@article{gledocs_11858_6877,
author = {Drake, Henrik and Åström, Mats E and Heim, Christine and Broman, Curt and Åström, Jan and Whitehouse, Martin and Ivarsson, Magnus and Siljeström, Sandra and Sjövall, Peter},
title = {Extreme (13)C depletion of carbonates formed during oxidation of biogenic methane in fractured granite.},
year = {2015},
volume = {6},

abstract = {Precipitation of exceptionally 13C-depleted authigenic carbonate is a result of, and thus a tracer for, sulphate-dependent anaerobic methane oxidation, particularly in marine sediments. Although these carbonates typically are less depleted in 13C than in the source methane, because of incorporation of C also from other sources, they are far more depleted in 13C (δ13C as light as -69‰ V-PDB) than in carbonates formed where no methane is involved. Here we show that oxidation of biogenic methane in carbon-poor deep groundwater in fractured granitoid rocks has resulted in fracture-wall precipitation of the most extremely 13C-depleted carbonates ever reported, δ13C down to -125‰ V-PDB. A microbial consortium of sulphate reducers and methane oxidizers has been involved, as revealed by biomarker signatures in the carbonates and S-isotope compositions of co-genetic sulphide. Methane formed at shallow depths has been oxidized at several hundred metres depth at the transition to a deep-seated sulphate-rich saline water. This process is so far an unrecognized terrestrial sink of methane.},
note = { \url {http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/6877}},
}