Kennett JP, Cannariato KG, Hendy IL, Behl RJ
Geological Sciences and Marine Science Institute, University of California, Santa Barbara, CA 93106, USA. Department of Geological Sciences, California State University, Long Beach, CA 90840, USA.
Science. 2000 Apr 7;288(5463):128-33. doi: 10.1126/science.288.5463.128.
Large (about 5 per mil) millennial-scale benthic foraminiferal carbon isotopic oscillations in the Santa Barbara Basin during the last 60,000 years reflect widespread shoaling of sedimentary methane gradients and increased outgassing from gas hydrate dissociation during interstadials. Furthermore, several large, brief, negative excursions (up to -6 per mil) coinciding with smaller shifts (up to -3 per mil) in depth-stratified planktonic foraminiferal species indicate massive releases of methane from basin sediments. Gas hydrate stability was modulated by intermediate-water temperature changes induced by switches in thermohaline circulation. These oscillations were likely widespread along the California margin and elsewhere, affecting gas hydrate instability and contributing to millennial-scale atmospheric methane oscillations.
在过去6万年里，圣巴巴拉盆地出现了幅度较大（约千分之五）的千年尺度底栖有孔虫碳同位素振荡，这反映出沉积甲烷梯度普遍变浅，以及间冰期期间天然气水合物分解导致的气体排放增加。此外，几次幅度较大、持续时间短的负向偏移（高达千分之六），与深度分层的浮游有孔虫物种中幅度较小的偏移（高达千分之三）同时出现，表明盆地沉积物中有大量甲烷释放。热盐环流的转换引起中间层水温变化，进而调节了天然气水合物的稳定性。这些振荡可能在加利福尼亚边缘及其他地区广泛存在，影响天然气水合物的不稳定性，并导致千年尺度的大气甲烷振荡。
