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GEOREF RECORD

Paleogene calderas of central and eastern Oregon; eruptive sources of widespread tuffs in the John Day and Clarno Formations

Jason D. McClaughry, Mark L. Ferns, Martin J. Streck, Karyn A. Patridge and Caroline L. Gordon
Paleogene calderas of central and eastern Oregon; eruptive sources of widespread tuffs in the John Day and Clarno Formations (in Volcanoes to vineyards; geologic field trips through the dynamic landscape of the Pacific Northwest, Jim E. O'Connor (editor), Rebecca J. Dorsey (editor) and Ian P. Madin (editor))
Field Guide (Geological Society of America) (December 2009) 15: 407-434

Abstract

The John Day Formation of central and eastern Oregon, contains a widespread assemblage of both ash-flow and airfall tuffs, yet only a few corresponding caldera sources have been identified in the region. Investigators have long speculated on the sources of tuffs in the John Day Formation and have suggested that these pyroclastic rocks were vented from now buried eruptive centers in or marginal to a nascent Cascade Range. Recent detailed geologic mapping in the John Day and Clarno Formations, however, indicates the presence of at least three large-scale rhyolite caldera complexes centered along the northeast-trending axis of the Blue Mountains. This field guide describes a three-day geologic transect, from the scenic high desert of central Oregon eastward across the axis of the Blue Mountains, that will examine the caldera exposed along the crest of the Ochoco Mountains, the 29.56 Ma Crooked River caldera at Princeville, and the 29.8 to 28.1 Ma Tower Mountain caldera near Ukiah.


ISSN: 2333-0937
EISSN: 2333-0945
Serial Title: Field Guide (Geological Society of America)
Serial Volume: 15
Title: Paleogene calderas of central and eastern Oregon; eruptive sources of widespread tuffs in the John Day and Clarno Formations
Title: Volcanoes to vineyards; geologic field trips through the dynamic landscape of the Pacific Northwest
Author(s): McClaughry, Jason D.Ferns, Mark L.Streck, Martin J.Patridge, Karyn A.Gordon, Caroline L.
Author(s): O'Connor, Jim E.editor
Author(s): Dorsey, Rebecca J.editor
Author(s): Madin, Ian P.editor
Affiliation: Oregon Department of Geology and Mineral Industries, Baker City, OR, United States
Affiliation: U. S. Geological Survey, Portland, OR, United States
Pages: 407-434
Published: 200912
Text Language: English
Publisher: Geological Society of America, Boulder, CO, United States
References: 76
Accession Number: 2010-060170
Categories: Geochemistry of rocks, soils, and sedimentsIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables, geol. sketch maps
N44°00'00" - N45°49'60", W121°30'00" - W118°30'00"
Secondary Affiliation: University of Oregon, USA, United StatesOregon Department of Geology and Mineral Industries, USA, United StatesPortland State University, USA, United StatesWashington State University, USA, United StatesOchoco National Forest, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201033
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