A detection of Milankovitch frequencies in global volcanic activity
نویسندگان
چکیده
A rigorous detection of Milankovitch periodicities in volcanic output across the PleistoceneHolocene ice age has remained elusive. We report on a spectral analysis of a large number of well-preserved ash plume deposits recorded in marine sediments along the Pacifi c Ring of Fire. Our analysis yields a statistically signifi cant detection of a spectral peak at the obliquity period. We propose that this variability in volcanic activity results from crustal stress changes associated with ice age mass redistribution. In particular, increased volcanism lags behind the highest rate of increasing eustatic sea level (decreasing global ice volume) by 4.0 ± 3.6 k.y. and correlates with numerical predictions of stress changes at volcanically active sites. These results support the presence of a causal link between variations in ice age climate, continental stress fi eld, and volcanism. GEOLOGY, February 2013; v. 41; no. 2; p. 227–230; Data Repository item 2013055 | doi:10.1130/G33419.1 | Published online 30 November 2012 © 2012 eological Society of America. For permission to copy, contact Copyright Permissions, GSA, or [email protected]. 1GSA Data Repository item 2013055, data, additional fi gures explaining the methods, and an extended error analysis of the data set and statistics, is available online at www.geosociety.org/pubs/ft2013.htm, or on request from [email protected] or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301, USA. Bering Sea Gulf of Alaska Sea of Japan Sea of Okhotsk Asia North America
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