Geology Commons^™

The Mineralogy, Petrology And Geochemistry Of The Uranium-Bearing Vein Deposits Near Boulder, Montana, And Their Relationship To Faulting And Hot Spring Activity, Stanton Parker Dodd

WWU Graduate School Collection

Three "siliceous reef" uraniferous vein deposits of the Boulder batholith were studied. Two of these, the Free Enterprise and the W. Wilson, occur within hydrothermally altered Late Cretaceous Butte Quartz Monzonite and related rocks. Both deposits contain fine-grained iron and base-metal sulfides and uraninite in a matrix of microcrystalline quartz and chalcedony. The deposition of uraninite in these veins was contemporaneous with the majority of the sulfide minerals. The third deposit studied, the uraniferous Red Rock Mine, is similar in many respects to the other two occurrences, yet occurs within altered Late Cretaceous Elkhorn Mountains Volcanics.

All three occurrences formed …

The Chemical Composition Of The Shuksan Metamorphic Suite In The Gee Point - Finney Creek Area, North Cascades, Washington, Leah V. Street-Martin

WWU Graduate School Collection

Samples from the Shuksan Metamorphic Suite in the Gee Point-Finney Creek area were analyzed for twelve major elements and for the trace elements Y, Sr, Rb, Sc, Ni, Cr, Cu, Zr and Ba. The chemical compositions suggest that the protolith for the blueschist and greenschist was tholeiitic basalt, that the protolith for the iron-rich metasediment was a hydrothermally-formed sea floor precipitate on an active oceanic ridge and that the pelitic schists were once deep sea pelagic sediments. This assemblage probably formed along an oceanic spreading ridge.

Geology And Structure Of The Western And Southern Margins Of Twin Sisters Mountain, North Cascades, Washington, Frederic I. Frasse

WWU Graduate School Collection

Detailed mapping of the Goat Mountain dunite and the western and southern margins of the Twin Sisters dunite indicates that the structural setting of these bodies is dominated by high-angle northwest-trending fault zones. The Goat Mountain dunite overlies rocks of the Chilliwack Group and Yellow Aster Complex as a lowangle, west-dipping slab approximately 2500 feet thick. Cretaceous phyllite west of Goat Mountain overlies Chilliwack Group rocks along a similar low-angle west-dipping fault contact. These structures are both truncated by high-angle fault zones.

The timing of faulting is poorly constrained. High-angle faulting is at least post-Eocene through Holocene (?), and may …

Stratigraphy, Lithology, And Depositional Environment Of The Black Prince Formation Southeastern Arizona And Southwestern New Mexico, Patrick Kevin Spencer

WWU Graduate School Collection

The Black Prince Formation (new manuscript name) of southeastern Arizona and southwestern New Mexico is subdivided into four lithologic facies representing four environments of deposition. The first lithofacies consists of the basal member of the type section of the Black Prince Limestone and is a result of erosion and reworking of the underlying Escabrosa Limestone. The three limestone lithofacies suggest deposition on a shallow shelf under supratidal, intertidal and subtidal conditions. Cyclic fluctuations in sea level are seen in the rock record in the vertical alternation of lithofacies. Six unconformities are recognized and these are traceable throughout the region.

The …

Geology, Petrology, And Paleomagnetism Of Eocene Basalts From The Black Hills, Washington Coast Range, Brian R. Globerman

WWU Graduate School Collection

Geologic mapping in the Black Hills area strongly suggests that the middle Eocene basalts of the Crescent Formation and over- lying upper Eocene and Oligocene sedimentary rocks constitute a structurally coherent terrane that is bounded by northeast- and northwest-trending faults. I interpret the Black Hills as a homocline which dips about 10° to 15° to the west. Units within the block are commonly cut by normal and reverse faults, but are not appreciably folded.

