Sponsor
Portland State University. Department of Geology
First Advisor
Paul E. Hammond
Date of Publication
1987
Document Type
Thesis
Degree Name
Master of Science (M.S.) in Geology
Department
Geology
Language
English
Subjects
Stratigraphic geology -- Oligocene, Geology -- Washington (State) -- Ohanapecosh Formation, Volcanism -- Washington (State) -- Ohanapecosh Formation, Sedimentation and deposition -- Washington (State) -- Ohanapecosh Formation
DOI
10.15760/etd.5638
Physical Description
1 online resource (94 p.)
Abstract
Over 1055 m of early Oligocene andesitic-dacitic volcaniclastic rocks and minor interbedded andesitic lava flows of the Ohanapecosh Formation are exposed in a dissected structural high in the southern Washington Cascade Range, about 22 km southwest of Packwood, Washington.
The exposed sequence of rocks in the study area are located approximately 250 m above the base of the Ohanapecosh Formation. A lower sequence of deposits, about 350 m in thickness, are dominated by primary and reworked lithic lapilli-tuff and epiclastic channelized volcanic sandstone and conglomerate. These sediments are interpreted as pyroclastic flows and stream deposits, respectively. The upper sequence, about 455 m thick is dominated by volcanic diamictites interpreted as lahars, with minor lithic lapilli-tuff and epiclastic volcanic sandstone.
Rights
In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
Persistent Identifier
http://archives.pdx.edu/ds/psu/21174
Recommended Citation
Stine, Cynthia Marie, "Stratigraphy of the Ohanapecosh Formation north of Hamilton Buttes, southcentral Washington" (1987). Dissertations and Theses. Paper 3762.
https://doi.org/10.15760/etd.5638
Comments
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