中文摘要：

甲烷渗漏活动及其甲烷厌氧氧化（AOM）在自生碳酸盐岩沉淀的同时,也通过影响孔隙水溶解无机碳（DIC）进而影响着周围环境中底栖有孔虫,以往的文章鲜有报道二者的耦合响应。研究开展了综合大洋钻探计划IODP 311航次两个钻孔（1328和1329）中获得的自生碳酸盐岩和底栖有孔虫（Uvigerina peregrina）同位素研究,发现晚更新世以来多个层位获得的自生碳酸盐岩和底栖有孔虫的稳定碳同位素变化趋势均呈现一致的负偏碳同位素特征,但是,同层位的自生碳酸盐岩碳同位素负偏程度要比底栖有孔虫大一个数量级。自生碳酸盐岩与底栖有孔虫碳同位素变化趋势的一致性表明二者对于甲烷渗漏作用有较好的共同响应。AOM作用对孔隙水中溶解无机碳（DIC）的影响可在重碳酸氢根通过局部环境的过饱和沉淀自生碳酸盐岩的同时,也能部分参与底栖有孔虫的成壳,两者在成因方面是耦合的。综合结合自生碳酸盐岩和底栖有孔虫的碳同位素特征可以避免单一载体易受后期成岩改造影响而掩盖甲烷渗漏活动的识别。

英文摘要：

Methane seeps play a significant role in the evolution of pore water dissolved inorganic carbon（DIC）via anaerobic oxidation of methane（AOM）,which could make authigenic carbonates precipitated and influence the benthic foraminifera living near seep environments.Two independent proxies involving the carbon isotopic composition of authigenic carbonates and benthic foraminifera（Uvigerina peregrina）were studied to verify the potential relationship between authigenic carbonates and foraminifera as co-indicators of episodic methane seeps during late Pleistocene and Holocene in the northern Cascadia margin＇s gas hydrate geo-system.Both authigenic carbonates and benthic foraminifera exhibit episodic negative carbon isotope excursions during the past 1.6Ma at site U1328 and 8.5Ma at site U1329.The carbon isotope excursions of benthic foraminifera coincide with those of authigenic carbonates at several methane seep stages,even though a profound carbon isotopic disequilibrium exists between the authigenic carbonates and benthic foraminifera.Methane seep-related AOM favors authigenic carbonate precipitation and also leaves imprints on the DIC that could be recorded by the calcification of benthic foraminifera.The carbon isotopic coincidence between authigenic carbonates and benthic foraminifera demonstrates that two proxies could record the same methane seep events.We combine the benthic foraminifera with authigenic minerals to reveal that the methane seep events could preclude the post-depositional alterations of the authigenic carbonates and delineate the specific history of episodic methane seep events.