About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 77 (1993)

Issue: 7. (July)

First Page: 1192

Last Page: 1207

Title: Methane in Columbia River Basalt Aquifers: Isotopic and Geohydrologic Evidence for a Deep Coal-Bed Gas Source in the Columbia Basin, Washington

Author(s): Vernon G. Johnson (2), David L. Graham (3), Stephen P. Reidel (4)


Methane occurs as a dissolved constituent in groundwater from confined aquifers in the Columbia River Basalt Group, Columbia basin, Washington. Isotopic compositions of methane in groundwater indicate that the methane is a mixture of biogenic (^dgr13C-CH4 to -88^pmil and ^dgr2H-CH4 to -265^pmil) and thermogenic (^dgr13C-CH4 to -35^pmil, and ^dgr2H-CH4 to -134^pmil) components. Chemical and isotopic data are consistent with entrainment of deep, coal-bed-generated methane in upwelling groundwater from below the Columbia River Basalt Group (>4 km) that mixes with near-surface groundwater. The areal distribution pattern of methane suggests that fault intersections are necessary for vert cal migration of deep methane through the basalt.

This study suggests that deep subbasalt coal-bed methane in the Columbia basin has infiltrated the shallow basalt groundwater system, and isotopic analyses of methane in groundwater from structurally favorable locations can be used to identify potential exploration targets. The wide areal distribution of methane in this large, relatively unexplored frontier province suggests economic gas reserves.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].