The geology and natural gas potential of the Clatskanie 7.5-minute quadrangle in Columbia County, Oregon was studied utilizing a combination of geologic mapping, measuring of stratigraphic sections, diatom and molluscan fossil identifications, with subsurface geophysical data and petrographic and geochemical analyses. The stratigraphy of the study area consists of two...
The continuation of geoarchaeological investigations at Tseriadun (35CU7) contributes to the understanding of the site's depositional history and the associated environments, thereby identifying the long term geomorphic change in the area and providing the environmental context for local human activity as it is reflected in the archaeological record. Meeting this...
When you drive through the Madras region on U.S. Highway 97, you see a gently rolling plain dotted with low hills and flat-topped buttes. Since the plain appears to extend westward uninterruptedly to the foothills of the Cascade Range, little would you imagine that between you and the mountains lurk...
This report summarizes results of geologic mapping in the South Umpqua Falls region of the Western Cascade Range in Douglas County, southwestern Oregon (plate 1). Rocks of the Western Cascades range in age from late Eocene to late Miocene and consist of deformed and partially altered flows, pyroclastic rocks, and...
Snow Peak is a voluminous shield volcano located ~50 km west of the axis of
the modern Cascade arc. A previously published K-Ar age estimate indicates that the
Snow Peak lavas are ~3 Ma. Subsequently, the preliminary research framework for
studying the Snow Peak lavas focused on constraining the petrogenesis...
The Willamette Silt is a surficial geologic unit composed of successive Missoula Flood Deposits that underlies 3100 km2 (1200 mil) of arable land in the Willamette Valley of Oregon. The Willamette Silt protects the underlying regionally important Willamette
Aquifer from agricultural contamination while acting as a semi-confining unit and a...
Locating archaeological sites that predate the arrival of modern sea level has been difficult along the Oregon coast. This is in part believed to be the result of geologic processes that have influenced the preservation, distribution, and visibility of sites within the Oregon coastal landscape. Because of these changes, researchers...