Major- and trace-element geochemical analyses indicate that the Black Hills suite is co-magmatic, and is composed of hyper- sthene-normative tholeiites which were apparently derived by plagioclase …

Geology And Petrology Of The Lake Ann Stock And Associated Rocks, Eric William James

WWU Graduate School Collection

The Lake Ann stock is a two pyroxene quartz monzodiorite to granodiorite epizonal intrusive emplaced into the Shuksan thrust fault in the latest Pliocene. It is similar to other Late Tertiary Cascade intrusives in mineralogy, texture, chemistry, and setting. These similarities are attributable to near surface emplacement, quick cooling and magmatic arc setting. Epizonal emplacement is indicated by fine, equigranular textures, granophyre, late stage alteration, late miarolitic dikes, plagioclase resorbed by alkali feldspar, and low pressure contact metamorphic assemblages. Temperature of emplacement was between 600°C and 925°C; pressure was less than 2 kb. Chemistry of individual samples and variation diagrams …

The Shuksan Metamorphic Suite And Shuksan Thrust Mt Watson Area, North Cascades, Washington, Ralph Albert Haugerud

WWU Graduate School Collection

Rocks of the Shuksan Metamorphic Suite exposed on Mt Watson are metamorphosed pillow basalts, basaltic flows (?), basaltic tuffs, carbonaceous sediments, Mn-enriched cherty sediments, rare calcareous sediments and rare ferromanganese nodules.

Greenschist of the Suite records the following history: 1) early static hydrothermal metamorphism; 2) Early Cretaceous (about 125 ma ago) synkinematic blueschist-facies metamorphism at P~7 kb, T~350° C, ^Pfluid ^{near P}total, ^XCO₂ < 0.1, with production of S₁ and L₁ ; 3) late-metamorphic isoclinal folding (F₂) around axes commonly at high angles to L₁; 4) L₃ crenulation of S₁. Phyllite of the …

Tectonic Rotations In The Cascade Mountains Of Southern Washington, Roger G. (Roger Glenn) Bates

WWU Graduate School Collection

Paleomagnetic directions from 34 widely distributed sampling sites in the Oligocene Ohanapecosh Formation in the Cascade Mountains of southern Washington are well grouped with a mean and confidence interval of: Dec. = 27°, Inc. = 64°, α₉₅ = 4°. When compared to the expected direction, computed from the Oligocene reference pole for stable North America, a clockwise rotation of 31° ± 12° is apparently present. This result is not significantly different from other studies within the Cascades and Coast Range of southern Washington and suggests that the two Ranges have rotated as a single unit during late Eocene to …

The Petrology, Petrography, And Geochemistry Of The Black Jack Breccia Pipe, Silver Star Plutonic Complex, Skamania County, Washington, Robert H. Birk

WWU Graduate School Collection

Tourmaline-bearing breccia pipes are associated with late stage Tertiary porphyritic intrusive rocks in the Silver Star Plutonic Complex.

Whole-rock geochemical analysis of rocks from the complex show a silica vs. alumina/(K₂O + Na₂O + CaO) trend (Feiss, 1978) toward geochemical conditions favorable for porphyry copper-type mineralization. Copper present in diorite, quartz diorite, and quartz diorite porphyry rocks probably entered silicates, whereas copper formed porphyry copper-type mineralization in the more felsic granodiorite and granodiorite porphyry intrusions.

Optical, x-ray, and chemical analyses indicate two distinct populations of tourmaline present in the breccia pipes; an early "Hemlock Ridge-type" which …

Neoglaciation Of Avalanche Gorge And The Middle Fork Nooksack River Valley Mt. Baker, Washington, Steven Richard Fuller

WWU Graduate School Collection

The Neoglacial fluctuations of two of Mt. Baker's alpine glaciers were studied by tephrochronologic, dendrochronologic, and relative dating methods coupled with detailed geologic mapping. The earliest recognizable advance of the Deming Glacier occurred prior to deposition of Mazama tephra and after the Vashon Stade of Fraser Glaciation. The oldest recognizable Holocene advance of the Deming Glacier occurred >800 years B.P. and 16th, 17th, 18th(?), early 19th, late 19th, and 20th centuries. The Neoglacial record for the Rainbow Glacier is poorly preserved due to modification by two historic rock-debris avalanches, but the 20th century moraines of the Rainbow and Deming Glaciers …

Quaternary Geology And Stratigraphy Of Kitsap County, Washington, Jerald D. Deeter

WWU Graduate School Collection

New radiocarbon dates and stratigraphic evidence indicate correlations between stratigraphic units on Whidbey Island and in Kitsap County. Eight new C¹⁴ dates and five previous dates, together with the stratigraphic position of units and similarities in their composition, support the concept that the Double Bluff Drift, Whidbey Formation, and possibly Possession Drift, extend south of Whidbey Island into Kitsap County.

