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Methane‐flux‐dependent lateral faunal changes in a Late Cretaceous chemosymbiotic assemblage from the Nakagawa area of Hokkaido, Japan
Author(s) -
JENKINS ROBERT G.,
KAIM ANDRZEJ,
HIKIDA YOSHINORI,
TANABE KAZUSHIGE
Publication year - 2007
Publication title -
geobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.859
H-Index - 72
eISSN - 1472-4669
pISSN - 1472-4677
DOI - 10.1111/j.1472-4669.2007.00106.x
Subject(s) - petroleum seep , methane , carbonate , geology , cretaceous , cold seep , anaerobic oxidation of methane , geochemistry , carbon fibers , clastic rock , δ13c , isotopes of carbon , paleontology , mineralogy , stable isotope ratio , sedimentary rock , total organic carbon , chemistry , environmental chemistry , materials science , physics , organic chemistry , quantum mechanics , composite number , composite material
A Late Cretaceous carbonate body (2 m in maximum diameter) surrounded by clastic rocks, recently discovered in the Nakagawa area (Hokkaido, Japan), is interpreted as a methane‐seep deposit, on the basis of negative carbon isotopic composition (as low as −43.5‰), variable sulphide sulphur isotopic composition, high carbonate content, and in situ fractures. It most likely formed owing to methane‐bearing pore‐water diffusion. We estimate that the concentration of methane decreased toward the margin of the carbonate body, and that only small carbonate concretions were precipitated at a certain distance from the methane‐seep centre. These spatial characteristics coincide well with the observed pattern of faunal distribution. The gastropod‐dominated association (indeterminate abyssochrysids and ataphrids and the acmaeid limpet Serradonta sp. are most common) co‐occurs with lucinid and thyasirid bivalves ( Thyasira sp., Myrtea sp., and Miltha sp.), and was found within and just above the methane‐derived carbonate body. Acharax and Nucinella (solemyoid bivalves) are more typical of the peripheral part of the methane‐influenced sediments. We suggest that this pattern of faunal distribution reflects the decreasing concentration of methane and apparently also hydrogen sulphide when moving from the centre of discharge toward the periphery of the methane seep.