Warming the fuel for the fire: Evidence for the thermal dissociation of methane hydrate during the Paleocene-Eocene thermal maximum

被引:3
作者
Thomas, DJ [1 ]
Zachos, JC
Bralower, TJ
Thomas, E
Bohaty, S
机构
[1] Univ N Carolina, Dept Geol Sci, Chapel Hill, NC 27599 USA
[2] Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA
[3] Wesleyan Univ, Dept Earth & Environm Sci, Middletown, CT 06549 USA
[4] Yale Univ, Ctr Study Global Change, New Haven, CT 06520 USA
[5] Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA
关键词
Paleocene-Eocene thermal maximum; stable isotopes; methane hydrates; paleoceanography;
D O I
10.1130/0091-7613(2002)030<1067:WTFFTF>2.0.CO;2
中图分类号
P5 [地质学];
学科分类号
0709 ; 081803 ;
摘要
Dramatic warming and upheaval of the carbon system at the end of the Paleocene Epoch have been linked to massive dissociation of sedimentary methane hydrate. However, testing the Paleocene-Eocene thermal maximum hydrate dissociation hypothesis has been hindered by the inability of available proxy records to resolve the initial sequence of events. The cause of the Paleocene-Eocene thermal maximum carbon isotope excursion remains speculative, primarily due to uncertainties in the timing and duration of the PaleoceneEocene thermal maximum. We present new high-resolution stable isotope records based on analyses of single planktonic and benthic foraminiferal shells from Ocean Drilling Program Site 690 (Weddell Sea, Southern Ocean), demonstrating that the initial carbon isotope excursion was geologically instantaneous and was preceded by a brief period of gradual surface-water warming. Both of these findings support the thermal dissociation of methane hydrate as the cause of the Paleocene-Eocene thermal maximum carbon isotope excursion. Furthermore, the data reveal that the methane-derived carbon was mixed from the surface ocean downward, suggesting that a significant fraction of the initial dissociated hydrate methane reached the atmosphere prior to oxidation.
引用
收藏
页码:1067 / 1070
页数:4
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