Portland State University PDXScholar Dissertations and Theses Dissertations and Theses 1987 Explosion structures in Grande Ronde basalt of the Columbia Riverbasalt group, near Troy, Oregon Leonard Lee Orzol Portland State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/open_access_etds Part of the Geology Commons, and the Volcanology Commons Let us know how access to this document benefits ou.y Recommended Citation Orzol, Leonard Lee, "Explosion structures in Grande Ronde basalt of the Columbia Riverbasalt group, near Troy, Oregon" (1987). Dissertations and Theses. Paper 3750. https://doi.org/10.15760/etd.5634 This Thesis is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible:
[email protected]. AN ABSTRAST OF THE THESIS OF Leonard Lee Orzol for the Master of Science in Geology presented June 12, 1987. Title: Explosion Structures in Grande Ronde Basalt of the Columbia River Basalt Group, near Troy, Oregon. APPROVED BY MEMBERS OF THE THESIS COMMITEE: vin H. Beeson Explosion structures occur in flows of Grande Ronde Basalt in the study area near Troy, Oregon. Data from nineteen stratigraphic sites indicate that the maximum number of flows that contain explosion structures at any one site is six. In the informally named Troy flow, explosion structures are widespread. Each flow that contains explosion structures can be divided into two cooling units. The first cooling units occupy troughs in the pre-eruption topography and are up to 10 meters thick.