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Thesis (Ph. D.)--University of Sydney, 2002. / Title from title screen (viewed Apr. 23, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Geosciences, Division of Geology and Geophysics. Degree awarded 2002; thesis submitted 2001. Includes bibliography. Also available in print form.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 152-167). Also available via the Internet.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, for the degree of Doctor of Philosophy / This thesis provides a comprehensive account of the geology of the Archaean granitoid-greenstone terrane centred around Three Sisters in the northeastern sector of the Barberton Mountain Land. The supracrustal succession in the region comprises a diverse variety of altered volcanic and sedimentary rock types that have been correlated with the principal lithostratigraphic units of the Barberton greenstone belt (BGB) as fellows: 1) schistose basic and ultrabasic lithologies correlated with the Theespruit Formation of the Gnverwacht Group are mainly developed in a narrow unit fringing the northern margin of the BGB; 2) ferruginous shale greywacke - banded iron-formation assemblages correlated with the Jheba and Belvue Road Formations constitute the dominant Fig Tree Group imks in the region. A sec «ence or silicic » .-stavolcaniclastic rocks, now altered to a variety of micaceous schists, occurs west, north ar.a northeast of Three Sisters. Viljoen and Viljoen (1970) cc rrela ted these schists ith the Theespruit Formation. In this study, the schists have been assigned'to a new lithostratigraphic unit, referred to as the Bien Venue Formation, which forms the uppermost formation of the Fig Tree Group in the northeastern part of the BGB. Isotopic studies on zircons indicate that the schists have an age of 3256 ± Ma, which is some 200 Ma younger titan the most recent age estimates for the lower portions of the Gnverwacht Group. Chemically, the silicic schists resemble calc-alkaline rocks found in modem arcs, suggesting that the Bien Venue Formation represents a period of arc-like volcanism; and 3) conglomeratic and quartzitic rocks constitute the dominant lithologies within the Moodies Group, which uncoriorroably or paraconformably overlies lithologies of the Fig Tree and Onverwacht Groups. North of the BGB is a complex suite of granitoid rocks, previously investigated by Robb et al. (1983) who defined a large (—60 kn ng and —6 km wide), elongate plutonic body of tonalitic-to-trondhjemitic composition known as the Stentor pluton. It was suggested that this pluton is correlatable with the irondhjemite gneiss plutons that intrude the southwestern parts of the BGB. Field evidence indicates, however, that the Stentor pluton forms a much smaller (* .14 km long and ~ 4 km wide) ovoid body located immediately north of the village of Louw’s Creek. Furthermore, the pluton consists of equigranular-textured graiodiorite-adamcllite, totally unlike any of the trondhjemite gneisses. In terms of texture, mineralogy and chemical composition, the Stentor pluton closely resembles the Hebron and Berlin plutohs which constitute a phase of the Nelspruit batholith. Thus, it is concluded that the Stentor pluton also forms an integral part of the batholith. Three deformation phases have been identified. The regional event affected all stratigraphic units in response to a northerly oriented compressions! stress and gave rise to east-northeasterly trending, tight-.« 5soclinal, upright and north-verging folds that are bounded by southward-dipping longitudinal reverse faults. The regional deformation occurred both prior and subsequent to the emplacement of the Stentor pluton at circa 3100 Ma. Deformation associated with the diapiric intrusion of the Stentor pluton into the greenstone assemblage during the regional deformation pnase, led to the formation of large-scale folds that have modified earlier formed structures. The final deformation episode is manifested by the presence of nortnwest- to northeast-striking, oblique-slip normal faults that exhibit both left- and right-lateral strike-slip components. / AC 2018

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, for the degree of Doctor of Philosophy / This thesis provides a comprehensive account of the geology of the Archaean granitoid-greenstone terrane centred around Three Sisters in the northeastern sector of the Barberton Mountain Land. The supracrustal succession in the region comprises a diverse variety of altered volcanic and sedimentary rock types that have been correlated with the principal lithostratigraphic units of the Barberton greenstone belt (BGB) as fellows: 1) schistose basic and ultrabasic lithologies correlated with the Theespruit Formation of the Gnverwacht Group are mainly developed in a narrow unit fringing the northern margin of the BGB; 2) ferruginous shale greywacke - banded iron-formation assemblages correlated with the Jheba and Belvue Road Formations constitute the dominant Fig Tree Group imks in the region. A sec «ence or silicic » .