Carbonate cements indicate channeled fluid flow along a zone of vertical faults at the deformation front of the Cascadia accretionary wedge (northwest U.S. coast)

James C Sample, Mary Reid, H. J. Tobin, J. C. Moore

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

To understand the relation between fluid seeps and structures, sedimentary rocks were collected with the DSRV Alvin from a vertical fault zone that transects the deformation front of the Cascadia accretionary wedge. The rocks contained diagenetic carbonate cement that was precipitated from fluids expelled during accretion. Carbon, oxygen, and strontium isotope data are consistent with a fluid source at >2 km depth. Most carbon isotopes range from -1‰ to -25‰ (PDB standard) consistent with a thermogenic methane source. Oxygen isotopes show extreme 18O depletions that are consistent with precipitation from fluids with temperatures as high as 100°C. 87Sr/86Sr values of 0.709 75 to 0.712 79 may be due to strontium in fluids derived from clay-rich parts of the stratigraphic section. The ubiquity of carbonate precipitates and the isotope data indicate that the vertical fault zone is an efficient conduit for fluid dewatering from deep levels of the accretionary wedge. -Authors

Original languageEnglish (US)
Pages (from-to)507-510
Number of pages4
JournalGeology
Volume21
Issue number6
DOIs
StatePublished - 1993
Externally publishedYes

Fingerprint

accretionary prism
fluid flow
cement
carbonate
fluid
coast
carbon isotope
oxygen isotope
fault zone
strontium isotope
strontium
dewatering
sedimentary rock
transect
methane
accretion
isotope
clay
rock
temperature

ASJC Scopus subject areas

  • Geology

Cite this

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title = "Carbonate cements indicate channeled fluid flow along a zone of vertical faults at the deformation front of the Cascadia accretionary wedge (northwest U.S. coast)",
abstract = "To understand the relation between fluid seeps and structures, sedimentary rocks were collected with the DSRV Alvin from a vertical fault zone that transects the deformation front of the Cascadia accretionary wedge. The rocks contained diagenetic carbonate cement that was precipitated from fluids expelled during accretion. Carbon, oxygen, and strontium isotope data are consistent with a fluid source at >2 km depth. Most carbon isotopes range from -1‰ to -25‰ (PDB standard) consistent with a thermogenic methane source. Oxygen isotopes show extreme 18O depletions that are consistent with precipitation from fluids with temperatures as high as 100°C. 87Sr/86Sr values of 0.709 75 to 0.712 79 may be due to strontium in fluids derived from clay-rich parts of the stratigraphic section. The ubiquity of carbonate precipitates and the isotope data indicate that the vertical fault zone is an efficient conduit for fluid dewatering from deep levels of the accretionary wedge. -Authors",
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AU - Sample, James C

AU - Reid, Mary

AU - Tobin, H. J.

AU - Moore, J. C.

PY - 1993

Y1 - 1993

N2 - To understand the relation between fluid seeps and structures, sedimentary rocks were collected with the DSRV Alvin from a vertical fault zone that transects the deformation front of the Cascadia accretionary wedge. The rocks contained diagenetic carbonate cement that was precipitated from fluids expelled during accretion. Carbon, oxygen, and strontium isotope data are consistent with a fluid source at >2 km depth. Most carbon isotopes range from -1‰ to -25‰ (PDB standard) consistent with a thermogenic methane source. Oxygen isotopes show extreme 18O depletions that are consistent with precipitation from fluids with temperatures as high as 100°C. 87Sr/86Sr values of 0.709 75 to 0.712 79 may be due to strontium in fluids derived from clay-rich parts of the stratigraphic section. The ubiquity of carbonate precipitates and the isotope data indicate that the vertical fault zone is an efficient conduit for fluid dewatering from deep levels of the accretionary wedge. -Authors

AB - To understand the relation between fluid seeps and structures, sedimentary rocks were collected with the DSRV Alvin from a vertical fault zone that transects the deformation front of the Cascadia accretionary wedge. The rocks contained diagenetic carbonate cement that was precipitated from fluids expelled during accretion. Carbon, oxygen, and strontium isotope data are consistent with a fluid source at >2 km depth. Most carbon isotopes range from -1‰ to -25‰ (PDB standard) consistent with a thermogenic methane source. Oxygen isotopes show extreme 18O depletions that are consistent with precipitation from fluids with temperatures as high as 100°C. 87Sr/86Sr values of 0.709 75 to 0.712 79 may be due to strontium in fluids derived from clay-rich parts of the stratigraphic section. The ubiquity of carbonate precipitates and the isotope data indicate that the vertical fault zone is an efficient conduit for fluid dewatering from deep levels of the accretionary wedge. -Authors

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