In Kitsap County, fine-grained floodplain deposits of the Whidbey Formation, with radiocarbon dates beyond the limits of conventional laboratory methods, are located at higher elevations than adjacent floodplain deposits of the Olympia nonglacial interval. This stratigraphic relationship suggest that …

A Paleocurrent Analysis Of A Portion Of The Chuckanut Depositional Basin Near Bellingham, Washington, James Norman Hartwell

WWU Graduate School Collection

The Chuckanut Formation is an upper Cretaceous to lower Tertiary sequence of conglomerate, sandstone, siltstone, and some coal deposited by streams near Bellingham, in western Whatcom County, Washington. Paleocurrent analysis of an area in the northwestern portion of the Chuckanut Formation shows two stream directions: to the south or southeast for the lower and middle sections and to the west or northwest for the upper section of the unit. Distinct differences in the lithology of clasts in the conglomerates support this conclusion. Angular phyllitic and quartz clasts in the lower and middle sections probably were derived locally from the Barrington …

Stratigraphy And Petrology Of The Nooksack Group In The Glacier Creek-Skyline Divide Area, North Cascades, Washington, Jon Niels Sondergaard

WWU Graduate School Collection

The 6-7 kilometer thick Upper Jurassic-Lower Cretaceous Nooksack Group is divided informally into four units on the basis of lithology. The basal unit consists of tuffaceous sandstone and keratophyric tuff with minor intercalations of argillite and intermediate crystalline volcanic rocks. The lower unit is composed of interbedded black argillite and volcaniclastic sandstone. The middle unit consists of thick-bedded volcaniclastic sandstone and coarse, sedimentary breccia with minor argillite. The upper unit is comprised of interbedded black argillite and volcaniclastic sandstone.

Lithologies and sedimentary structures within these units suggest: (1) the lower and upper units represent depositional lobe deposits of a middle …

Coastal Zone Processes And Geomorphology Of Skagit County, Washington, Ralph Francis Keuler

WWU Graduate School Collection

Geomorphic mapping of 130 km of marine shoreline in Skagit County reveals repeated morphologic and sedimentologic trends along many segments of the coast. The shoreline segments within which the trends are repeated are the littoral drift cells or shore drift sectors that act as nearly closed systems with respect to longshore sediment transport. The longshore trends include changes in mean grain size of beaches, sediment sorting, foreshore morphology, back- shore width and morphology, bluff morphology, and mean beach slope. The last parameter, slope, can be used as an index or surrogate measure of simultaneous changes in the other longshore trends. …

Clay Mineralogy And Origin Of The Huntingdon Fire Clays On Canadian Sumas Mountain, South British Columbia, Duane G. Horton

WWU Graduate School Collection

Three fire clay seams occur near the base of the Eocene Huntingdon formation at Canadian Sumas Mountain, southwest British Columbia. The three seams are separated from each other and overlain by coal partings.

The fire clays consist predominately of b-axis disordered kaolinite with minor amounts of quartz, detrital coal and x-ray amorphous iron oxides. They contain scant amounts of anatase, siderite, illite, and expandable clays. Expandable clays are concentrated in the fine clay fractions and illite is concentrated in the coarse clay fractions.

The lowermost fire clay seam contains better ordered kaolinite and fewer non-kaolinitic minerals than do the overlying …

Stratigraphy And Chronology Of Raised Marine Terraces, Bay View Ridge, Skagit County, Washington, Robert T. Siegfried

WWU Graduate School Collection

The evidence presented suggests that terraces and related features found on Bay View Ridge, Skagit County, Washington are raised marine in origin, and formed 13,000 - 11,000 years before present during the Everson Interstade of the Fraser Glaciation. Methods of investigation included topographic profiling, geologic mapping of surface deposits, identifying primary sedimentary structures, grain-size distribution analyses, identifying textural surface features on quartz grains utilizing the Scanning Electron Microscope and radiocarbon age dating.