-stavolcaniclastic rocks, now altered to a variety of micaceous schists, occurs west, north ar.a northeast of Three Sisters. Viljoen and Viljoen (1970) cc rrela ted these schists ith the Theespruit Formation. In this study, the schists have been assigned'to a new lithostratigraphic unit, referred to as the Bien Venue Formation, which forms the uppermost formation of the Fig Tree Group in the northeastern part of the BGB. Isotopic studies on zircons indicate that the schists have an age of 3256 ± Ma, which is some 200 Ma younger titan the most recent age estimates for the lower portions of the Gnverwacht Group. Chemically, the silicic schists resemble calc-alkaline rocks found in modem arcs, suggesting that the Bien Venue Formation represents a period of arc-like volcanism; and 3) conglomeratic and quartzitic rocks constitute the dominant lithologies within the Moodies Group, which uncoriorroably or paraconformably overlies lithologies of the Fig Tree and Onverwacht Groups. North of the BGB is a complex suite of granitoid rocks, previously investigated by Robb et al. (1983) who defined a large (—60 kn ng and —6 km wide), elongate plutonic body of tonalitic-to-trondhjemitic composition known as the Stentor pluton. It was suggested that this pluton is correlatable with the irondhjemite gneiss plutons that intrude the southwestern parts of the BGB. Field evidence indicates, however, that the Stentor pluton forms a much smaller (* .14 km long and ~ 4 km wide) ovoid body located immediately north of the village of Louw’s Creek. Furthermore, the pluton consists of equigranular-textured graiodiorite-adamcllite, totally unlike any of the trondhjemite gneisses. In terms of texture, mineralogy and chemical composition, the Stentor pluton closely resembles the Hebron and Berlin plutohs which constitute a phase of the Nelspruit batholith. Thus, it is concluded that the Stentor pluton also forms an integral part of the batholith. Three deformation phases have been identified. The regional event affected all stratigraphic units in response to a northerly oriented compressions! stress and gave rise to east-northeasterly trending, tight-.« 5soclinal, upright and north-verging folds that are bounded by southward-dipping longitudinal reverse faults. The regional deformation occurred both prior and subsequent to the emplacement of the Stentor pluton at circa 3100 Ma. Deformation associated with the diapiric intrusion of the Stentor pluton into the greenstone assemblage during the regional deformation pnase, led to the formation of large-scale folds that have modified earlier formed structures. The final deformation episode is manifested by the presence of nortnwest- to northeast-striking, oblique-slip normal faults that exhibit both left- and right-lateral strike-slip components. / AC 2018

The golden generation have a wealth of experience and knowledge from throughout their lifetimes that younger generations wish to retain. In our technology filled world an obvious means of collecting this information is electronically. Digital library col- lections are increasingly used by libraries and large institutions to record their large amounts of information but they can also be used for personal collections. Seniors are often willing and keen to impart their years of experience upon people of the younger generation but time is not always on their side as they grow older. Throughout a lifetime a person could collect large amounts of papers, diaries, pho- tos and media but the time it takes to organise these documents can be long and exhausting and the person's health is not always at its best in old age. Greenstone is a suite of software for creating digital libraries, which are organised collections of documents. Greenstone has the ability to distribute collections either using a server or CD-ROM, and provides advanced searching and organization tools. While Greenstone is a versatile and useful tool in creating digital collections, its in- terface is not designed for senior users. Seniors are commonly perceived to have more physical and mental disadvantages as they get older. These disadvantages can dramatically affect how usable seniors find a piece of software. The aim of this thesis is to investigate how usable the current Greenstone interface is for use by seniors and to re-design the interface so that Greenstone may be more easily used by senior users. This thesis focuses upon what types of documents and descriptive data seniors would like to include in a collection about their life. This is to ascertain exactly what parts of the interface must be improved when it comes to metadata and classifiers. The results of this investigation also helped in the creation of a customised metadata set for senior users use.

