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Showing 111 to 120 of 120 (0.065 seconds)Spelling suggestions: "subject:"eology -- arizona -- lima county."" "subject:"eology -- arizona -- lima bounty.""
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Structure of Golden Gate Mountain, Pima County, ArizonaAssadi, Seid Mohamad January 1964 (has links)
Golden Gate Mountain appears as a spur projecting westward from the Tucson Mountain range. It is made up of the capping Cat Mountain Rhyolite, the slope - forming Amole Formation, and a variety of intrusions of differing compositions. The emplacement of the andesitic portion of the intrusions occurred during, and probably lasted long after, the deposition of Amole Formation. The hot magma fluidized the wet sediments. Part of the fluidized materials formed pipes and dikes of tuffisites and part was brought up into the basin and contributed to the sedimentation of Amole Formation. During upper Amole time the intrusion of andesite increased in intensity. Part of the basin rapidly subsided and thick deltaic sediments and graywacke were formed. The development of a hinge line accompanied this subsidence. The hinge line controlled the occurrence of fluidization which undercut the Amole beds. The beds slumped into the fluidized parts. The process culminated in forming a large orifice through which the Cat Mountain Rhyolite welled up. The orifice is reflected in the sedimentary beds by the development of a funnel- shaped structure in the central part of which the capping of Cat Mountain Rhyolite is located. The bordering brecciated Amole beds represent the associated slump effects.
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| 112 |
The Geology of the Atlas Mine Area, Pima County, ArizonaAgenbroad, Larry D. January 1962 (has links)
The Atlas Mine is located on the northwest flank of the Silver Bell mountains; Silver Bell mining district, Pima County, Arizona. The deposit is high grade (?) sine-copper mineralization in an altered sedimentary sequence. Rocks in the area include Precambrian (?) alaskite; Permian (?) limestone, quartzite and siltstone; Tertiary (?) monzonite, quartz monzonite, quarts latite porphyry and dacite porphyry; and Quaternary alluvium. The limestone has been largely metamorphosed to a mass of tactite, siltstone has been locally metamorphosed to hornfels, and the quartzite has been silicified, locally shattered and altered. Mineralization is related to NE and E-W trending fault systems, and similarly trending intrusive dikes. Predominate ore minerals are sphalerite and chalcopyrite, associated with pyrite, specular hematite and “high temperature" silicates. Copper mineralization is related to the silicified sediments. Zinc mineralization is present in silicates but is more predominate in areas of recrystallized calcite and extensive garnetization, suggesting incomplete replacement of the original sediments by the silicates. Further exploration and development should be undertaken in areas of favorable structural control, and adjacent to favored intrusives.
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| 113 |
A Geologic-Geochemical Study of the Cat Mountain RhyoliteBikerman, Michael January 1962 (has links)
The main rock unit exposed in the southern part of the Tucson Mountains, Pima County, Arizona, is the Cat Mountain rhyolite. It forms the eastward dipping slope and the western escarpment of the mountain range, capping the large fault blocks which make up the range. Petrographic and radiometric data combine to show that the Cat Mountain rhyolite, as originally defined, consists of two major ash flow eruption sequences. The lower sequence is less uniform and continuous than the highly welded characteristically jointed upper unit. A basal non welded unit is found along the western escarpment, a partly welded transition zone is found between the welded units, and a capping partly-to-non-welded unit is exposed in protected parts of the eastern slope. The volcanic history of the area began with the emplacement of a nuee ardente deposit forming the “chaos” unit. This was followed by two ash flow pulses through the same vents, and the sequence was terminated by the intrusion of spherulitic rhyolite sealing up the vents.
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| 114 |
The partition of trace elements among coexisting minerals in some Laramide intrusive rocks in ArizonaGraybeal, Frederick Turner, 1938- January 1972 (has links)
No description available.
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| 115 |
Kinematic analysis of deformation at the margin of a regional shear zone, Buehman Canyon area, Santa Catalina Mountains, ArizonaBykerk-Kauffman, Ann, Bykerk-Kauffman, Ann January 1983 (has links)
No description available.
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| 116 |
Structural geology and tectonic history of the Geesaman Wash area, Santa Catalina Mountains, ArizonaJanecke, Susanne Ursula, 1959- January 1986 (has links)
No description available.
