Title| Summary|Strategy|Impacts/Products|Collaborators/Clients|Task 1|Task 2 |Task 3|Task 4|Task 5|Task 6|Task 7

GEOLOGIC DIVISION CONTINUING PROJECT WORK PLAN - FL 2001

Task: 5
Task Leader: Kindinger, Jack L.
600 4th Street South
St. Petersburg, FL 33701
Phone: (727)803-8747
Fax: (727)803-2030

Title: Geologic Framework, Sediment Characterization, Wetland Change and Geologic Database

Coastal and Marine Geology Programs

The storage and delivery of environmentally relevant contaminants in both the lower Atchafalaya and Mississippi River systems are of public concern to the environmental health of the deltas and coastal Gulf of Mexico. To understand and assess riverine sediment-hosted pollutant transport it is necessary to have an accurate description of sediment distribution patterns within the systems. Deltas basically consist of a sandy framework infilled with finer-grained sediment. Fine-grained sediments are fluvially transported into the deltaic complex and dispersed as a buoyant plume, density underflows as part of the river bedload, or deposited as overbank material during flood stages of the river, on the floodplain, in interdistributary bays and wetlands, and crevasse splays. Once depositional patterns are identified and pollutant pathways established, we can reconstruct and evaluate a complete historical inventory of these pollutants in this heavily industrialized corridor. The fate of sediment-hosted contaminants in the lower river will also be assessed as a potential input to wetlands.

Work to be undertaken during the proposal year and a description of the methods and procedures:

As funds become available the following subtasks will be undertaken. The investigations would measure, map and monitor depositional patterns of these complex delta systems. By coordinated effort of each of the tasks in this project we hope to characterize the pollutant pathways and storage within the systems.

1. Geologic Framework: Initiate inventory of existing data. Analysis and interpretation of geophysical and vibracore data to decipher the geologic structure, stratigraphy, and detailed sedimentary history and bedforms associated with the Holocene to modern distal delta (birds foot) and river channels. We would rely on Tulane (Allison and Cokely) to describe river- sediment characteristics. CMPG would focus on deltaic processes.
   
2. Sediment Characterization: Gather existing sediment and geochemical data; sample and analyze sediment samples and provide rates of sedimentation across the delta and river. Sediment samples and vibracores will be used to determine sediment characterization. From surface sediments scientists can also locate present-day accumulation of contamination.
   
3. Wetland Change: To document the role of emergent wetlands within the Balize Delta in trapping fine sediments, and thus their role in the fate of fine-sediment associated contaminants, a series of surficial accumulation stations will be established. Each station will consist of a sediment-erosion-table (SET) base pipe, with sampling platform and feldspar markers or sedimentation plates. These techniques allow identification of the relative roles of surface vs. shallow subsurface processes in controlling marsh surface elevation. The amount of mineral vs. organic sediment accumulating on the marsh surface will be determined by laboratory analyses of samples from cryogenic cores. Representative sites that characterize the variability of the river mouth landscape should be selected. At each of these sites an SET should be installed and the shallow geologic framework delineated. Vibracores combined with radiometric dating should be conducted. The changes in the river mouth landscape should be documented using historical T-sheets and H-sheets combined with aerial photography. Measurements will be obtained seasonally to determine variations in accumulation among periods of high-river discharge, low river discharge, and winter cold front activity.
   
4. Geologic and spatial database: Use existing/constructed layers, archival maps and digitized photographs to construct a localized database. A collaborative effort between NMD, Mid-Continent Mapping Center (MCMC) and GD, Center for Coastal Geology (CCG) would provide support for the collection/generation of selected base data layers from national data sets and Bureau assets for studies in selected areas of the Gulf Coast. Collaboration will focus on the application of these national data sets and assets with the integration of newer scientific information from the CCG. These applications will contribute to the support of CCG programs by providing basic data from which to begin the research as well as better visualization and presentation tools for use with the research results. The collaboration will provide for the potential to enhance and maintain national data sets of the NMD through increased awareness of the national data sets available from the NMD, identification and refinement of data characteristics for a non-traditional data.
   

Planned Outreach:

Summarize results in Fact Sheets and on website. Meet with representatives of Federal and State agencies in Louisiana to present progress reports.

Publications delivered/completed for this Task:

Publications planned for this task, to be submitted for publication in current or future fiscal years.

• Kindinger et al, 2002, Geologic framework of the modern Mississippi and Atchafalaya deltas.
• Allison et al. (Tulane COOP)), 2002, Ephemeral deposits in the lower reaches of the Mississippi and Atchafalaya Rivers.

Geographic area of task:

United States, Gulf Coastal States, LA
Polygon Lat/Long: 29°/88°, 29°/92°, 30°/88°, 30°/92°

Accomplishments

Current year nonpublication accomplishments and outcomes:
Successful coring operations and geophyscial surveys in the two deltas systems. During the spring high-flow stage of the Mississippi and Atchafalaya Rivers 2 seismic surveys (65 line-km) and 13 vibracores were collected in Mississippi and Atchafalaya deltas. Also 2 side-scan sonar surveys were conducted of the Mississippi River bottom along portions of two distributaries. These data are presently being analysized.

Highlights - summary of the most significant outcome:
Productive coop with Tulane has provided high resolution bottom imagery and samples of ephemeral deposits in the lower rivers. We are investigating the geochemical character of these seasonal deposits and will be able to derive flux estimates for this important additional source term. The Tulane coop has enabled integration of our project to two concurrent NSF funded research efforts.

New Directions or Major Changes for Proposal Year:
Kindinger has requested the addition of John Chin, an expert sedimentologist. He would be in charge of USGS framework efforts.

Title|Summary|Strategy|Impacts/Products|Collaborators/Clients|Task 1|Task 2 |Task 3|Task 4|Task 5|Task 6|Task 7