The ca. 2720 Ma Vermilion, Shebandowan, Winston Lake, and Manitouwadge greenstone belts (VGB, SGB, WGB, and MGB, respectively) are located along the northern margin of the Wawa subprovince. They are interpreted to have formed in broadly similar rifted arc to back-arc environments, but their base and precious endowment and, in particular, their endowment in VMS deposits, differ markedly. These difference is metal endowment reflect differences in their metallogenic history that were examined by comparing their regional, belt-scale lithostratigraphy, chemostratigraphy, petrogenesis and tectonic history constrained by new U-Pb zircon geochronology. The MGB is the most VMS-endowed and isotopically juvenile (Pb and Nd) greenstone belt. It has a trace element chemostratigraphy that is consistent with a rifted arc to back-arc environment. The trace element chemostratigraphy of the WGB is also consistent with a rifted-arc to back arc geodynamic setting. The Winston Lake VMS deposits formed during early rifting of the arc and their timing is tightly constrained at ca. 2720 Ma by U-Pb ages of the host felsic strata and post-VMS Zenith gabbro. The Zn-dominated VMS mineralization formed from hydrothermal fluids that were <300 ° and were possibly boiling in relatively shallow water. The trace element chemostratigraphy of the VGB, SGB, and WGB indicates a plume-driven rifted arc to back-arc geodynamic settings. The composition of VMS mineralization, lithofacies, and alteration in these belts are consistent with a relatively shallower-water environment, which may have compromised VMS formation. The high-Mg andesites that are typical of, but restricted to, the SGB formed during compressional “hot” subduction, which resulted in the development of a thicker arc crust. This thicker crust may have inhibited VMS formation, but favoured the formation of magmatic sulphide and gold mineralization. New detrital and magmatic zircon U-Pb geochronology allowed comparison and correlation of lithostratigraphy and metallogeny between the greenstone belts. U-Pb ages within the VGB also defined younger, Timiskaming-type volcanic and sedimentary strata that are coeval with similar deposits in the SGB. These strata are spatially and temporally associated with gold mineralization in both belts and are coeval with similar deformation and magmatic events in the WGB and along the northern margin of the Wawa-Abitibi terrane. This indicates that the formation of Timiskaming-type pull apart basins in the northern part of the Wawa-Abitibi terrane were synchronous, and earlier than in the southern part, which is consistent with oblique convergence of the Wawa-Abitibi terrane onto the Superior Province. Detrital zircon geochronology also revealed the presence of a >2720 Ma iv zircon population within the Timiskaming-type sedimentary strata of the SGB. This is consistent with their derivation from the Wabigoon subprovince and suggests trans-terrane transport of detritus in a foreland –type basin resulting from uplift of the Wabigoon subprovince during accretion of the Wawa subprovince.

Orientador: Elson Paiva de Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-08-08T17:16:45Z (GMT). No. of bitstreams: 1 DonattiFilho_JosePaulo_M.pdf: 3208335 bytes, checksum: 9cc1b1de3c939ba63d65e7dde4caea9b (MD5) Previous issue date: 2007 / Resumo: O Greenstone Belt Paleoproterozóico do Rio Itapicuru, nordeste do Cráton do São Francisco, está inserido integralmente no Bloco Serrinha e possui um domínio vulcânico máfico com um contexto geodinâmico de formação em debate, se arco, bacia de retro-arco ou rifte intracontinental. Dados geoquímicos dos basaltos deste domínio foram obtidos com o intuito de reavaliar a geoquímica e o contexto tectônico de formação dessas rochas com base principalmente na geoquímica de elementos-traço de elevado poder interpretativo (e.g. Low Field Strenght Element (LFSE), High Field Strenght Element (HFSE), e Rare Earth Element (REE)). Este domínio é composto de lavas almofadadas, basaltos variolíticos, basaltos maciços e porfiríticos, bem expostos no curso médio do Rio Itapicuru. A paragênese metamórfica indica condições variando de fácies xisto verde a fácies anfibolito. O domínio é composto basicamente por basaltos Fe-toleíticos subalcalinos, que são divididos geoquimicamente em dois grupos: ThI ¿ enriquecidos em Ti-P e elementos-traço incompatíveis, e outro, representado pelos toleiítos tipo II (ThII) que exibem