Current Post-docs and Graduate Students

 Lucy Chapman (Post-doctoral student 2001 - 2004) (Lucy.Chapman@jcu.edu.au)
"Fluid Flow through the Devonian - Lower Carboniferous Upper Old Red Sandstone in the Irish Midlands: Testing Models of Lateral or Vertical Fluid Flow and Implications for the Genesis of the Irish Zn-Pb District"
This study examines the Old Red Sandstone in Ireland to determine its diagenetic history and evaluate the nature and distribution of hydrothermal alteration within the unit. The project aims to determine whether fluid flow in the Old Red Sandstone was of regional extent or the result of flow from point sources. This is being accomplished by detailed logging of continuous drill cores from throughout the Irish Midlands. The project includes isotopic, mineralogic, and fluid inclusion studies of hydrothermal minerals to determine whether systematic lateral variations in mineralogy, isotopic values (C, O, Pb) are observed either regionally or more locally around deposits. (Supported by the National Science Foundation, grant EAR-9908971)


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 Efem Altinok (Ph.D. 2000 - ) (ealtinok@mines.edu)
"Definition of ancient thermophilic microbial activity at the Navan Zn-Pb deposit, Ireland"
This study aims to determine the location of ancient microbial activity at the giant Navan Zn-Pb deposit which contains dominantly biogenic sulfide (see Fallick, A. E. et al., 2001, Economic Geology, v. 96, p. 885-890). The project involves detailed logging and sampling of variably pyritic deep water carbonate turbidites in drill core from above the deposit. Laboratory work includes detailed petrography to determine diagenetic and hydrothermal paragenesis, analyses of biogenic elements (P, Mn, N, C), isotopic analysis of sulfides, and SEM studies to determine the presence of ancient bacteria. (supported by Fogarty Fund - CSM; Tara Mines)
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 David Broughton (Ph.D. 2000 - ) (dbrought@mines.edu)
"Stratigraphy, metamorphism and structure of the Zambian Copperbelt"
Neoproterozoic metasediments of the Katanga Supergroup host the major stratiform Cu-Co deposits of the Central African Copperbelt. The interpreted sedimentological and tectonic setting of these deposits is based on 1940s to 1970s core logging and mapping which does not separate sedimentology, metamorphism, structure and alteration. The resulting "stratigraphy" prevents recognition and evaluation of the relative controls of each of these elements clearly exert on mineralization. This investigation makes use of the large number of deep available drill holes throughout the Zambian Copperbelt. Field research consists primarily of detailed logging of the drill holes focussing on description of sedimentological, metamorphic, structural and metasomatic features and relationships. Representative samples are being selected for petrography, isotopic analysis (including C&O isotopic analysis to derive an isotopic stratigraphy of carbonates similar to that presented by Hoffman et al., (1998) for Namibia), and age dating. (Supported by AMIRA P544)
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 Khitam Alzughoul (Ph.D. 2001 - ) (kalzugho@mines.edu)
"Mineralization in the Whitehorn Stock area, northeast Salida, Central Colorado"
The Late Cretaceous Whitehorn Stock in the Salida area of central Colorado has associated skarn mineralization. Iron was mined from pyroxene-garnet-scapolite skarn at the Calumet Mine. Skarn is developed in the Mississippian Leadville Limestone and the Lower Pennsylvanian Kerber Formation (calcareous shales). This project involves detailed field mapping of the skarn and adjacent intrusion to distinguish the paragenetic sequence of alteration and mineralization events. Detailed mineralogical studies of the skarn will be undertaken through petrography and microanalytical techniques. The presence of abundant scapolite suggests mineralizing fluids were highly saline. This will be investigated through a detailed fluid inclusion study. (Supported by the Jordanian government)
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 Gloria Lopez (Ph.D. 2004 - ) (glopezo@mines.edu)
"Geology and Geochemistry of the El Espino IOCG System, Chile"
The El Espino IOCG prospect is located in the Chilean Coastal Range to the south of other known Chilean IOCG deposits. The prospect area contains a mixed sequence of Lower Cretaceous sedimentary and volcanic rocks. Alteration and mineralization occur mainly in the sedimentary rocks along a regional north-striking fault system. The sedimentary rocks include volcaniclastic siltstones, sandstones, and conglomerates in addition to limestones and gypsum beds. The sedimentary rocks appear to have been deposited in a relatively small (7 km long) marine basin within a major volcanic pile. Contact metamorphism effects are recognized locally in the sedimentary and volcanic rocks. The prospect displays a complex structural history, several alteration events and diverse styles of mineralization. Alteration and mineralization are concentrated mainly in thin-bedded siltstone units, though late epidote-dominated calcic alteration also affects other units. Sodic alteration characterized by albitization accompanies silica replacement. Potassic alteration characterized by K-feldspar appears to be weak and overprints sodic alteration assemblages. Sodic and potassic alteration are overprinted by a complex calcic alteration event consisting of early actinolite-chlorite-(epidote) alteration and later epidote-calcite-(chlorite) alteration. Calcic alteration contains an iron oxide assemblage dominated by specular hematite with lesser mushketovite and magnetite. Chalcopyrite and lesser pyrite are locally intergrown with iron oxides. Iron oxide and sulfide mineralization occurs along NNE to NE-striking faults and NW-striking quartz-calcite veins. Significant strike changes along the fault system correspond to less well-developed alteration and mineralization. This project will investigate the geology and geochemistry of the area and seek to determine if different alteration types are sources or sinks of metals. (Supported by National Science Foundation grant EAR-0207217)
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 Ho Cheol Shin (Ph.D 2004 - ) (hshin@Mines.edu)
"The Geology and Mineralization in the Karmatgai porphyry Cu-Au system, Mongolia"
The Kharmagtai porphyry Cu-Au district is located in the south Gobi Desert in Mongolia. The research area is 500 kilometers south of the capital, Ulaanbaatar. The project area consists of four recognized prospects (Altan Tolgoi, Tsagan Sudal, Zesen Uul and Chun). The host rocks are a volcano-sedimentary sequence of aphanitic tuff, weakly hornblende-phyric andesitic lavas, andesite dykes and andesitic volcaniclastic breccias. These are intruded by a dioritic intrusive complex, which comprises of diorite, quartz diorite and monzodiorite. Quartz-chalcopyrite-pyrite stockwork mineralization is mainly associated with a magnetite-epidote-chlorite alteration assemblage. Tourmaline breccia pipes are a major feature of this area. The project comprises detailed geological mapping, a petrological study and analysis of alteration and mineralization parageneses to elucidate the similarities and differences between each prospect. (Supported by Ivanhoe Mines)

