Barrier backbeach shell assemblages from the central Texas Gulf Coast

Journal Article · Wed Aug 01 00:00:00 EDT 1990 · Palaois; (United States)

DOI:https://doi.org/10.2307/3514890· OSTI ID:5589568

Albertzart, L S; Wilkinson, B H ^[1]

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1. Univ. of Michigan, Ann Arbor (USA)

Lateral variation in the abundance, taxonomic composition and amount of abrasion of approximately 14,000 mollusc shells, from 135 km of backbeach along Matagorda Island and Matagorda Peninsula of the central Texas coast, primarily reflect long-term patterns of shoreline progradation and recession. Disarticulated shell is concentrated as a gravel lag during landward transport of barrier island/peninsula sediment from storm washover and during lateral transport by fairweather longshore currents. Taxonomic dominance within any backbeach area directly relates to long-term Holocene patterns of shoreline migration. Shell along progradational Matagorda Island is largely derived from gulfward shoreface communities and valves of normal marine species are predominant. Shell along recessive beaches of Matagorda Peninsula, on the other hand, is primarily derived from the erosion of older bay-estuarine facies now exposed to shoreface currents, and values of brackish lagoonal species are predominant. Degree of valve abrasion reflects both the residence time of shell in shoreface settings and occurrence of shell with coarse, poorly sorted sediment. Central Texas coast backbeach molluscan death assemblages largely reflect a time-averaged census of both living communities and older shell assemblages that are sampled over an along-shore length of several kilometers and over a shore-to-basin distance of several hundred meters. These assemblages, accumulated over a time span of several thousand years, reflect the spatial and the temporal proximity of specific sedimentary environments to sites of sediment accumulation. Backbeach shell assemblages record both the ecologic preference of individual taxonomic groups to specific environmental parameters as well as the dominant processes of sediment transport in littoral depositional systems.

• OSTI ID: 5589568
• Journal Information: Palaois; (United States), Vol. 5:4
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
02 PETROLEUM
GEOLOGIC FORMATIONS
PALEONTOLOGY
GULF COAST
ABRASION
DEPOSITION
ENVIRONMENTAL TRANSPORT
EROSION
FOSSILS
GEOLOGIC HISTORY
ISLANDS
MOLLUSCS
QUATERNARY PERIOD
SEA LEVEL
SEDIMENTARY ROCKS
SEDIMENTS
STORMS
TEXAS
WATER CURRENTS
ANIMALS
AQUATIC ORGANISMS
CENOZOIC ERA
CURRENTS
DEVELOPED COUNTRIES
DISASTERS
FEDERAL REGION VI
GEOLOGIC AGES
INVERTEBRATES
LEVELS
MASS TRANSFER
NORTH AMERICA
ROCKS
USA
580000* - Geosciences
020200 - Petroleum- Reserves
Geology
& Exploration