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Title: Glacial cycles influence marine methane hydrate formation

Methane hydrates in fine-grained continental slope sediments often occupy isolated depth intervals surrounded by hydrate-free sediments. As they are not connected to deep gas sources, these hydrate deposits have been interpreted as sourced by in situ microbial methane. We investigate here the hypothesis that these isolated hydrate accumulations form preferentially in sediments deposited during Pleistocene glacial lowstands that contain relatively large amounts of labile particulate organic carbon, leading to enhanced microbial methanogenesis. To test this hypothesis, we apply an advection-diffusion-reaction model with a time-dependent organic carbon deposition controlled by glacioeustatic sea level variations. In the model, hydrate forms in sediments with greater organic carbon content deposited during the penultimate glacial cycle (~120-240 ka). As a result, the model predictions match hydrate-bearing intervals detected in three sites drilled on the northern Gulf of Mexico continental slope, supporting the hypothesis of hydrate formation driven by enhanced organic carbon burial during glacial lowstands.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [1]
  1. Columbia Univ., New York, NY (United States)
  2. The Ohio State Univ., Columbus, OH (United States)
  3. Univ. of Texas at Austin, Austin, TX (United States)
Publication Date:
Grant/Contract Number:
FE0013919; FE0023919
Type:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 45; Journal Issue: 2; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Research Org:
Univ. of Texas at Austin, Austin, TX (United States)
Sponsoring Org:
USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Methane hydrates; Pleistocene glacial cycles; Microbial methanogenesis
OSTI Identifier:
1417464
Alternate Identifier(s):
OSTI ID: 1418410

Malinverno, A., Cook, A. E., Daigle, H., and Oryan, B.. Glacial cycles influence marine methane hydrate formation. United States: N. p., Web. doi:10.1002/2017GL075848.
Malinverno, A., Cook, A. E., Daigle, H., & Oryan, B.. Glacial cycles influence marine methane hydrate formation. United States. doi:10.1002/2017GL075848.
Malinverno, A., Cook, A. E., Daigle, H., and Oryan, B.. 2018. "Glacial cycles influence marine methane hydrate formation". United States. doi:10.1002/2017GL075848.
@article{osti_1417464,
title = {Glacial cycles influence marine methane hydrate formation},
author = {Malinverno, A. and Cook, A. E. and Daigle, H. and Oryan, B.},
abstractNote = {Methane hydrates in fine-grained continental slope sediments often occupy isolated depth intervals surrounded by hydrate-free sediments. As they are not connected to deep gas sources, these hydrate deposits have been interpreted as sourced by in situ microbial methane. We investigate here the hypothesis that these isolated hydrate accumulations form preferentially in sediments deposited during Pleistocene glacial lowstands that contain relatively large amounts of labile particulate organic carbon, leading to enhanced microbial methanogenesis. To test this hypothesis, we apply an advection-diffusion-reaction model with a time-dependent organic carbon deposition controlled by glacioeustatic sea level variations. In the model, hydrate forms in sediments with greater organic carbon content deposited during the penultimate glacial cycle (~120-240 ka). As a result, the model predictions match hydrate-bearing intervals detected in three sites drilled on the northern Gulf of Mexico continental slope, supporting the hypothesis of hydrate formation driven by enhanced organic carbon burial during glacial lowstands.},
doi = {10.1002/2017GL075848},
journal = {Geophysical Research Letters},
number = 2,
volume = 45,
place = {United States},
year = {2018},
month = {1}
}

Works referenced in this record:

Carbon and hydrogen isotope systematics of bacterial formation and oxidation of methane
journal, September 1999