HR: 0830h
AN: OS51C-0870    [PDF]
TI: Stratigraphic and Structural Evolution of South Hydrate Ridge
AU: * Chevallier, J
EM: jchevall@coas.oregonstate.edu
AF: COAS, Oregon State Un., Ocean Admin Bld 104, Corvallis, OR 97331 United States
AU: Trehu, A M
EM: trehu@coas.oregonstate.edu
AF: COAS, Oregon State Un., Ocean Admin Bld 104, Corvallis, OR 97331 United States
AU: Meyer, J
EM: h2m@nwnatural.com
AF: Nortwest Natural, 220 NW 2nd Ave., Portland, )R 97209 United States
AU: Johnson, J E
EM: jjohnson@coas.oregonstate.edu
AF: COAS, Oregon State Un., Ocean Admin Bld 104, Corvallis, OR 97331 United States
AU: Bangs, N L
EM: nathan@utig.ig.utexas.edu
AF: UTIG, Un. of Texas at Austin, 4421 Spicewood Springs Rd., Austin, TX 78759 United States
AB: Hydrate Ridge is a structural high in the Cascadia accretionary wedge. A widespread seismic BSR suggests widespread occurrence of gas hydrate, but limited evidence for seafloor venting indicates inhomogeneous distribution of gas hydrate. We present a reconstruction of the geologic history of the southern part of Hydrate Ridge based on a high-resolution 3D seismic survey constrained by lithologic data from ODP Leg 204. The objective of this study is to better understand stratigraphic and structural features that affect the distribution of fluids in the subsurface and the migration pathways to cycle these fluids through the gas hydrate stability zone by mapping the strata and structures and reconstructing their former configuration. We conclude that southern Hydrate Ridge is composed of a landward-verging thrust fold, initiated ~1.2 mybp near the deformation front, which is juxtaposed against a dome-shaped core of older, fractured accretionary material. Several distinct and overlapping tectonic basins have formed as a result of interactions between these structures. These have been uplifted, folded, faulted and eroded in response to episodic uplift of the dome, resulting in the complicated structure imaged by the 3D seismic survey.
DE: 3025 Marine seismics (0935)
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting