Distribution of Methane Plumes on Cascadia Margin and Implications for the Landward Limit of Methane Hydrate Stability
Distribution of Methane Plumes on Cascadia Margin and Implications for the Landward Limit of Methane Hydrate Stability
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卡斯卡迪亚边缘甲烷羽流的分布及其对甲烷水合物稳定性向陆极限的影响
DOI：
10.3389/feart.2021.531714
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发表时间：
2021
影响因子：
6.7
通讯作者：
L. Gee
中科院分区：
文献类型：
--
作者：
S. Merle;R. Embley;H. Johnson;T. Lau;B. Phrampus;N. Raineault;L. Gee
在美国卡斯卡迪亚边缘发现了近3500个甲烷气泡流，聚集在1300多个甲烷排放点，这些数据来自存档的公开数据和2011、2016-2018年使用共同注册的海底和水柱数据的专用多波束调查。在这项研究中，新的多波束声纳测量系统地绘制了美国卡斯卡迪亚边缘近40%的区域，从北部的胡安德富卡海峡延伸到南部的门多西诺断裂带，并以海岸和增量棱镜的底部为东西边界。气泡发射点的频率-深度直方图在500米等压线上有一个主要的峰值，该等压线沿俄勒冈州和华盛顿州附近的卡斯卡迪亚边缘的大部分横向延伸。与已发表的模拟海底反射体(BSR)分布的地震资料对比，模拟海底反射体(BSR)是甲烷水合物(固相)与下方游离气相之间的声阻抗边界，将甲烷水合物稳定带(FEMHS)羽状边缘的上端与新发现的俄勒冈州和华盛顿州附近的气泡发射点进行了关联。加州北部的卡斯卡迪亚边缘是BSR的终点，FEMHS的终点是大海，那里以500米等深线为中心的站点较少，尽管那里的数据更加有限。我们认为，在500m等深线附近观察到的气泡发射点的峰值是自由气体从BSR上坡下方的固相向FEMHS终止区迁移的结果，并建议这一边界将有助于监测可能与海洋变暖有关的甲烷释放速率的变化。
Nearly 3,500 methane bubble streams, clustered into more than 1,300 methane emission sites, have been identified along the US Cascadia margin, derived both from archived published data and 2011, 2016–2018 dedicated multibeam surveys using co-registered seafloor and water column data. In this study, new multibeam sonar surveys systematically mapped nearly 40% of the US Cascadia margin, extending from the Strait of Juan de Fuca in the north to the Mendocino fracture zone in the south, and bounded East–West by the coast and the base of the accretionary prism. The frequency-depth histogram of the bubble emission sites has a dominant peak at the 500 m isobar, which extends laterally along much of the Cascadia margin off Oregon and Washington. Comparisons with published seismic data on the distribution of bottom simulating reflectors (BSR), which is the acoustic impedance boundary between methane hydrate (solid phase) and free gas phase below, correlates the bottom simulating reflectors upward termination of the feather edge of methane hydrate stability (FEMHS) zone and the newly identified bubble emission sites off Oregon and Washington. The Cascadia margin off northern California, where the BSR ends seaward of the FEMHS, has fewer sites centered on the 500 m isobaths, although data are more limited there. We propose that the peak in bubble emission sites observed near the 500 m isobath results from migration of free gas from beneath the solid phase of the BSR upslope to the FEMHS termination zone, and suggest that this boundary will be useful to monitor for a change in methane release rate potentially related to a warming ocean.
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东北太平洋甲烷渗漏生物群落的异质性
DOI：
10.1016/j.dsr2.2017.10.016
发表时间：
2018
期刊：
Topical studies in oceanography
影响因子：
--
作者：
Seabrook, S.
通讯作者：
Seabrook, S.
影响因子：
3.6
作者：
Graves, Carolyn A.;Steinle, Lea;James, Rachael H.
通讯作者：
James, Rachael H.
影响因子：
4.9
作者：
Ciais, P.;Dolman, A. J.;Zehner, C.
通讯作者：
Zehner, C.
影响因子：
5
作者：
Graves, Carolyn A.;James, Rachael H.;Connelly, Douglas P.
通讯作者：
Connelly, Douglas P.
影响因子：
5.2
作者：
Biastoch, A.;Treude, T.;Wallmann, K.
通讯作者：
Wallmann, K.