Physical Sciences and Mathematics Commons^™

Paleomagnetism Of The Late Cretaceous Ventura Member Of The Midnight Peak Formation, Methow-Pasayten Belt, North-Central Washington, David R. (David Richard) Bazard

WWU Graduate School Collection

Paleomagnetic analysis was conducted on 31 sites of the Ventura redbed Member of the Midnight Peak Formation located in the Methow-Pasayten belt, north-central Washington. Single high-stability components of magnetization, chiefly retained by high-unblocking temperature hematite exist in specimens from all but two of the sites. Directions calculated from these components were found to form circular within-site distributions and to be consistent across several meters of section. The single high-stability components, positive inclinations, and pre-folding, thus pre-Paleocene magnetizations suggest that the Ventura Member records a single Late Cretaceous dipole-field.

Proportionally untilting site-mean directions did not produce a reasonable field direction nor …

The Petrography And Tectonic Significance Of The Blue Mountain Unit, Olympic Peninsula, Washington, Jon M. Einarsen

WWU Graduate School Collection

The sedimentary rocks of the early to middle Eocene Blue Mountain unit compose the stratigraphic base of the otherwise predominantly basaltic Crescent Formation in the Olympic Peninsula, Washington. In the study area, primarily in northeastern portions of the Olympic Peninsula, the Blue Mountain unit consists of two distinct petrofacies, one a plagioclase-rich feldspathic arenite, the other a chert-rich lithic arenite. A third petrofacies is a feldspathic-lithic arenite and is a petrologic combination of the two distinct petrofacies. The source areas for the plagioclase-rich and chert-rich petrofacies are interpreted to be the Coast Plutonic Complex and San Juan Islands, respectively. The …