Physical Sciences and Mathematics Commons^™

Volcanology And Geochemistry Of The South Flank Of Mount Baker, Cascade Range, Washington, Douglas Mckeever

WWU Graduate School Collection

Major element chemical analysis of 97 rocks from the south side of Mount Baker was performed by energy dispersive x-ray fluorescence. Conclusions based on chemistry are:

1) Variation diagrams based on a large number of samples show that variation is not continuous nor, in general, smooth. Rocks from two major stratigraphic positions exhibit compositional coherency within each group and are interpreted as eruptive groups which were extruded over time intervals which were short compared to the lifetime of the volcanic center. The older of the two groups is called the Park Butte phase, and the younger is the Koma Kulshan …

Geology And Mineral Deposits Of The Southwest Quarter Of The Tanacross D-1 Quadrangle, Alaska, Roger Douglas Gill

WWU Graduate School Collection

The study area is in the northeast corner of the Tanacross quadrangle, east-central Alaska. Known as the Interior Porphyry belt, it lies between the Tintina fault to the north and the Denali fault to the south. Seven major porphyry copper-type deposits have been found within the belt since I969. Because much of the belt was unglaciated during Pleistocene time, the probability of finding a zone of supergene enrichment is enhanced. In Alaska a porphyry copper-type deposit with a supergene zone may improve the current economic status by helping to facilitate amortization of production capital costs.

The rocks within the study …

Petrology Of The Crystalline Rocks Of Vedder Mountain, British Columbia, Mitchell L. Bernardi

WWU Graduate School Collection

Vedder Mountain lies in Washington state and British Columbia on the western flank of the North Cascades. Metamorphic rocks, which comprise most of the western half of the mountain, can be divided into two separate and distinct units. The southern unit is composed of foliated and non-foliated hornblende-plagioclase gabbro with minor serpentinite and pyroxenite. Most of the gabbroic rocks are sheared and altered and exhibit a lower greenschist facies metamorphism overprinted by a subsequent prehnite-pumpellyite facies metamorphism. Whole-rock chemical analyses of the gabbros plot in and near the fields defined by oceanic gabbro (Engel and Fisher, 1969; Miyashiro et al, …

Petrology And Major Element Geochemistry Of Albite Granite Near Sparta, Oregon, Robert Brayton Almy Iii

WWU Graduate School Collection

Albite granite near Sparta, Oregon occurs in an igneous complex containing serpentinite, gabbro, diorite, tonalite and granite with overlying keratophyric and spilitic volcanic rocks. This igneous suite is overlain by Triassic limestones of reef origin. In all the igneous rocks primary hypidiomorphic and porphyritic textures predominate but a metamorphic overprint of the prehnite-pumpellyite facies is widespread. Whole rock chemical analyses show that albite granite has relatively high Si0₂ (69-81%) and Na₂0 (4-7%) and low K₂O (0.1-1%). Rare plagioclase potassium-feldspar granite contains up to 3.6% K₂O.

Although local isochemical alteration is demonstrable and local …