TY - JOUR
T1 - Evidence of mass failure in the Hess Deep Rift from multi-resolutional bathymetry data
AU - Ferrini, Vicki Lynn
AU - Shillington, Donna J.
AU - Gillis, Kathryn
AU - MacLeod, Christopher J.
AU - Teagle, Damon A.H.
AU - Morris, Antony
AU - Cazenave, Pierre W.
AU - Hurst, Stephen
AU - Tominaga, Masako
N1 - Funding Information:
We gratefully acknowledge the captain and crew of the RRS James Cook , and the ROV Isis team, who made the acquisition of these data possible. Data acquisition and shipboard analysis were funded by the UK Natural Environment Research Council grant NE/C509023/1 to CJM and DAHT as part of the UKIODP Site Survey Initiative, additional data analysis was supported by the US Scientific Support Program (USSSP) grant PDA0808 to DJS and VLF. Comments by Doug Masson, Bill Ryan, and Leslie Hsu, Ryan Portner and an anonymous reviewer greatly improved the manuscript.
PY - 2013/5/1
Y1 - 2013/5/1
N2 - New regional swath and near-bottom bathymetric data provide constraints on shallow structures at the Hess Deep Rift, an oceanic rift that exposes the crust and upper mantle of fast-spreading oceanic lithosphere created at the East Pacific Rise. These data reveal the presence of a lobate structure with a length of ~. 4. km and a width of ~. 6. km south of an Intrarift Ridge, north of Hess Deep. The lobe consists of a series of concentric benches that are widest in the center of the lobe and narrower at the edges, with a dominant bench separating two distinct morphologic regions in the lobe. There are two end-member possible interpretations of this feature: 1) the lobate structure represents a mass failure with little translation that contains coherent blocks that preserve rift-related lineaments; or 2) it represents degraded tectonic structures, and the lobate form is accounted for by, for example, two intersecting faults. We favor the slump interpretation because it more readily accounts for the lobate form of the feature and the curved benches and based on the presence of other similar lobes in this region. In the slump model, secondary structures within the benches may indicate radial spreading during or after failure. The large lobate structure we identify south of the Intrarift Ridge in Hess Deep is one of the first features of its kind identified in an oceanic rift, and illustrates that mass failure may be a significant process in these settings, consistent with the recognition of their importance in mid-ocean ridges, oceanic islands, and continental rifts. Understanding the structure of the Hess Deep Rift is also important for reconstructing the section of fast-spreading oceanic crust exposed here.
AB - New regional swath and near-bottom bathymetric data provide constraints on shallow structures at the Hess Deep Rift, an oceanic rift that exposes the crust and upper mantle of fast-spreading oceanic lithosphere created at the East Pacific Rise. These data reveal the presence of a lobate structure with a length of ~. 4. km and a width of ~. 6. km south of an Intrarift Ridge, north of Hess Deep. The lobe consists of a series of concentric benches that are widest in the center of the lobe and narrower at the edges, with a dominant bench separating two distinct morphologic regions in the lobe. There are two end-member possible interpretations of this feature: 1) the lobate structure represents a mass failure with little translation that contains coherent blocks that preserve rift-related lineaments; or 2) it represents degraded tectonic structures, and the lobate form is accounted for by, for example, two intersecting faults. We favor the slump interpretation because it more readily accounts for the lobate form of the feature and the curved benches and based on the presence of other similar lobes in this region. In the slump model, secondary structures within the benches may indicate radial spreading during or after failure. The large lobate structure we identify south of the Intrarift Ridge in Hess Deep is one of the first features of its kind identified in an oceanic rift, and illustrates that mass failure may be a significant process in these settings, consistent with the recognition of their importance in mid-ocean ridges, oceanic islands, and continental rifts. Understanding the structure of the Hess Deep Rift is also important for reconstructing the section of fast-spreading oceanic crust exposed here.
KW - Bathymetry
KW - Hess Deep
KW - Mass failure
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U2 - 10.1016/j.margeo.2013.03.006
DO - 10.1016/j.margeo.2013.03.006
M3 - Article
AN - SCOPUS:84877882395
SN - 0025-3227
VL - 339
SP - 13
EP - 21
JO - Marine Geology
JF - Marine Geology
ER -