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Beginning the Search for Offshore Oil Seeps Near Point Conception, California By Keith Kvenvolden and Tom Lorenson September 2001 in this issue:  previous story | next story Location map: Locations of beaches (indicated in red) and oil-production platforms (blue rectangles). In collaboration with the Minerals Management Service (MMS), a field study has been initiated to assess the interrelations among oil seeps, tarballs, and produced crude oils in a coastal region of southern California from Point Arguello to Point Conception (see map). The first sampling trip was undertaken July 23rd to 26th by the USGS team of Keith Kvenvolden, Tom Lorenson, Bob Rosenbauer, and Fran Hostettler (all CMGP), accompanied by Mary Elaine Dunaway of MMS and Christy Roe and Maya George of the University of California, Santa Cruz. The field party visited three beaches: Boathouse and Jalama within the study area, and Casmalia north of the study area. Photograph quadrats were established at rocky intertidal areas at Boathouse and Jalama Beaches for repeated sampling of tarballs at three-month intervals during the next three years. On the sandy beaches at Boathouse and Jalama, transects were run parallel and perpendicular to the shoreline; 108 tarballs were recovered from these transects. Casmalia Beach was very clean; only seven tarballs were observed. click on any of the three images below to view a larger version Casmalia Beach with Point Sal in the distance. Setting up photoquadrats at Boathouse Beach. On oil-production platform Harvest, from left to right: Fran Hostettler, Keith Kvenvolden, Mary Elaine Dunaway (MMS), and Tom Lorenson. Seventeen tarballs were selected from all the beaches for geochemical analyses. Weight of the 17 tarballs was approximately half a kilogram; another three kilograms of tar were removed from the beaches and discarded. Thirteen samples of production oil were obtained (using helicopter support) from Hidalgo, Hermosa, and Harvest, three oil-production platforms in the offshore portion of the study area. This initial sampling effort provides material to develop geochemical criteria for differentiating produced crude oil from crude oil released from natural seepage, and to assess the sources of tarballs on the California coast. in this issue:  previous story | next story

September 2001 Mailing List: Sign up to receive monthly email updates: in this issue: cover story: Moloka'i Coral Reef Monitoring North Carolina Cruises California Offshore Oil Seeps Training FWS in Geologic Processes of Coastal Ecosystems MRIB to Host Digital Library of Gulf of Maine Coastal Summit Coastal Issues at GSA Dust Transport Gulf of Mexico Integrated Science Geographical Honor Society—Larry Handley Quenton Smith-Costello: SEPAC NWRC Seminars September Publications List

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