Gas hydrate dissociation off Svalbard induced by isostatic rebound rather than global warming.
Gas hydrate dissociation off Svalbard induced by isostatic rebound rather than global warming.
复制标题
DOI：
10.1038/s41467-017-02550-9
复制
发表时间：
2018-01-08
影响因子：
16.6
通讯作者：
Bohrmann G
中科院分区：
文献类型：
--
作者：
Wallmann K;Riedel M;Hong WL;Patton H;Hubbard A;Pape T;Hsu CW;Schmidt C;Johnson JE;Torres ME;Andreassen K;Berndt C;Bohrmann G
从西斯瓦尔巴群岛的上大陆斜坡的甲烷渗漏以前被归因于天然气水合物的离解引起的环境底部沃茨的人为变暖。在这里，我们表明，沉积物岩心钻探王子卡尔斯前陆含有淡水分解水合物。然而，我们的模拟表明，所观察到的孔隙水淡化开始约8万年BP时，均衡抬升的速度超过海平面上升。由此产生的局部变浅和流体静压力的降低迫使天然气水合物分解和溶解的氯化物消耗与我们的地球化学分析一致。因此，我们认为水合物分解是由冰后期均衡反弹而不是人为变暖引发的。此外，我们表明，甲烷通量从解离水合物是远远小于目前的甲烷渗漏率，这意味着天然气水合物不是一个主要的来源，甲烷的海洋，而是作为一个动态密封，调节甲烷释放从深层地质储层。陆坡甲烷渗漏是由于人为活动引起的底层水变暖引起的天然气水合物分解。在这里，作者表明，水合物分解人类世之前，当均衡反弹引起的北极冰盖冰川消退超过海平面上升。
Methane seepage from the upper continental slopes of Western Svalbard has previously been attributed to gas hydrate dissociation induced by anthropogenic warming of ambient bottom waters. Here we show that sediment cores drilled off Prins Karls Foreland contain freshwater from dissociating hydrates. However, our modeling indicates that the observed pore water freshening began around 8 ka BP when the rate of isostatic uplift outpaced eustatic sea-level rise. The resultant local shallowing and lowering of hydrostatic pressure forced gas hydrate dissociation and dissolved chloride depletions consistent with our geochemical analysis. Hence, we propose that hydrate dissociation was triggered by postglacial isostatic rebound rather than anthropogenic warming. Furthermore, we show that methane fluxes from dissociating hydrates were considerably smaller than present methane seepage rates implying that gas hydrates were not a major source of methane to the oceans, but rather acted as a dynamic seal, regulating methane release from deep geological reservoirs. Methane seepage from continental slopes has been attributed to gas hydrate dissociation induced by anthropogenic bottom water warming. Here, the authors show that hydrates dissociated before the Anthropocene when the isostatic rebound induced by deglaciation of the Arctic ice sheet outpaced eustatic sea-level rise.
登录
查看更多内容
影响因子：
2.2
作者：
Hughes, Anna L. C.;Gyllencreutz, Richard;Svendsen, John Inge
通讯作者：
Svendsen, John Inge
影响因子：
4
作者：
Auriac, A.;Whitehouse, P. L.;Hubbard, A.
通讯作者：
Hubbard, A.
影响因子：
5.2
作者：
Darnell, K. N.;Flemings, P. B.
通讯作者：
Flemings, P. B.
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：
3.4
作者：
BLATTER, H
通讯作者：
BLATTER, H