About 225 lava flows and ash-flow tuffs of the Deschutes Formation (DF) were mapped at Green Ridge. The units fill east-trending paleovalleys which "sky-out" westward and dip east; the eastward dip of the units decreases
as they are traced eastward. The source of the units was west of Green Ridge...
Hard copy of presentation delivered May 20, 2003, at OSU Memorial Union as part of a faculty panel, "USA PATRIOT Act Forum: Effects on Oregon State University." Sponsored by Faculty for Peace and Justice, and the Program for Ethics, Science and the Environment.
Four formations of the Cretaceous Nanaimo Group crop out on Galiano Island and on Parker and Gossip Islands, nearby. These formations are: early Campanian Geoffrey Formation which encloses a tongue of the Northumberland Formation; early Campanian to late Maestrichtian Spray Formation; and Maestrichtian Gabriola Formation. The stratigraphic succession has a...
Two ash-flow tuff units of the late Miocene-early Pliocene Deschute Formation in central Oregon were studied in detail because of the widespread distribution, diverse compositions, and stratigraphic importance.
The Lower Bridge tuff is a double-flow simple
cooling unit that is poorly welded. The upper flow grades from rhyolite in the...
A sequence of volcanic, volcaniclastic, and epiclastic deposits from Oligocene to Recent age are exposed in the region from Lake
Simtustus to Madras in central Oregon. The epiclastic sediments of the Oligocene John Day Formation are unconformably overlain by two flows of the middle Miocene Columbia River Basalt Group. The...
The Peck Mountain area is located in west-central Idaho just 15 miles east of the Oregon-Idaho border. It is tectonically located within the "Columbia Arc" of the Nevadan oroaenic belt. The Seven Devils Volcanics, Permian to Traissic in age, are the oldest rocks in the area. They are composed of...
The Whitewater River area is located directly east of Mt. Jefferson in the Cascades of central Oregon. Approximately 90 mi2 (230 km2) were mapped (scale 1/24,000) and four new K-Ar ages and 151 major element analyses were obtained in a study of the stratigraphic
and magmatic transition from the Miocene...
The Mitchell inlier in north-central Oregon contains the largest exposure of Cretaceous marine sedimentary rocks in this region. Nearly 9,000 ft of Albian-Cenamanian rocks are exposed along the flanks of the Mitchell anticline. The Cretaceous section rests unconformably overlain by Tertiary volcanic rocks. The Cretaceous rocks have previously been divided...
Geologic mapping of the Longview-Kelso area and the measurement and description of a composite 650-meter thick stratigraphic section of the Cowlitz Formation (Tc) in Coal Creek using bio-, magneto-, litho-, and sequence stratigraphy reveals a complex interplay of Cowlitz micaceous, lithic arkosic shelf to tidal/estuarine to delta
plain facies associations,...