Earth Sciences Commons^™

The Stratigraphy And Geochemistry Of The Crescent Formation Basalts And The Bedrock Geology Of Associated Igneous Rocks Near Bremerton, Washington, Kenneth P. Clark

WWU Graduate School Collection

A stratigraphic section developed for the Bremerton rocks in the Kitsap Peninsula suggests formation by rifting in a marine environment. Basal gabbro, dated by 40Ar/39Ar at 49.8 Ma plus or minus 0.8 Ma, and associated mafic to felsic plutonics, appear to be the source of a mafic dike complex that composes 100% of the stratigraphic level above the plutonics. These dikes are the apparent feeders to overlying submarine and subaerial volcanics. The previously unrecognized submarine sequence consists of interbedded basaltic breccia, tuffs, basalt flows, and basaltic sandstone, siltstone, and conglomerate. Approximately 1 km of columnar basalt flows cap the sequence. …

The Mechanisms Of Landslide Initiation And Flood Generation In The Boulder Creek Basin, Whatcom County, Washington, Monica E. Gowan

WWU Graduate School Collection

Over the past fifty years, the frequency of landsliding and flooding in the Boulder Creek basin, Whatcom County, Washington, has increased. This trend is examined through analysis of the landslides and their mechanisms of initiation, the conditions for generation of runoff during eight debris-laden floods, and long-term precipitation and land-use patterns. Thirteen active landslides are identified along the main channel of Boulder Creek, located within the shear zone of a late Eocene high-angle fault. Landslides are classified as debris slides and slump-earthflows. Average landslide volume is 8,700 cubic meters. The largest slide observed is 36,700 cubic meters. Slope angles range …

Sedimentary Petrology, Depositional Environment And Paleogeographic Significance Of The Upper Eocene Hoko River Formation, Northern Olympic Peninsula, Washington, Jennifer H. (Jennifer Helen) De Chant

WWU Graduate School Collection

The upper Eocene Hoko River Formation is the oldest formation of the Twin River Group. Exposures dipping to the northeast and north run across the northern Olympic Peninsula. The Hoko River Formation is composed of siltstone, turbidites, channel conglomerates and debris flows. The sandstones are lithic-arenites and -graywackes and are composed of fine to very coarse, moderately well sorted to poorly sorted sand. The dominant cement is calcite with minor polycrystalline quartz and zeolite cements. The average composition of the sandstones is quartz (Q) = 29%+14, feldspar (F) = 15%+9, and lithics (L) = 55%+12. Comparison of these data to …

A Study Of Fluid Inclusions And Geochemical Mechanisms For Gold Deposition, Cannon Mine, Wenatchee, Washington, Michael P. (Michael Peter) Klisch

WWU Graduate School Collection

The Carmen Mine is located 1 km south of the city of Wenatchee, Washington. The mine is hosted by lower to middle Eocene fluvial arkoses of unknown correlation. An unaltered rhyodacite dome, dated at 43.2 ± 8 Ma, bordered by perlite, intrudes the sediments and is separated from the orebody by a zone of sheared and faulted sediments. The western border of the orebody is a brecciated and weakly altered and mineralized andesite of probable early Eocene age. The structural geology of the mine area is quite complex and related to the formation of the Chiwaukum graben during the middle …

Timing And Conditions Of Deformation And Metamorphism Of The Structural Packages East Of Harrison Lake, B.C., Jeffrey D. (Jeffrey Dale) Bennett

WWU Graduate School Collection

Metamorphosed oceanic and arc-related lithologies of the Slollicum, Cogburn and Settler packages crop out to the east of Harrison Lake, B.C., within the southern Coast Plutonic Complex and represent the northern extension of the Cascade orogenic belt. The Cretaceous Spuzzum plutons intruded the packages in late syn- to post-metamorphic time, and several early Tertiary stocks intruded all units after deformation.

The Slollicum package is dominated by graphitic to politic phyllite, and felsic to mafic arc volcanics intercalated with marble, conglomerate and quartzite. The sediments dominate western exposures, and eastern exposures are mainly volcanics. U-Pb analysis of zircon in a volcanic …

Petrology And Structure Of The Cascade River Schist, In The Sibley Creek Area, Northern Cascades, Washington, Joe D. Dragovich

WWU Graduate School Collection

The focus of this study is on the protolith types, metamorphism and structure of the Cascade River Schist in the Sibley Creek area of the North Cascades, Washington. The two general lithologic packages are an arc and ocean floor unit termed the Cascade River and Napeequa units, respectively, by Tabor and others (in press). The Cascade River unit has a recognizable stratigraphy which is inverted and repeated across strike from the southwestern to northeastern sides of the field area, apparently as a result of macroscopic synclinal folding. The Napeequa unit lies on top of the Cascade River unit, in the …