Geochemistry Commons^™

Geology And Geochemistry Of Hydrothermal Alteration, Eastern Portion Of The North Santiam Mining Area, J. Michael Pollock

Dissertations and Theses

The Ruth Mine is a base-metal vein deposit near the eastern margin of a reported porphyry copper deposit in the Western Cascade Range in Oregon. Uplift of the Western Cascade Range has resulted in a deeply dissected terrain in which more than a kilometer of the stratigraphy overlying the porphyry-style mineralization is preserved and exposed. The stratigraphic units, which are middle Tertiary in age, have been given arbitrary letter designations beginning with the lowest unit (Unit A) through the uppermost unit (Unit D).

Unit A is composed of fragmental rocks of andesitic composition. Overlying and interlayered with Unit A are …

A Geochemical Study Of The Rhododendron And Dalles Formations In The Area Of Mount Hood, Oregon, Marshall W. Gannett

Dissertations and Theses

The Miocene Rhododendron and Dalles Formations in the Mount Hood area are accumulations of chiefly pyroclastic andesitic material, largely confined to the Dalles-Mount Hood syncline. These very similar units are geographically separated by overlying andesites including the present Mount Hood cone, and past workers have suspected that they may share a common source. Prior to this study, few geochemical data were available for the Rhododendron and the Dalles Formations, compared to the well studied Columbia River basalts underlying them and the overlying Pliocene andesites. This geochemical study was designed to investigate certain aspects of the Rhododendron and Dalles Formations such …

Structure And Influence Of The Tillamook Uplift On The Stratigraphy Of The Mist Area, Oregon, Moinoddin Murtuzamiya Kadri

Dissertations and Theses

Fifty three sedimentary samples were analyzed for their minor and trace element concentrations utilizing instrumental neutron activation analysis. Concentrations of Na, K, La, Sm and Sc, and their ratios appear to establish significant trends. The data suggest a major break from a granitic-metamorphic provenance and a volcanic component dominated provenance between the Cowlitz and Keasey Formations respectively. The provenance of the Astoria Formation indicates the presence of flood basalts.

A Stratigraphic And Geochemical Investigation Of Ferruginous Bauxite Deposits In The Salem Hills, Marion County, Oregon, Charles William Hoffman

Dissertations and Theses

Pacific Northwest ferruginous bauxite deposits have formed in four main areas of northwestern Oregon and southwestern Washington by laterization of flows of the Columbia River Basalt Group (CRBG). The deposits, averaging 36.3% Al₂O₃ , 31.8% Fe₂O₃ , and 5.9% Sio₂, generally occur near the surface of hilltops in gently rolling areas. Two very different views have been advanced regarding the setting in which the deposits have formed. The first hypothesis calls for a blanket-type laterization by erosion of much of the original deposit upon uplift and dissection of the area.

Geophysical And Geochemical Analyses Of Selected Miocene Coastal Basalt Features, Clatsop County, Oregon, Virginia Josette Pfaff

Dissertations and Theses

The proximity of Miocene Columbia River basalts to the "locally-erupted" coastal Miocene basalts in northwestern Oregon, and the compelling similarities between the two groups, suggest that the coastal basalts, rather than being locally erupted, may be the westward extension of plateau basalts derived from eastern Oregon and Washington.

The local-origin hypothesis is based largely on the interpretation of coastal dikes and sills as representing vent areas; however, a complex mechanism, as yet unsatisfactorily defined, would be required to cause the eruption of virtually identical magmas simultaneously from source areas 500 km apart.

This study, therefore, has investigated the coastal basalt …

The Geology And Geochemistry Of The North Fork Stock, Northeastern Oregon, David Joseph Matty

Dissertations and Theses

The North Fork stock is a composite intrusive body of Late Jurassic-Early Cretaceous age which outcrops in the Blue Mountains of northeastern Oregon. The upper 600 m of the intrusion are exposed over an area of approximately 36 km² along the canyon walls of the North Fork of the John Day River in Grant and Umatilla counties. The stock intrudes metasediments, metavolcanics, and metagabbros associated with the Permian-Triassic Elkhorn Ridge Argillite. Contact metamorphism of the Elkhorn Ridge Argillite is developed to the hornblende-hornfels facies throughout most of the exposed area of this unit in the study area. The contact …

Catechol Effected Dissolution Of Silicate Minerals, James Maurice Kelley

Dissertations and Theses

The chemical properties of guanidinium tris(catecholato)siliconate, [(H₂N)₂C=NH₂]₂[Si(C₆H₄O₂)₃]·XH₂O (0 < X < 1), precipitated from an ammoniacal solution of silica and catechol by adding guanidinium hydrochloride, (H₂N)₂C=NH·HC1, were studied, and infrared, nmr, x-ray powder diffraction, and analytical data were gathered.

This same compound was, upon addition of' (H₂N)₂C=NH·HC1, isolated from 0.25, M aqueous catechol solutions buffered at pH 10 and containing the silicate minerals albite, andradite, muscovite, pyrophyllite, talc, and wollastonite, and also from unbuffered catechol solutions containing wollastonite and andradite.

It is concluded from this work that the formation of an anionic catechol-silicon complex, Si(C₆H₄O₂)₃²⁻, is largely responsible for the dissolution of the minerals mentioned above. From this conclusion, it is proposed that naturally occurring members of the class of organic compounds to which catechol belongs, the aromatic v̲i̲̲c̲-diols, may play …