Physical properties and gas hydrate at a near‐seafloor thrust fault, hikurangi margin, New Zealand
File(s)FaultPaper_cleancopy.docx (2.26 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
The Pāpaku Fault Zone, drilled at International Ocean Discovery Program (IODP) Site U1518, is an active splay fault in the frontal accretionary wedge of the Hikurangi Margin. In logging‐while‐drilling data, the 33‐m‐thick fault zone exhibits mixed modes of deformation associated with a trend of downward decreasing density, P‐wave velocity, and resistivity. Methane hydrate is observed from ~30 to 585 m below seafloor (mbsf), including within and surrounding the fault zone. Hydrate accumulations are vertically discontinuous and occur throughout the entire logged section at low to moderate saturation in silty and sandy centimeter‐thick layers. We argue that the hydrate distribution implies that the methane is not sourced from fluid flow along the fault but instead by local diffusion. This, combined with geophysical observations and geochemical measurements from Site U1518, suggests that the fault is not a focused migration pathway for deeply sourced fluids and that the near‐seafloor Pāpaku Fault Zone has little to no active fluid flow.
Date Issued
2020-08-28
Date Acceptance
2020-07-29
Citation
Geophysical Research Letters, 2020, 47 (16), pp.1-11
ISSN
0094-8276
Publisher
American Geophysical Union (AGU)
Start Page
1
End Page
11
Journal / Book Title
Geophysical Research Letters
Volume
47
Issue
16
Copyright Statement
©2020. American Geophysical Union. All Rights Reserved. This is the accepted version of the following article: Cook, A. E., Paganoni, M., Clennell, M. B., McNamara, D. D., Nole, M., Wang, X., et al. (2020). Physical properties and gas hydrate at a near‐seafloor thrust fault, Hikurangi Margin, New Zealand. Geophysical Research Letters, 47, e2020GL088474, which has been published in final form at https://doi.org/10.1029/2020GL088474
Sponsor
Natural Environment Research Council [2006-2012]
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL088474
Grant Number
NE/S00291X/1
Subjects
Meteorology & Atmospheric Sciences
Publication Status
Published
Date Publish Online
2020-08-04