Little or no measurable differential vertical tectonic and/or glacio-isostatic relative movement has occurred at Bay View Ridge since the Everson Interstade. Volcanic ash found in two peat bogs …

The Geology Of Southwestern Fidalgo Island, Daryl Gusey

WWU Graduate School Collection

Detailed geologic mapping of rocks in the upper stratigraphic levels of the Fidalgo ophiolite Indicates that keratophyres and spilites are interbedded with tuffaceous sediments, sedimentary breccias, and graywacke. Sedimentary breccias containing plutonlc rock fragments as well as volcanic rock fragments are common. The graywackes were derived from a volcanic source area. Radiolaria In the tuffaceous sediments indicate a depositional age of Lower Kimmeridgian to Upper Valanginian.

Compared to the stratigraphy and petrology of other ophiolites and present-day tectonic environments, the Fidalgo Complex most closely resembles that of ancient and modern island-arc sequences.

Paleomagnetism And Tectonic Significance Of The Goble Volcanics Of Southern Washington, Cynthia D. Burr

WWU Graduate School Collection

The upper Eocene to lower Oligocene Goble Volcanic series of southwest Washington is a thick sequence of areal to submarine basaltic to andesitic flows, pyroclastics, and minor sediments. Major element geochemical analyses suggest that these rocks may represent early magmatism of the Cascade arc. Paleomagnetic results from 37 sites indicate that the direction of remanent magnetization in the Goble Volcanics has a declination of 18.5°, an inclination of 57.5°, and a circle of 95% confidence (∝ ₉₅)of 4.33°. The expected upper Eocene direction in the sampling area is D = 353.5°; Ī = 61.5°. Thus the Goble Volcanics block …

Pennsylvanian And Early Permian Depositional Framework, Southeastern Arizona, Charles A. Ross

Geology Faculty Publications

This summary of the Pennsylvanian and Early Permian depositional framework in southeastern Arizona and adjacent regions is based in large part on the data and conclusions presented earlier in more detail by Ross (1973, 1978). The general stratigraphy of the Pedregosa, Orogrande and Permian basins and much of the literature has recently been summarized by Greenwood and others (1977).

In southeastern Arizona, Pennsylvanian and Permian strata are well exposed in many of the Basin and Range uplifts, where they may be studied in considerable detail. Mesozoic and Cenozoic structures, including local thrust faulting, and the attendant possibility of considerable lateral …

Coal Petrology Of The Tulameen Coalfield, South Central British Columbia, V. Eileen Williams

WWU Graduate School Collection

The Tulameen Coalfield lies in a small, southeast plunging syncline in the Intermontane Belt of the Canadian Cordillera in south central British Columbia. The coal is interbedded with fluvial and lacustrine sediments of the Eocene Allenby Formation of the Princeton Group. The abundance of tephra and bentonite indicates volcanic activity was contemporaneous with coal and sediment deposition.

Although coal occurs on both sides of the basin, its economic importance is currently restricted to a 15-21 meter thick coal seam on the southwestern limb of the syncline. The coal is predominantly vitrain and clarain composed of greater than 90 percent vitrinite. …

Shoreline Processes And Sediment Responses Related To The Origin Of Beach Cusps On Whidbey And Fidalgo Islands, Washington, John V. Spasari

WWU Graduate School Collection

Beach cusps are rhythmically spaced, crescentic beach features which consist of cusp shaped seaward pointing depositional ridges or mounds, often referred to as horns, separated by concave seaward troughs or bays. They have longshore spacings that vary from a few centimeters up to 25 meters. The purpose of the project was to conduct a field investigation of the shoreline processes and sediment responses associated with beach cusp formation on Whidbey and Fidalgo Islands, Washington. Despite the many theories published in the literature for the origin of beach cusps, many of which are contradictory, there were only two theories proposed that …

