The Holocene valley fill sequence in south Louisiana: A geological and geotechnical interpretation based on results of two deep cores

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5932313

Kuecher, G J; Roberts, H H; Suhayda, J H ^[1]; McGinnis, L D ^[2]

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1. Louisiana State Univ., Baton Rouge, LA (United States)
2. Argonne National Lab., IL (United States)

The Louisiana Geological Survey--US Geological Survey cooperative research program concerning wetland subsidence in Terrebonne and Lafourche Parishes, Louisiana, funded two deep research borings, each of which recovered core of the entire Holocene valley fill. These boreholes, 22 km apart in dip direction, were logged by porosity and resistivity tools and calibrated to cone penetrometer and seismic profiles immediately offsetting them. Major deltaic cycles and ravinement surfaces were recognized in each core by ROCKEVAL pyrolysis, [sup 13]C isotope signatures, shifts of increasing radiocarbon age with depth, shifts of increasing resistivity and density with depth, microfossil analysis, and the presence and type of shell material. Data collected in this project suggest the top of the Pleistocene in this onshore, fluvially-dominated section may not be the top of Substratum sands, but significantly higher in the section, as determined by the strongest positive reflection coefficient below the 10,000 year radiocarbon datum. This satisfies the criterion that this operational boundary be mappable and chronostratigraphic. Additionally, the presence of two growth faults in the northern part of the study area may have acted as sites for preferential thickening of the Holocene. Both reasons stated above profoundly influence the modeling of Holocene thickness and consolidation settlement potential, critical for understanding subsurface controls on wetland loss.

• OSTI ID: 5932313
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AQUATIC ECOSYSTEMS
BOREHOLES
CAVITIES
CENOZOIC ERA
DEVELOPED COUNTRIES
DRILL CORES
ECOSYSTEMS
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGIC SURVEYS
GEOLOGY
GROUND SUBSIDENCE
LOUISIANA
NORTH AMERICA
QUATERNARY PERIOD
SEDIMENTARY BASINS
STRATIGRAPHY
SURVEYS
USA
WELL LOGGING
WETLANDS