Evolution of fluid expulsion and concentrated hydrate zones across the southern Hikurangi subduction margin, New Zealand: An analysis from depth migrated seismic data

Plaza-Faverola, Andreia, Klaeschen, Dirk, Barnes, Philip, Pecher, Ingo, Henrys, Stuart and Mountjoy, Joshu (2012) Evolution of fluid expulsion and concentrated hydrate zones across the southern Hikurangi subduction margin, New Zealand: An analysis from depth migrated seismic data Geochemistry Geophysics Geosystems, 13 . Q08018. DOI 10.1029/2012GC004228.

[img]
Preview
Text
2012GC004228.pdf - Published Version

Download (13Mb) | Preview

Supplementary data:

Abstract

Identification of methane sources controlling hydrate distribution and concentrations in continental margins remains a major challenge in gas hydrate research. Lack of deep fluid samples and high quality regional scale seismic reflection data may lead to underestimation of the significance of fluid escape from subducting and compacting sediments in the global inventory of methane reaching the hydrate zone, the water column and the atmosphere. The distribution of concentrated hydrate zones in relation to focused fluid flow across the southern Hikurangi subduction margin was investigated using high quality, long offset (10 km streamer), pre-stack depth migrated multichannel seismic data. Analysis of low P wave velocity zones, bright-reverse polarity reflections and dim-amplitude anomalies reveals pathways for gas escape and zones of gas accumulation. The study shows the structural and stratigraphic settings of three main areas of concentrated hydrates: (1) the Opouawe Bank, dominated by focused periodic fluid input along thrust faults sustaining dynamic hydrate concentrations and gas chimneys development; (2) the frontal anticline, with a basal set of protothrusts controlling permeability for fluids from deeply buried and subducted sediments sustaining hydrate concentrations at the crest of the anticline; and (3) the Hikurangi Channel, with buried sand dominated channels hosting significant amounts of gas beneath the base of the hydrate zone. In sand dominated channels gas injection into the hydrate zone favors highly concentrated hydrate accumulations. The evolution of fluid expulsion controlling hydrate formation offshore southern Hikurangi is described in stages during which different methane sources (in situ, buried and thermogenic) have been dominant.

Document Type: Article
Keywords: Hikurangi margin; concentrated hydrates; depth migrated seismic; methane sources; subduction; GAS-HYDRATE; ACCRETIONARY COMPLEX; STABILITY ZONE; BLAKE RIDGE; CONTINENTAL MARGINS; MARINE-SEDIMENTS; SAND RESERVOIRS; METHANE HYDRATE; OPOUAWE BANK; FLOW
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
DOI etc.: 10.1029/2012GC004228
ISSN: 1525-2027
Projects: Future Ocean
Date Deposited: 11 Oct 2012 07:48
Last Modified: 01 Mar 2018 12:43
URI: http://eprints.uni-kiel.de/id/eprint/16439

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...