District-scale zoning of ore deposits and structural-tectonic setting of Bau was investigated. Regional tectonic studies, structural analysis, and field mapping complemented by aeromagnetic interpretation were integrated to a structural model of Bau. Ores were studied with optical and electron microscopy, followed by major and trace element, fluid inclusion, and lead and sulfur isotope analyses. In the Late Triassic, Bau was in an island arc - back-arc basin environment Following Early Jurassic deformation and uplift, an active margin developed. Subduction of the West Pacific oceanic plate under the NW Kalimantan block began. Erosion of the Triassic Serian Volcanics produced extensive turbidite flows of the Pedawan Formation since the Latest Jurassic. Coeval development of rudist patch reefs on an unstable shelf edge of the overriding plate lasted until Cenomanian. Accretion of the turbidites ended in the Latest Cretaceous. Early Tertiary molasse deposition ended with a Mid-Eocene event. A 200-km-Iong, crustal-scale complex fault system involving dextral strike-slip and wrench faulting, termed the Bau Trend, developed during Mid-Miocene post-subduction regional extension. The principal mineralization event at Bau took place at 12-10 m.a., when I-type, calc-alkaline, reduced granodiorites intruded along the Bau Trend and its intersection with seven parallel, ENE fracture zones, providing channel ways to distribute hydrothermal fluids laterally away from the Bau Trend. Deformation preceding mineralization produced high structural permeability of the host rocks. Central Bau is underlain by an ENE trending, 5x12 km broad plutonic body at depth, inferred from aeromagnetic data. Bau displays district-scale zoning, from proximal porphyry-copper and skarn deposits, via intennediate Cordilleran-Vein base metal mineralization, sediment-hosted precious metal deposits, to distal disseminated Au-As and Ba-Hg-TI deposits. The deposits are hosted in, from proximal to distal, porphyritic granodiorites, limestones, and turbiditic shales. Gradual changes in geochemical, mineralogical, and isotopic compositions across the district indicate consanguinity between them. Epithermal gold mineralization at Bau is most similar to disseminated, sediment-hosted gold deposits of Nevada, except for higher grades, visible occurrence of gold, both base and precious metal signatures, purely structural controls, less radiogenic lead, and magmatic sulfur isotope signatures.

Humic materials were chlorinated with sodium hypochlorite in basic solutions. The varied production of chloroform obtained from these compounds led to an investigation on the structure of humic substances. High pressure hydrogenation of a humic acid utilizing molybdenum-sulfide as a catalyst resulted in only a 26% yield of non-gaseous products. Spectral analysis of the residue indicated it to be composed of a mixture of highly aliphatically substituted aromatic oils. Separation of the components was unsuccessful via conventional techniques. The apparent destruction of the molecule led to an investigation of intact humic substances utilizing nuclear magnetic resonance (NMR). Proton NMR analysis of underivatized humic acids was complicated by the presence of paramagnetic iron. Removal of the iron resulted in poorly defined spectra. ¹³C NMR analysis resulted in absorptions from all the known functional groups of humic acids. The availability of ash free humic and fulvic acids led to the use of basic solutions as solvents in obtaining NMR spectra. The free radical nature of these solutions resulted in a study of ortho-quinone precursors by ¹³C NMR. Broadening of lines, loss of intensity, and shifting or absence of absorptions was noted in the basic ¹³C NMR spectra of catechol, catechin, quercetin, rutin, tannic acid, and fulvic acid when compared to the corresponding neutral spectra. Electron spin resonance studies indicated the existence of a quinone-radical equilibrium in the model compounds. The drastic differences observed upon introduction of the radical perturbs interpretation of ¹³C-NMR spectra on basic solutions of humic substances. Solid-state ¹³C-NMR analysis on humic substances appeared as an auspicious alternative. Magic-angle spinning alone proved useless with all but the most molecularly mobile solids such as polyisoprene. Since hydroxyl functionally plays an important role in the chemical properties of humic substances, derivatization with subsequent ¹³C-NMR analysis of these functional groups was undertaken. A dimethylation procedure utilizing first diazomethane followed by methyl iodide and sodium hydride was found to give complete methylation. This derivatization with ¹³C-enriched methyl precursors labels hydroxyl groups, eliminates hydrogen bonding and enhances signal assignment in the ¹³C-NMR spectra. Estimation of functional group types can also be inferred from integral absorptions. Since this method is direct and nondegradative, ¹³C-NMR relaxation studies can be used to give information on molecular size. The long T₁ values determined on methylated fulvic and humic acids are not characteristic of high molecular weight compounds, but are more appropriate for an aggregate of small units. This procedure completely characterizes hydroxyl functionality in these amorphous molecules and can therefore be used to characterize a whole range of oxygen containing macromolecules such as coal, shale oil, and lignins.

