Document Type

Article

Publication Date

8-1993

Keywords

Hydrothermal systems, Marine geology and geophysics, Heat flow (benthic), Sediment transport

Abstract

For the better part of 2 decades, it has been known that dewatering of sediments accreted to or subducted beneath accretionary wedges is a fundamental aspect of the subduction-accretion process. Yet, evidence for fluid flow in modern accretionary wedges is largely secondary and based on the presence of geochemical and/or thermal anomalies [e.g., Vrolijk et al., 1991]; the analysis of seismic velocity as an indicator of porosity, which suggests a progressive loss of pore volume in a landward direction [e.g., Bray and Karig, 1985]; and the occurrence of secondary sediment microstructures characteristic of fluid movement [e.g., Maltman et al., 1992].

The only quantitative measurements of fluid expulsion at surface vents are based on submersible-deployed, seepage-meter data [e.g.,Carson et al., 1990], and these results—coupled with the surface area of the vents—indicate flow rates significantly greater than can be supported by steadystate dewatering [Le Pichon et al., 1992]. The fluid budgets and mass fluxes associated with accretion are poorly constrained. Results of previous drilling suggest two distinct modes of fluid flow: channelized flow along fault zones (primarily the décollement [e.g., Mascle and Moore, 1990]) or diffuse flow, which is apparently accommodated by a pervasive fracture permeability [e.g.,Taira et al., 1992].

Publication Title

Eos, Transactions, American Geophysical Union

Volume

74

Issue

31

First Page

345

Last Page

347

Required Publisher's Statement

©1993. American Geophysical Union. All Rights Reserved.

DOI: 10.1029/93EO00459

Comments

AGU allows authors to deposit their journal articles if the version is the final published citable version of record, the AGU copyright statement is clearly visible on the posting, and the posting is made 6 months after official publication by the AGU.

Subjects - Topical (LCSH)

Hydrogeology--Washington (State); Sediments (Geology)--Washington (State)

Subjects - Names (LCNAF)

Ocean Drilling Program

Geographic Coverage

Cascadia Subduction Zone

Genre/Form

articles

Type

Text

Language

English

Format

application/pdf

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