baixas concentrações nesses elementos. Os ThII são mais primitivos geoquimicamente, exibindo valores relativamente mais elevados em Mg, Ni e Cr. Espacialmente os dois grupos distribuem-se em dois domínio distintos, um a leste (ThI), e outro a oeste (ThII). O enriquecimento seletivo e a alta mobilidade de alguns elementos litófilos (e.g. Rb, Ba, Na, Cs) indicam que os basaltos passaram por processos de metassomatismo em ambiente oceânico. A lacuna composicional entre elementos incompatíveis dos dois grupos (e.g. P, Ti, Zr, Th, Nb) indica que a petrogênese não pode ser explicada por cristalização fracionada isoladamente. Provavelmente, diferentes estágios de fusão parcial seguido de cristalização fracionada foram suficientes para gerar líquidos basálticos distintos. A modelagem geoquímica sugere taxas de fusão variando entre 10-25% de uma mesma fonte sublitosférica (LaN/NbN =1) sem a presença de granada (LaN/LuN ~1). A composição sugerida da fonte mantélica dos basaltos foi um lherzolito ou plagioclásio lherzolito, que passou por um primeiro estágio de fusão (10-15%) dando origem aos ThI, e sucessivamente um segundo estágio de fusão (15-25%) que gerou os ThII. A presença de uma nítida anomalia negativa de Nb e a semelhança geoquímica com basaltos continentais (e.g. Paraná e Deccan), indicam uma significante assinatura crustal. Os resultados geoquímicos de elementos-traço sugerem para os basaltos do Greenstone Belt do Rio Itapicuru uma semelhança petrotectônica com basaltos transicionais (T-MORB) de ambiente continental a oceânico, similar nos dias de hoje com a margem continental Atlântica / Abstract: The Paleoproterozoic Rio Itapicuru Greenstone Belt, situated in the Serrinha Block - northeast São Francisco Craton, has a sequence of basaltic rocks whose tectonic setting is under discussion, i.e whether a back arc setting or intracontinental rift. The basalt geochemistry was revisited on the basis of incompatible trace elements data, such as high field strength elements (HFSE), low field strength element (LFSE) and the rare earth elements (REE). The basalts are well exposed along the Itapicuru River where the study is concentrated. They are composed of massive and pillowed flows with occasional variolitic to porphyritic structures; they show metamorphic paragenesis indicative of greenschist to amphibolite facies. The basalts are essentially Fe-rich tholeiites that can be separated into two groups: ThI ¿ with high abundances of Ti-P and other trace elements, and ThII ¿ with low abundances of Ti-P and other trace elements. The ThII group is geochemically more primitive than ThI and is relatively enriched in compatible elements (e.g. Mg, Ni e Cr) and show higher mg-number. The two basalt groups crop out in geographically distinct areas: ThI dominates in the eastern part of the basalts exposure area, whereas ThII is restricted to the western part of it. Selective enrichment in some large ion lithophile elements (LILE), such as Rb, Ba, Na and Cs indicates that the basalts were affected significantly by postmagmatic processes (low-grade metamorphism and ocean water interaction). The large variation of some trace element ratios (e.g. Ti, P, Zr, Nb, Th), indicate that the two basalt groups cannot be linked by fractional crystallization of a single parental magma. Instead, the two groups are likely to have derived from liquids resulting from different degrees of partial melting from a similar mantle source, followed by shallow level fractional crystallization. Geochemical modelling suggests melt rates around 10-25% of the same lithospheric mantle source (LaN/NbN = 1), with no garnet in the residue (LaN/LuN ~ 1). The suggested source is a lherzolite or plagioclase lherzolite that experienced a first stage of partial melting (10-15%) to give the ThI, and later the ThII group by higher partial melting rates (15-25%). The negative Nb anomaly on mantle-normalised multi-element diagrams and the geochemical similarities with continental flood basalts (e.g. Paraná and Deccan) indicate a significant crustal signature. The combined mode of field occurrence and the trace-element data indicate petrotectonic similarities with transitional-type basalts, thus rendering support to a tectonic setting transitional between continent and ocean, probably similar to the present-day Atlantic continental margin / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

M.Sc. / Please refer to full text to view abstract