海洋地质与第四纪地质2024，Vol.44Issue(6)：96-104,9.DOI:10.16562/j.cnki.0256-1492.2023100802
流体渗漏强度变化对烟囱状冷泉碳酸盐岩中铁和磷循环的影响
The impact of change in fluid seepage intensity on iron and phosphorus cycling in chimney-like seep carbonates
摘要
Abstract
During the formation of seep carbonates,variations in fluid seepage affect the biogeochemical processes that drive the cycling of various elements,such as carbon and sulfur.However,such an influence on iron(Fe)and phosphorus(P)cycling and related biogeochemical processes remains unclear.In this study,mineral compositions,carbon and sulfur geochemistry,Fe and P component were investigated on a cross section of a chimney-like seep carbonate sample collected from the Dongsha area of the South China Sea.Results reveal that the anaerobic oxidation of biogenic methane led to the formation of the extremely 13C-depleted authigenic carbonate rocks(δ13CVPDB＜-55.5‰),and the addition of enriched 18O fluids from the dissociation of gas hydrates results in abnormally high oxygen isotope composition(5.5‰-5.8‰)observed in the chimney carbonates.Combined with the dominant minerals with calcite in the outer layer of the chimney carbonates and aragonite in the inner layer,we inferred that the carbonates in the inner layer were formed at the later stage under stronger methane seepage condition.The most significant P-bearing mineral in the samples is authigenic phosphate(PAuth),and the highest content is in the inner layer of the chimney carbonates.Compared with the outer chimney sample,the inner layer has lower Fe oxide content,but higher Fe-bound P(PFe)content,indicating the formation of vivianite.Therefore,we believe that under a stronger seepage condition during the formation of seep carbonates,an enhanced intensity of methane seepage can affect the abundance of PAuth and PFe,which may favor the formation of vivianite and authigenic phosphates,thereby influencing Fe and P cycling in cold-seep environments.关键词
甲烷渗漏/磷组分/铁组分/磷循环/冷泉碳酸盐岩Key words
methane seepage/phosphorus component/iron component/phosphorus cycle/seep carbonate分类
海洋科学引用本文复制引用
高宇,刘春阳,胡钰,陈琳莹,梁前勇,冯东,陈多福..流体渗漏强度变化对烟囱状冷泉碳酸盐岩中铁和磷循环的影响[J].海洋地质与第四纪地质,2024,44(6):96-104,9.基金项目
国家自然科学基金面上项目"南海海马冷泉区硫化环境中蓝铁矿的形成机制及其对海洋磷循环的指示"(42472145) （42472145）