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| 117 |
Geologic Interpretations of a Siliceous Breccia in the Colossal Cave Area, Pima County, ArizonaAcker, Clement John January 1958 (has links)
In the Colossal Cave area, Pima County, Arizona, massive blocks of Paleozoic sedimentary rocks have been thrust from a southerly direction over an irregular surface of Rincon Valley granite of Laramide age. The Paleozoic rocks involved in the thrusting are the Bolsa quartzite, Abrigo formation, Martin limestone, Escabrosa limestone, Horquilla limestone, and Andrada formation. The Pantano formation (Miocene ?) is also present under the thrust sheet. The thrusting is of an imbricate nature with slip-page mainly teaking place along incompetent rock units. Large folds occur in the Escabrosa limestone and Horquilla lime-stone. A siliceous breccia is associated with thrust planes in the area. The competent units of the Paleozoic sediments were fractured and brecciated along the thrust planes. Solutions dissolved part of the silica and hematite from the Bolsa quartzite and deposited it in the fractured and brecciated zones.
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| 118 |
Stratigraphy of the Permian Rainvalley Formation, southeastern ArizonaVaag, Myra Kathleen January 1984 (has links)
No description available.
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| 119 |
APPLICATION OF STABLE ISOTOPES OF OXYGEN, HYDROGEN, AND CARBON TO HYDROGEOCHEMICAL STUDIES, WITH SPECIAL REFERENCE TO CANADA DEL ORO VALLEY AND THE TUCSON BASIN (GEOCHEMISTRY, ISOTOPE, CARBON-14).CHENG, SONG-LIN. January 1984 (has links)
Hydrogeochemical studies are generally qualitative in nature. The goal of this study is to investigate the possibility of quantitative interpretation of hydrogeochemistry by considering the chemical characteristics and the isotopic compositions of oxygen, hydrogen, and carbon of the water. This study examines ephemeral stream and well waters from Canada del Oro valley, southern Arizona. By chemical and isotopic considerations, this study finds that the change of chemical composition of the wash water was mainly due to water-rock interaction. The concentrations of dissolved constituents increase between 10 to 50% from upstream to downstream samples, while the evaporation loss of water is less than 3%. By chemical and isotopic considerations of the well waters, this study identifies three recharge waters in the CDO ground-water system. The chemical and water isotopic compositions of the well waters are results of mixing between these three recharge waters and subsequent dissolution of the aquifer. By thermodynamic consideration, albite, kaolinite, montmorillonite, and calcite are the main phases that influence the chemical characteristics of this ground-water system. Simulations with the computer program PHREEQE verifies the above conclusions. The mechanisms that influence the chemical and carbon isotopic compositions of the water are quite different in a system open to a CO2 gas reservoir than in a closed system. Deines, Langmuir, and Harmon (1974) derived a set of chemical-isotopic equations to calculate the carbon isotopic composition of water under open system condition. Wigley, Plummer, and Pearson (1978) formulated a mass transfer equation to calculate the change of carbon isotopic composition of natural water in closed system environment. This study implements these two type of equations as a subroutine--CSOTOP to the computer program PHREEQE. With this PHREEQE-CSOTOP package, the evolution of carbon chemical and isotopic composition of natural water can be conveniently modeled from open to closed system conditions. This study also uses this package to date water samples from the Tucson basin, and finds that choice of reaction path may cause a difference in carbon-14 age of up to a few thousand years. This study concludes that it is possible to rigorously interpret hydrogeochemistry in a quantitative way. With sufficient measurements to define the reaction path, followed by thermodynamic consideration, chemical-isotopic evaluation, and computer modeling, one should be able to achieve this goal.
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| 120 |
Stratigraphy and Sedimentology of the Bisbee Group in the Whetstone Mountains, Pima and Cochise Counties, Southeastern ArizonaArchibald, Lawrence Eben January 1982 (has links)
The Aptian-Santonian(?) Bisbee Group in the Whetstone Mountains comprises 2375 m of clastic sedimentary rocks and limestones. The basal Glance Conglomerate unconformably overlies the Pennsylvanian-Permian Naco Group. It consists of limestone conglomerates which were deposited in proximal alluvial fan environments. The superadjacent Willow Canyon Formation contains finer grained rocks which were deposited in the distal portions of alluvial fans. The lacustrine limestones in the Apache Canyon Formation interfinger with and overlie these alluvial fan facies. The overlying Shellenberger Canyon Formation is composed mostly of terrigenous rocks derived from westerly terranes. This formation contains thick sequences of fluvio-deltaic facies as well as a thin interval of estuarine deposits which mark a northwestern extension of the marine transgression in the Bisbee -Chihuahua Embayment. The youngest formation (Upper Cretaceous?) in the Bisbee Group, the Turney Ranch Formation, consists of interbedded sandstones and marls which were deposited by fluvial and marine(?) processes.
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