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Jon Woodhead (Ph.D. 2005 - ) (jwoodhea@mines.edu)
"Utilization of Geophysical Datasets to Construct a Comprehensive Geologic Model of the African Copperbelt"
The Central African Copperbelt is the largest sediment-hosted stratiform copper (SSC) district on earth. This project is utilizing modern geophysical data, together with geological data to produce a new geological interpretation of the entire Central African Copperbelt. The project is focused around high-quality airborne geophysical surveys (aeromagnetics and radiometrics) collected by mineral exploration companies over the past decade. These surveys are being compiled and re-processed. Petrophysical data from samples gathered from throughout the area will be utilized to constrain the geophysical modeling. Iterative analysis of the aeromagnetic and radiometric data with regional gravity data and surface geology will be undertaken to create a new geological map of the area together with structurally-balanced, regional cross sections. The project will involve: 1) Production of an integrated GIS database of currently proprietary geophysical and geological data from the Central African Copperbelt which will be available to academic researchers and governmental organizations; 2) Integration of geologic data from the two portions of the Central African Copperbelt (Zambia and Congo) to resolve long-standing questions of lithologic, stratigraphic, and structural correlation; 3) Construction of modern 3-D tectonic and structural models of the region; 4) Elucidation of the the importance of salt tectonics to regional geology and ore genesis; and 5) Integration of the geology of the Central African Copperbelt into the broader context of southern Africa, particularly in respect to the Neoproterozoic-Cambrian Rodinian assembly. The broader societal impacts of the research include providing governmental and non-governmental entities the fundamental scientific data necessary for future mineral development in the region which is critical for renewed economic activity. . (Supported by AngloAmerican and Phelps Dodge Corp.)

