Ontong Java Plateau eruption as a trigger for the early Aptian oceanic anoxic event
- Maria Luisa G. Tejada1,2,
- Katsuhiko Suzuki2,
- Junichiro Kuroda2,
- Rodolfo Coccioni3,
- John J. Mahoney4,
- Naohiko Ohkouchi2,
- Tatsuhiko Sakamoto2 and
- Yoshiyuki Tatsumi2
- 1National Institute of Geological Sciences (NIGS), University of the Philippines, Quezon City, 1101, Philippines
- 2Institute for Research on Earth Evolution (IFREE), Japan Agency for Marine-Earth Science and Technology, Yokosuka, 237-0061, Japan
- 3Dipartimento di Scienze dell'Uomo, dell'Ambiente e della Natura, Università di Urbino, 61029 Urbino, Italy
- 4School of Ocean and Earth Science Technology (SOEST), University of Hawaii, Honolulu, Hawaii 96822, USA
Abstract
The Early Cretaceous Ontong Java Plateau was emplaced at almost the same time as marine biotic changes that culminated in oceanic anoxic event 1 (OAE1a). A causative link between these events has been suggested, but direct evidence has been lacking until now. New Os isotope measurements across the Lower Aptian “Selli Level” black shale deposited during OAE1a in central Italy reveal two negative excursions in marine 187Os/188Os ratios within a period of 2 Ma starting above the Barremian-Aptian boundary and ending just above the Selli Level horizon, suggesting an order-of-magnitude increase in the global flux of unradiogenic Os. The results are consistent with early and major phases of eruption of the Ontong Java Plateau. The latter phase is estimated to have been as short as ~1 Ma and may have induced widespread oceanic stratification that triggered OAE1a.
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- Received 9 January 2009.
- Revision received 6 April 2009.
- Accepted 3 May 2009.
