Carbon-sulfur signals of methane versus crude oil diagenetic decomposition and U-Th age relationships for authigenic carbonates from asphalt seeps, southern Gulf of Mexico

Akam, Sajjad; Lyons, Timothy W.; Coffin, Richard B.; McGee, David; Naehr, T. H.; Bates, Steven M; Clarkson, C. C.; Reese, Brandi Kiel

doi:10.1016/j.chemgeo.2021.120395

Cited by 3 publications

(1 citation statement)

References 166 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A pyrite based proxy offers insights into the evolution of fluid composition at seeps, which is critical because fluid composition governs microbial and metazoan ecology (Orcutt et al, 2010). The significance of distinguishing oilfrom methane-dominated seep systems has gained traction in recent years in the search for end member system identification (Smrzka et al, 2016;Akam et al, 2021;Krake et al, 2022), and reliable proxies are continuously being explored and refined.…”

Section: Introductionmentioning

confidence: 99%

Pyrite-based trace element fingerprints for methane and oil seepage

Smrzka,

Lin,

Monien

et al. 2024

Geochem. Persp. Let.

View full text Add to dashboard Cite

Pyrite forms at marine hydrocarbon seeps as the result of the microbial oxidation of methane, organic matter, and crude oil coupled to sulphate reduction. Redox sensitive and nutrient trace elements in pyrite may hold valuable information on present and past seepage events, the evolution of fluid composition, as well as the presence of heavy hydrocarbon compounds from crude oil. This study uses the trace element compositions of pyrite that formed at methane seeps and crude oil-dominated seeps to constrain element mobilities during the sulphate reduction processes, and examine the degree to which specific trace elements are captured by pyrite. Pyrite forming at oil seeps shows high Mn/Fe ratios and high Mo content compared to pyrite from methane seeps. These patterns suggest either more intense or persistent sulphidic conditions, or an intensified manganese (oxy)hydroxide shuttle process at oil seeps. Copper and Zn are enriched in oil seepagederived pyrite while Ni and V enrichment is less pronounced, suggesting either a selective uptake of specific elements by pyrite, or varying trace element compositions of organic compounds oxidised via microbial reduction.

show abstract