The Origin Of Serpentinites Associated With The Shuksan Metamorphic Suite Near Gee Point, Washington, Daniel L. Wilson

WWU Graduate School Collection

Metavolcanic and metasedimentary rocks of the Shuksan Metamorphic Suite near Gee Point have been contact metamorphosed by high-temperature emplacement of ultramafic rock. This intrusion occurred at great depth (>25 km) and caused contact temperatures of about 500°C, resulting in epidote-amphibolite facies metamorphism. Minerals of the contact metamorphism are overprinted by mineral assemblages of the regional Shuksan blueschist facies metamorphism. The K/Ar age of the epidote-amphibolites is Jurassic (145-160 m.y.), and thus the age of Shuksan metamorphism is probably younger than Middle Jurassic.

Ultramafic rocks found near Gee Point have been metamorphosed to serpentinites during Shuksan metamorphism and should be …

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 …

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 …

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, …

Paleomagnetism Of The San Juan Volcanic Field, Southwestern Colorado, Steven Douglas Sheriff

WWU Graduate School Collection

Geologic Setting

The San Juan volcanic field of southwestern Colorado consists of 2.5 X 10⁴ km² of volcanic rocks ranging in age from early Oligocene to Pliocene. Major volcanic activity in the San Juan field began about 35 million years ago with widespread eruption of rhyodacitic to andesitic lavas from scattered volcanic centers (Lipman and others, 1970). This type of volcanism peaked about 33 million years ago and then began to decline. About 30 million years ago, volcanic activity once again increased in the area. This time the eruptions were ash flows of intermediate to felsic composition. The …

Geology Of The Older Precambrian Rocks In The Vicinity Of Clear Creek And Zoroaster Canyon, Grand Canyon, Arizona, William S. Lingley Jr.

WWU Graduate School Collection

The Clear Creek-Zoroaster Canyon area is located in the east- central section of the Bright Angel Quadrangle (Maxson, 1968) roughly seven miles east northeast of Grand Canyon Village, Arizona. The boundaries of the present study area are shown in Figure 1. The study area extends from Mile 83.7 to Mile 86 on the Colorado River below Lee's Ferry, Arizona.

Older Precambrian rocks are exposed along the Inner Gorge of the Colorado River. They also crop out at Zoroaster Canyon, Clear Creek, and Cremation Creek. There are over 450 m of vertical exposure. Many outcrops are inaccessible due to steepness of …

Paleomagnetism Of Late Pleistocene Sediments, Puget Lowland, Washington, Kurt L. Othberg

WWU Graduate School Collection

Establishment of late Pleistocene geomagnetic polarity events would provide useful time indices for regional and interregional stratigraphic correlations. Development of a geomagnetic polarity scale tied to radiocarbon dating for the Puget Lowland helps to elucidate the possible occurrence of world-wide (dipole) reversed events during the last 50,000 years. Stability and reliability tests indicate that late Pleistocene sediments exposed in the Puget Lowland record valid paleomagnetic directions. Puget Lowland geomagnetic polarity for the interval 11,000 years to 30,000 years BP was normal except for a short reversed period between 20,000 years and 15,000 years BP. In addition to sampling errors and …

Petrogenesis Of The Granitic Rocks Of Part Of The Upper Granite Gorge, Grand Canyon, Arizona, Michael B. Walen

WWU Graduate School Collection

The study area extends from Phantom Creek to Crystal Creek, a distance of approximately 10 miles along the Colorado River. The units exposed are the Precambrian Vishnu Schist granitic to granodioritic units in Phantom Canyon, Trinity Canyon, and near Crystal Creek, and pegmatites and aplites. The Vishnu Schist is composed mostly of quartzo-feldspathic schists. The assemblage quartz-oligoclase-muscovite-biotite-sillimanite-K-feldspar indicates metamorphic conditions in the upper amphibolite facies between Phantom Creek and Mile 95. Between Mile 95 and Crystal Creek, assemblages indicate lower amphibolite to greenschist facies conditions.

The Phantom Granitic Complex consists of granodioritic and quartz monzonitic units. The presence of a …