Carpinteria Salt Marsh Reserve

03 Feb, 12 AM - 09 Feb, 09 AM

A team of scientists sponsored by the US Geological Survey conducted research at Carpinteria Salt Marsh Reserve in February, 2008 to establish a record of paleotsunami deposits at Carpinteria. During this investigation, 59 gouge cores were logged and 8 russian cores (6 cm X 50 cm D-tube samples) were taken. Paleotsunami deposits are most easily identified in cores when they occur as sand layers that overlie the peat and mud characteristic of normal marsh sedimentation. Results of this research indicated 4 areas that had candidate tsunami deposits. While deposits from these areas were consistent with tsunami deposition, some characteristics of the deposits were also consistent with channel deposition, making the determination of deposit origin difficult. Also, in the initial survey, material suitable for dating was scarce, providing little age control for the deposits. The proposed research consists of 4 objectives that will address our needs for additional data and help to clarify the origin of the candidate sand layers and the tsunami record at Carpinteria Salt Marsh. Channel Migration: More work at Carpinteria needs to be done to understand how deposits from a migrating channel would look in a 30 mm core to compare with results from the previous field work. Existing channels need to be examined for evidence of channel migration. A transect across an existing channel, perpendicular to the channel, will document the sedimentary signature of channel deposition and migration. Sediment samples will be taken for further laboratory examination. Reexamine and sample at core sites where candidate tsunami deposits were previously identified: Core at locations of previously identified deposits using 30 mm and 60 mm barrels. Collect samples for microfaunal and radiocarbon analyses using Russian corer and/or 60 mm barrel. Samples will be used to constrain the age of the deposits and sedimentation rates. At least one core site from each of the 4 groups should be reexamined and additional cores may be taken within group areas. Transect along west side of marsh: The west side of the marsh was underrepresented in cores from the previous study but is farthest from the clearly engineered channels of Franklin and Santa Monica Creeks. The dominance of mud below 0.5 meters in most of the cores taken on the previous study suggests that the present marsh is young. Marsh surface may have been restricted to fringing marshes surrounding open water, mudflat, and estuarine environments. A shore-normal transect along this section of the marsh will increase the grid coverage of the previous survey and may have a good chance of finding peat from these fringing marshes. Peat from a fringing marsh surface may be more likely to preserve a record of tsunami deposition. The core taken closest to this section in the previous study was among the deepest recovered (283 m), suggesting a longer record may be preserved here than elsewhere in the marsh. Other coring objectives: One of the goals of the initial fieldwork was to establish a tsunami chronology at Carpinteria. However, identified candidate deposits were all at depth less than one meter. Other sand layers were found at deeper depths, but data was insufficient to establish their origin. A fourth objective is to relocate and trace isolated deeper sand layers already found in existing cores to map their extent and to find other areas where deeper cores may establish a tsunami chronology. Planned use and publication of results: Following the survey, the results will be combined with our results from the previous fieldwork and published either as a peer-reviewed journal article or a USGS open file report (or both). The USGS is currently collaborating with the California Geological Survey and Humboldt State University on a survey of tsunami deposits along the California coast. Results from this study may also be used in this study and field team members for the proposed fieldwork may consist of personnel from these institutions. Preferred dates for field work: Field work will require 2-5 days in the field. Tides favorable for this field work occur from January 5-10 and from January 18-23. I have applied for January 5-10. If field team members are not avialabile on the earlier dates, I may amend the application for fieldwork January 18-23. Field team: The field team will consist of 4-8 scientists. If a larger field team is present, the team will split into 2 groups to minimize impact on the marsh and to more effectively complete the objectives. Robert Peters and Bruce Richmond of the USGS are committed to being on the field team and will direct the research. Other potential team members who may be present for all or part of the fieldwork are listed on the application.

Visit #26907 @Carpinteria Salt Marsh Reserve

Approved

Under Project # 8843 | Research

Carpinteria Marsh Tsunami Deposit Investigation

research_scientist - US Geological Survey

Reservation Members(s)

Robert Peters Feb 3 - 9, 2012 (7 days)
Group of 7 Research Scientist/Post Doc Feb 3 - 9, 2012 (7 days)

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Day Use Only 8 Feb 3 - 9, 2012