m), restricted estuary that is typical of estuaries on the Texas Gulf Coast. The distribution pattern of bay-floor sediments indicates that the bay's interior is a depocenter for mud derived from multiple sources; the bay's marginal areas are composed mainly of residual sandy deposits derived from shoreline erosion of a Pleistocene substrate (Beaumont Formation) and a modern baymouth barrier (Mustang Island).

Synoptic time-sequence measurements of the bay's suspended sediment and hydrographic characteristics were taken by helicopter at 15 monitoring stations; the measurements represent 8 surveys conducted during a 2-year observation period. The measurements show a high degree of spatiotemporal variability and indicate a wind-dominated sediment-dispersal system. During all surveys, the bay was consistently turbid (mean baywide transmissivity < 15%/m); the mean baywide concentration of suspended sediment during individual surveys ranged from 11 mg/l to 52 mg/l. The suspended-sediment concentrations were primarily controlled by wind speed which determines the extent of wave-induced resuspension of bay-floor deposits; wind direction and tidal phase controlled the sediment-dispersal patterns

Texturally, the baywide mean grain size of suspended sediments during individual surveys ranged from very fine silt to clay (7.63 to 3.22^phgr), and mean silt/clay ratios were within the 0.68 to 1.38 range; the sediment was consistently poorly sorted. In contrast to suspended-sediment concentrations, which largely appear to be a short term response to recent wind conditions, sediment textures appear to be a longer term response to earlier wind conditions, thus suggesting that finer grained particulate matter has substantial residence time within the shallow water column.

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