Silurian and Devonian rocks are exposed for approximately 8 square kilometers inthe KootenayArc structural province of northeastem Washington. These Middle Paleozoic rocks overlie the Upper Cambrian Metaline Limestone and the Ordovician Ledbetter Formation, which includes slates, siltstones, and limestones. Two Silurian units crop out in this area. Unit A is...
The Washougal Mining District is located on the western flanks of the southern Cascade Range of Washington, approximately 50 km (30 miles) northeast of Vancouver, Washington. The district has produced only $573 since 1903, derived from copper and silver. The presence of hydrothermal mineralization and breccia pipes similar to those...
The Washougal Mining District is approximately 50 km (30
miles) northeast of Vancouver, Washington, along the western
slopes of the Cascade Range. Although the district has produced
the unostentatious amount of $572 in metals since 1903, the presence
of porphyritic intrusions, hydrothermal alteration, breccia pipes,
and base-metal mineralization typical of...
An investigation was conducted to determine the origin of
Mima mounds in Jackson County, Oregon and Thurston County,
Washington. Data on soil morphology, mineralogy, and particle
size distribution were used to test the periglacial ice wedge hypothesis,
the gopher hypothesis, the erosional hypothesis, and the
loess hypothesis.
The results of...
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,...