Methane sources feeding cold seeps on the shelf and upper continental slope off central Oregon, USA
Methane sources feeding cold seeps on the shelf and upper continental slope off central Oregon, USA
复制标题
美国俄勒冈州中部附近的陆架和上大陆坡上的冷泉的甲烷来源
DOI：
--
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
K. Heeschen
中科院分区：
文献类型：
--
作者：
M. Torres;R. Embley;S. Merle;A. Tréhu;R. W. Collier;E. Suess;K. Heeschen
我们报告了沿着俄勒冈州从43°50′N到44°18′N的100-600 m区域的水深测绘和遥控潜水器调查。我们根据现有的地球物理数据、已发表的大地构造模型以及44°30′N至45°00′N之间流体喷发和碳酸盐沉积的类似观测结果解释了我们的结果。甲烷渗漏是由一个年轻的棱镜并列，其中甲烷是由细菌活动产生的，其释放是由气体水合物动力学调制，对旧的序列，作为一个来源的产热烃，在货架上发泄。我们假设，一个埋藏的脊与锡莱茨地体的碰撞结果在隆起的天然气水合物轴承沉积物在即将到来的板块和由此产生的压力降低导致天然气水合物的分解和甲烷exolution，这反过来，可能会促进边坡破坏。释放的甲烷氧化导致碳酸盐沉淀，这在沿着550 ± 60 m海底走廊的图像中表现为高后向散射。
We report on a bathymetric mapping and remotely operated vehicle surveys along the 100–600 m region offshore Oregon from 43°50′N to 44°18′N. We interpret our results in light of available geophysical data, published geotectonic models, and analogous observations of fluid venting and carbonate deposition from 44°30′N to 45°00′N. The methane seepage is defined by juxtaposition of a young prism, where methane is generated by bacterial activity and its release is modulated by gas hydrate dynamics, against older sequences that serve as a source of thermogenic hydrocarbons that vent in the shelf. We hypothesize that collision of a buried ridge with the Siletz Terrane results in uplift of gas hydrate bearing sediments in the oncoming plate and that the resulting decrease in pressure leads to gas hydrate dissociation and methane exolution, which, in turn, may facilitate slope failure. Oxidation of the released methane results in precipitation of carbonates that are imaged as high backscatter along a 550 ± 60 m benthic corridor.