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Pomona Member of the Columbia River Basalt Group: an intracanyon flow in the Columbia River Gorge, Oregon.

Oregon Geology

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Abstract

The Pomona Member of the Saddle Mountains Basalt (Columbia River Basalt Group) occurs as an intracanyon flow greater than 75m (250ft) thick along the S side of the Columbia River Gorge between Mitchell Point and Shellrock Mountain, Oregon. Best exposures are at Mitchell Point, where this flow caps more than 70m (230ft) of cobble conglomerate that partially fills a canyon cut into flows of the underlying Frenchman Springs Member. These exposures provide a necessary link between outcrops of the Pomona Member in the Columbia Plateau and western Washington. Post-Frenchman Springs, pre-Pomona canyon cutting implies deformation in the ancestral Cascade Range between about 14.5 and 12Ma ago.-Author

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Pomona Member of the Columbia River Basalt Group: an intracanyon flow in the Columbia River Gorge, Oregon.
Series title:
Oregon Geology
Volume
42
Issue:
12
Year Published:
1980
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
195
Last page:
199
Number of Pages:
5