CAJ | 학술논문

在海底冷泉活动区渗漏甲烷被细菌缺氧氧化为 HCO3?,产生碳酸盐岩沉淀,同时消耗沉积物孔隙水中的硫酸根离子,从而改变沉积环境的氧化还原条件.墨西哥湾和刚果扇的现代冷泉碳酸盐岩及摩洛哥 Hollard Mound中泥盆统和意大利Marmorito中新统冷泉碳酸盐岩的泥晶和亮晶碳酸盐矿物的稀土元素(rare earth element, REE)总量(ΣREE)质量分数变化范围较大(0.3×10–6—43.7×10–6),泥晶的ΣREE 高于亮晶碳酸盐矿物.稀土元素页岩标准化配分模式具有不同的Ce异常特征,即使在同一地点采集的样品也表现出不同的Ce异常,显示了冷泉活动区海底除目前认识到的还原环境外,至少存在局部和短暂的氧化环境.氧化还原条件的改变可能与冷泉流体流动速率变化有关,或与甲烷缺氧氧化伴生的反硝化作用产生的氧有关.
재해저랭천활동구삼루갑완피세균결양양화위 HCO3?,산생탄산염암침정,동시소모침적물공극수중적류산근리자,종이개변침적배경적양화환원조건.묵서가만화강과선적현대랭천탄산염암급마락가 Hollard Mound중니분통화의대리Marmorito중신통랭천탄산염암적니정화량정탄산염광물적희토원소(rare earth element, REE)총량(ΣREE)질량분수변화범위교대(0.3×10–6—43.7×10–6),니정적ΣREE 고우량정탄산염광물.희토원소혈암표준화배분모식구유불동적Ce이상특정,즉사재동일지점채집적양품야표현출불동적Ce이상,현시료랭천활동구해저제목전인식도적환원배경외,지소존재국부화단잠적양화배경.양화환원조건적개변가능여랭천류체류동속솔변화유관,혹여갑완결양양화반생적반초화작용산생적양유관.
At marine seeps, methane is microbially oxidized resulting in the precipitation of carbonate close to the seafloor. Methane oxidation leads to sulfate depletion in sediment pore water and induces change in redox conditions. Rare earth element (REE) patterns of authigenic carbonate phases from limestone collected from modern seeps of the Gulf of Mexico and the Congo Fan, as well as from two ancient hydrocarbon-seep localities, Hollard Mound (Middle Devonian) and Marmorito (Miocene), were investigated. The total REE content (ΣREE) of seep carbonates varies widely from 0.3×10?6 to 43.7×10?6, with a common trend that the ΣREE in microcrystalline phases is higher than that in sparite cement. The shale-normalized REE patterns of seep carbonates often show different Ce anomalies, even in the samples from the same site. These varied Ce anomalies suggested that the redox conditions of seep carbonates are variable and complex. Overall, our results show that oxic conditions are at least temporarily common in seep environment. The varied redox conditions might be related to the changes of flux of seep fluid or the denitrification associated with methane oxidation that produces oxygen.