Show simple item record

dc.contributor.advisorHitzman, Murray Walter
dc.contributor.advisorGysi, Alexander
dc.contributor.authorHurth, Michael J.
dc.date.accessioned2017-07-20T19:38:25Z
dc.date.accessioned2022-02-03T13:00:16Z
dc.date.available2017-07-20T19:38:25Z
dc.date.available2022-02-03T13:00:16Z
dc.date.issued2017
dc.identifierHurth_mines_0052N_11299.pdf
dc.identifierT 8312
dc.identifier.urihttps://hdl.handle.net/11124/171147
dc.descriptionIncludes bibliographical references.
dc.description2017 Summer.
dc.description.abstractLarge iron oxide occurrences have long been recognized in the Neoproterozoic Katangan and Damaran Supergroups of southern Africa, and in the Central African Copperbelt (CACB) these iron oxide occurrences are commonly associated with significant base metal deposits. However, no detailed comparative study of these iron occurrences has previously been conducted, and their relationship to base metal deposits was poorly understood. This is a two-part study, where the primary objective of the first study was to document the hitherto poorly known geology of the Xaudum iron ore prospect in northwest Botswana, one of the largest iron oxide deposits in the region. The second study is a comparison of twelve iron occurrences in the CACB, one in the Kaokoland region of Namibia, and one at Xaudum that was conducted to provide insights into their genesis and to elucidate their relationship to base metal deposits. A combination of geological data from drill core logging and field mapping were integrated with geophysical and drill core assay data to delineate key geologic characteristics at the individual prospects or deposits. Mineralogical and textural observations from optical microscopy of over 140 thin sections, scanning electron microscopy (SEM), and automated mineralogy were combined with geochemical bulk rock and isotopic (δS34, δC13, δO18) analyses to further constrain their genetic relations. The iron occurrence at the Xaudum iron ore prospect consists of two stratiform magnetite-rich horizons hosted within Sturtian Grand Conglomérat Formation diamictites, which have been deformed and metamorphosed to amphibolite facies. The different magnetite-rich units within the potential ore horizons display distinct spatial trends in thickness and mineral abundance relative to the apparent synsedimentary fault-bound paleohighs. These faults appear to also have acted as conduits for hydrothermal fluids responsible for a latter sodic alteration event. Textural relationships and bulk rock geochemical data suggest that the potential iron ore horizon consisted of a pre-metamorphic mineral assemblage of iron oxide-cryptocrystalline quartz-ankerite-dolomite with minimal argillaceous material and units that had a pelitic protolith with disseminated magnetite. Iron occurrences in the CACB at Chafaguma Hill, Kansanshi, Fishtie, and Kamoa in the are also associated with the Grand Conglomérat Formation diamictites while those in Kaokoland in Namibia are associated with the Chuos Formation diamictites. These deposits form stratigraphic units that typically have strike lengths >10 km, occur on paleobasin margins, and except for Kamoa, are interpreted to have a pre-metamorphic protolith consisting of iron oxide minerals and quartz ±ferroan carbonates. These deposits are typically conformably laminated or banded and may contain diamictites and schists with disseminated iron oxides. Textural and contextual evidence suggests that these deposits formed as chemical sediments that are potentially linked to hydrothermal activity and to the unique seawater chemistry present during the Sturtian Glacial event. They can be classified as Rapitan-type iron deposits. Iron occurrences in the CACB at Konkola, Kipushi East, Kabolela, Bangwe, Mukondo, and Mulenga occur below the Grand Conglomérat Formation diamictites in upper Roan Group rocks within or adjacent to halokenetic breccias. They typically occur in the paleobasin centers, have strike lengths <4 km, and are stratabound, but may be highly irregular in shape. Iron oxides in these deposits commonly display iron oxide-rich veins and replacive textures. These iron occurrences may have analogies to modern day brine seeps in the Gulf of Mexico and the Red Sea or in the subsurface where brines were focused along the edges of halokenetic salt bodies. In the CACB, iron mineralization preceded copper mineralization. Several iron occurrences, in different stratigraphic and structural settings, were found to have served as precipitation sites for the later sulfide mineralization events. Copper deposits occur stratigraphically below or are intercalated with iron-mineralized strata at every studied locality. Commonly, the iron occurrences and base metal deposits appear to be genetically related to the same structures. Thus, the location of an iron occurrence can provide an additional tool for base metal exploration in the CACB.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2017 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectCentral African Copperbelt
dc.subjectironstone
dc.subjectXaudum
dc.subjecteconomic geology
dc.subjectbanded iron formation
dc.subjectNeoproterozoic
dc.titleGeologic investigation of iron occurrences in the Katangan and Damaran successions of southern Africa: a comparative study
dc.typeText
dc.contributor.committeememberEmsbo, Poul
dc.contributor.committeememberPlink-Björklund, Piret
thesis.degree.nameMaster of Science (M.S.)
thesis.degree.levelMasters
thesis.degree.disciplineGeology and Geological Engineering
thesis.degree.grantorColorado School of Mines


Files in this item

Thumbnail
Name:
Hurth_mines_0052N_11299.pdf
Size:
15.98Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record