This study reviews the assumptions, the assembled data, and the considerations involved in calibrating a preliminary steady-state model of the City of Tucson's Central Well Field. This study introduces a hydrostratigraphic characterization of basin sediments and develops a new set of aquifer parameter data. The results of two preliminary steady-state calibrations are presented based on assumed steady-state conditions in the early 1900s and quasi-steady-state conditions in 1940. Transient stresses over a 50-year period are imposed onto the results of the 1940 steady-state simulation to identify major deficiencies in the preliminary calibration.

The Cripple Creek district, Colorado is renowned for its epithermal gold telluride veins which have produced over 21 million ounces of gold from an intensely altered alkaline diatreme complex (total production + economic resources of >900 tons Au, geologic resource >>1000 tons). Gold mineralization principally occurs as telluride minerals hosted by swarms of narrow veins composed of quartz ± fluorite, carbonate, adularia, pyrite > barite/celestite and accessory base metal sulfides. Mineralized hydrothermal breccias are also found in the district, along with low-grade, bulk tonnage resources that are targets of current mining activities. Newly recognized is a complex history of hydrothermal alteration and magmatism that led up to, and continued past the development of gold mineralization. These include the development of large volumes of low-temperature, alkali feldspar-rich styles of alteration, and more restricted volumes of high temperature, pyroxene and biotite-rich types. Gold mineralization is associated with voluminous K-feldspar + pyrite ± carbonate alteration that largely postdates igneous activity, and these are widely developed in the upper ∼1000 m of the volcanic complex. These follow a complex magmatic history characterized by at least three cycles of recharge. Although voluminous sulfate (anhydrite) and sulfide-rich styles of mineralization were also developed in the latest stages of hydrothermal activity, a remarkable aspect of Cripple Creek is the distinct underdevelopment of acid styles of alteration; feldspar and carbonate-rich styles of alteration predominate at all levels of exposure. The link between alkaline magmatism and gold deposits has been long recognized, but relatively recent discoveries of large, high grade deposits (Ladolam, Philippines, Porgera, Papua New Guinea), along with continued production from districts like Cripple Creek, encourages continued exploration. Salient characteristics shared by these deposits include telluride-rich mineralization accompanied by extensive carbonation, and voluminous K-metasomatism. Likewise, hydrolytic (acid) alteration tends to be poorly developed in many alkaline systems. This has important environmental implications, as the high acid buffering potential makes these deposits environmentally favorable to mine. The potential in alkaline systems for large and high grade deposits, coupled with the common lack of recognition of their distinctive styles of alteration and mineralization, makes these a compelling exploration target.

The Kootenay Arc in northeastern Washington and southeastern British Colunbia is transitional between: (1) lower Paleozoic autochthonous miogeoclinal strata and Paleozoic to Mesozoic eugeoclinal terranes of uncertain paleogeographic affinity (e.g., the Quesnel terrane): and (2) areas where Devono-Mississippian tectonism was of a compressional nature (Antler Orogeny in central Nevada), and areas in northern British Columbia and southern Yukon Territory where coeval deformation was evidently of an extensional nature. The nature of these transitions was addressed by study of lower Paleozoic eugeoclinal strata comprising the portions of the Kootenay terrane, the most inboard of the terranes in the Canadian Cordillera, and it's contact relations with miogeoclinal strata. Stratigraphic, structural, and U-Pb geochronologic studies focussed primarily on portions of the Lardeau Group in the Trout Lake area in the northern Kootenay Arc and the Covada Group in the southern Kootenay Arc. As a result of these studies, the following concepts are proposed: (1) lower Paleozoic eugeoclinal strata can be correlated along the length of the Arc; (2) these strata are in fault contact with miogeoclinal strata along the length of the Arc: (3) a contractional event of pre-Mississippian and perhaps Devono-Mississippian age is recorded in the Kootenay Arc: (4) despite faulted oontacts, the eugeoclinal strata are parautochthonous and derived from adjacent portions of North America; and (5) structures and stratigraphy in the Kootenay Arc are broadly correlative with those in the Roberts Mountains allochthon in central Nevada. Two important implications of this study, requiring revisions to theories regarding the more general problem of Cordilleran accretion are that: (1) through a series of stratigraphic linkages it can be demonstrated that the Quesnel terrane, a Mesozoic arc-related assemblage often regarded on the basis of faunal evidence to be "exotic", is parautochthonous; and (2) the Antler Orogeny, often regarded as a localized disturbance, affected at least 1200 km of the Cordilleran margin, and perhaps the entire Cordilleran margin.