Publication Abstracts

Kennedy et al. 2001

Kennedy, M.J., N. Christie-Blick, and L.E. Sohl, 2001: Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth's coldest intervals? Geology, 29, 443-446, doi:10.1130/0091-7613(2001)029<0443:APCCAI>2.0.CO;2.

Regionally persistent, thin intervals of carbonate rock directly and ubiquitously overlie Proterozoic glacial deposits on almost every continent, and are commonly referred to as cap carbonates. Their unusual facies, stratigraphically abrupt basal and upper contacts, and strongly negative carbon isotopic signature (δ13C values between ∼0‰ and -5‰) suggest a chemical oceanographic origin, the details of which remain unresolved. Here we propose that these enigmatic deposits are related to the destabilization of gas hydrate in terrestrial permafrost following rapid postglacial warming and flooding of widely exposed continental shelves and interior basins. Supporting evidence for this hypothesis includes (1) the common occurrence within the cap carbonates of unusual fabrics, similar to those produced by cold methane seeps; (2) a distinctive time evolution for the carbon isotopic excursions indicative of a pulse addition of isotopically depleted carbon to the ocean- atmosphere system; and (3) agreement between mass-balance estimates of carbon released by hydrate destabilization and carbon buried in the cap carbonate. We infer that during times of low-latitude glaciation, characteristic of the Neoproterozoic, gas hydrates may have been in greater abundance than at any other time in Earth history.

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BibTeX Citation

@article{ke07000g,
  author={Kennedy, M. J. and Christie-Blick, N. and Sohl, L. E.},
  title={Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth's coldest intervals?},
  year={2001},
  journal={Geology},
  volume={29},
  pages={443--446},
  doi={10.1130/0091-7613(2001)029%3C0443%3AAPCCAI%3E2.0.CO;2},
}

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RIS Citation

TY  - JOUR
ID  - ke07000g
AU  - Kennedy, M. J.
AU  - Christie-Blick, N.
AU  - Sohl, L. E.
PY  - 2001
TI  - Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth's coldest intervals?
JA  - Geology
VL  - 29
SP  - 443
EP  - 446
DO  - 10.1130/0091-7613(2001)029%3C0443%3AAPCCAI%3E2.0.CO;2
ER  -

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