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EGG-01 General contributions to environmental geology
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Geochemistry and petrography of box-core sediments from a methane seep setting in the Strait of Sicily, central Mediterranean
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Marianna Cangemi, University of Palermo (Italy)
Rossella Di Leonardo, University of Palermo (Italy)
Adriana Bellanca, University of Palermo (Italy)
Rodolfo Neri, University of Palermo (Italy)
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Recent morpho-acustic surveys have revealed a mud volcano area on the Hiblean-Malta Plateau (Strait of Sicily, Southern Italy) sited at water depths between -70 and -170 m along faults adjacent to the Scicli fracture zone. The acoustic data suggest gas rising from the sediments of the vulcano structures. Five box-cores have been collected in this area, during two oceanographic cruises carried out aboard the R/V "UNIVERSITATIS" in February and July 2007. Authigenic carbonate associated with the studied sediments exhibits large 13C depletion that indicates methane as a major source for the carbonate carbon. Scanning electron microscope observations of carbonate crusts showed filamentous structures and globular forms resembling those commonly recognized in methane seep settings and generally referred to bacterial activity. Bulk mineralogy and major element geochemistry of box-core sediments are comparable with those of sediments from other areas in the Strait of Sicily. Some trace metals show high concentrations if compared with background levels in the Strait of Sicily, probably due to association with sulphides. Notably As is enriched by more 4 times with respect to central Mediterranean coastal sediments, which are suspected to have experienced anthropogenic influence.
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