Organoclastic sulfate reduction in deep-buried sediments: Evidence from authigenic carbonates of the Gulf of Mexico
Organoclastic sulfate reduction in deep-buried sediments: Evidence from authigenic carbonates of the Gulf of Mexico
复制标题
深埋沉积物中有机碎屑硫酸盐的还原：来自墨西哥湾自生碳酸盐的证据
DOI：
10.1016/j.chemgeo.2022.121094
复制
发表时间：
2022-09
期刊：
影响因子：
3.9
通讯作者：
Duofu Chen
中科院分区：
文献类型：
--
作者：
Huiwen Huang;Dong Feng;Yangrui Guo;Xudong Wang;Shanggui Gong;Jörn Peckmann;Wen Yan;Harry H. Roberts;Duofu Chen
深埋海洋沉积物中有机质的命运决定了油气藏的形成，塑造了深层生物圈，并影响着全球碳循环。一些地球化学过程，如硅酸盐风化，铁和锰（氢）氧化物还原，硫酸盐还原影响埋藏沉积物中有机质的矿化。然而，关于深层有机硫酸盐还原的信息很少，所涉及的地球化学过程在很大程度上是未知的。在这里，自生碳酸盐回收船浅滩块296（SS 296）的墨西哥湾，所有占主导地位的低镁方解石，进行了研究，以约束有机硫酸盐还原深埋沉积物。SS 296碳酸盐岩以前被认为是深部成因，并通过盐底辟作用向上搬运。样品3110 R1和3110 R2中存在锥中锥结构，以及0.48%至0.58%的镜质体反射率值，表明碳酸盐岩形成于相对较深的埋藏处。同样地，聚集同位素测温法得到样品3110 R1的地层温度为45 °C至53 °C，样品3110 R2的地层温度为60 °C，样品3110 R3的地层温度为11 °C至37 °C。尽管地层深度较大，但样品3110 R1和3110 R2的温度仍处于微生物硫酸盐还原的温度范围内，反映地层深度在1 km至2.7 km之间。草莓状黄铁矿的存在及其相对较低的δ 34 S值（−27.8‰至+11.5‰）与碳酸盐沉淀过程中微生物硫酸盐还原的发生相一致。碳酸盐岩的碳同位素组成（δ 13 C：−16.6‰ ~ −8.9‰）和包裹有机质（δ 13 C org：−26.8‰ ~ −20.5‰）表明有机质是碳酸盐矿物的主要碳源。这项研究证实，微生物硫酸盐还原发生在深埋沉积物中，驱动有机质的降解。我们的研究结果表明，有机硫酸盐还原可能在深层沉积环境中很常见，控制着深层地下环境中有机物质的命运，并影响着全球碳循环。·在墨西哥湾SS 296站点采样的碳酸盐形成于约60 °C。·碳酸盐中黄铁矿δ 34 S值的变化反映了硫酸盐还原的存在。碳酸盐岩的主要碳源是沉积有机质而不是烃类。·碳酸盐反映了深埋沉积物中微生物介导的有机硫酸盐还原。
The fate of organic matter in deep-buried marine sediments determines the formation of hydrocarbon reservoirs, shapes the deep biosphere, and affects the global carbon cycle. Several geochemical processes such as silicate weathering, iron and manganese (hydr)oxide reduction, and sulfate reduction influence the remineralization of organic matter in buried sediments. However, little information on deep-seated organoclastic sulfate reduction is available and the involved geochemical processes are largely unknown. Here, authigenic carbonates recovered from Ship Shoal Block 296 (SS296) of the Gulf of Mexico, all dominated by low-magnesium calcite, were investigated to constrain organoclastic sulfate reduction in deep-buried sediments. The SS296 carbonates had been previously suggested to be of a deep origin and transported upward by salt diapirism. The presence of cone-in-cone textures in samples 3110R1 and 3110R2, as well as vitrinite reflectance values of 0.48% to 0.58%, indicate carbonate formation at a relatively deep burial. Likewise, clumped isotope thermometry yielded formation temperatures from 45 °C to 53 °C for sample 3110R1, 60 °C for sample 3110R2, and 11 °C to 37 °C for sample 3110R3. In spite of formation at greater depth, the temperatures of samples 3110R1 and 3110R2 are still within the temperature range of microbial sulfate reduction, reflecting formation depths between 1 km and 2.7 km. The presence of framboidal pyrite and its relatively low δ 34 S values (−27.8‰ to +11.5‰) agree with the occurrence of microbial sulfate reduction during carbonate precipitation. The carbon isotopic composition of the carbonates (δ 13 C: −16.6‰ to −8.9‰) and enclosed organic matter (δ 13 C org : −26.8‰ to −20.5‰) suggests that organic matter is the dominant carbon source of carbonate minerals. This study confirms that microbial sulfate reduction occurs in deep-buried sediments, driving the degradation of organic matter. Our findings suggest that organoclastic sulfate reduction might be common in deep-seated sedimentary environments, controlling the fate of organic matter in deep subsurface environments and affecting the global carbon cycle. • Carbonates sampled at site SS296 in the Gulf of Mexico formed at about 60 °C. • Variable δ 34 S values of pyrite enclosed in carbonates reflect the presence of sulfate reduction. • The main carbon source of carbonates was sedimentary organic matter rather than hydrocarbons. • Carbonates reflect microbial-mediated organoclastic sulfate reduction in deep-buried sediments.
登录
查看更多内容
DOI：
10.1007/bf02547004
发表时间：
1994-07
期刊：
Journal of Thermal Analysis
影响因子：
--
作者：
T. P. Goldstein;Z. Aizenshtat
通讯作者：
T. P. Goldstein;Z. Aizenshtat
DOI：
10.1007/bfb0012103
发表时间：
1986
期刊：
--
影响因子：
--
作者：
C. E. Barker;M. Pawlewicz
通讯作者：
C. E. Barker;M. Pawlewicz
影响因子：
5.8
作者：
A. Draut;P. Clift
通讯作者：
A. Draut;P. Clift
影响因子：
5
作者：
J. Rosenbaum;S. Sheppard
通讯作者：
J. Rosenbaum;S. Sheppard
影响因子：
3.5
作者：
S. Nagihara;M. Smith
通讯作者：
S. Nagihara;M. Smith