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 Bridget A. Ball (M.S. 1999 - ) (bball@mines.edu)
"Petrology of sulfide and PGE-bearing zones in the lower portion of the Lake Owen layered mafic intrusion, Albany County, Wyoming"
This project aims to describe the mineralogic, geochemical, and textural characteristics of sulfide-rich horizons in the lower portion of the Proterozoic Lake Owen layered mafic intrusive complex which is composed of alternating gabbroic and troctolitic rocks. The sulfide-horizons locally contain enhanced PGEs. Cumulus magnetite (locally vanadiferous) is common throughout the lower portion of the intrusion and its relationship to sulfides will also be examined. The project is being accomplished through detailed logging of drill core from Lake Owen, generation of igenous stratigraphic columns emphasizing changes in cumulate chemistry (megascopic and cryptic), and extensive transmitted and reflected light petrography. (Support by Trend Mining Company)

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 Eric Eckberg (M.S. 2004 - ) (coeckbergs@msn.com)
"The Geology of the Gillis Range, Walker River Indian Reservation, western Nevada"

This project involves field mapping in the west central Gillis Range to investigate the stratigraphy, structural geology, and economic geology of the region. The area contains a deformed Meosozoic section of metavolcanic rocks overlain by Triassic limestone. These rocks have been intruded by a variety of intermediate to felsic plutonic rocks of supposed Jurassic to Cretaceous age. The Triassic limestone is locally converted to skarn. Several of the intrusive bodies display stockwork zones of hydrothermal alteration and weak copper and tungsten mineralization. The Mesozoic is unconformably overlain by moderate to steeply dipping Tertiary ash flows of the Yerington group. This project will seek to unravel the complex structural history of the area and utilize this data, together with detailed field mapping of hydrothermal alteration, to determine the region's mineral potential. (Supported by the U.S. Bureau of Indian Affairs.)

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 Tim MacIntyre (M.S. 2004 - ) (tmacinty@mines.edu)
"Alteration and Mineralization of the Wingate Sandstone, Paradox Basin, Utah-Colorado"
The Paradox Basin is a Pennsylvanian half-graben rift that stretches from Utah and Colorado into northern Arizona and New Mexico. It hosts significant oil and gas reserves as well as copper, uranium, and vanadium deposits. The focus of this study is the early Jurassic Wingate sandstone, a gray-tan to brown-red fine-grained cross-bedded eolian sandstone that hosts disseminated copper mineralization around the Paradox and Sinbad salt anticlines in Colorado. This study will focus on the Cashin Mine, a small deposit on the southwest limb of the Paradox Valley anticline. Historically this deposit produced 363,778 oz Ag and 732,740 lbs Cu primarily from luzonite, chalcocite, native copper, and argentite;. Previous workers have identified 2 distinct facies in the Wingate; a red-brown, hematite rich, oxidized facies and a gray-green, pyrite rich, reduced facies that preferentially contains copper. In this investigation we will consider the previously described unaltered (oxidized) facies and bleached (reduced) facies, in addition to the mineralized facies and an unstudied, possibly re-oxidized, (red) facies below the copper mineralization at Cashin. The latest hypothesis to explain alteration and copper mineralization in the Paradox Basin, suggests two episodes of basinal fluid expulsion, one early reducing fluid or gas, likely hydrocarbon, responsible for bleaching, and a later oxidizing brine fluid, responsible for the deposition of copper, silver, and other base metals (Thorson, pers. comm., 2004). This research will: (1) define the spatial extent of bleached and mineralized zones in the Cashin Mine and nearby areas surrounding an upflow zone on the northwest flank of the Paradox anticline; (2) identify the physical and chemical affects of the bleaching and mineralizing fluids; (3) attempt to further constrain the composition of the fluids; and (4) clarify the role of these fluids in ore deposit formation. (Supported by Constellation Copper Corp, with research awards from the Society of Economic Geologists and Rocky Mountain Association of Geologists.)

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Abstracts of Graduate Student Projects (2005 - )

Abstracts of Graduate Student Projects (2002-2004)

Abstracts of Graduate Student Projects (2000-2001)

Abstracts of Graduate Student Projects (1999-1998)

 

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