This report presents the results of a stratigraphic study of the Worm Creek quartzite, the basal member of the St. Charles formation of Upper Cambrian age. The member is present in the Bear River Range, the Malad Range, and the Promontory Range of Northern Utah and southeastern Idaho. The Worm Creek quartzite was differential as the basal unit of the St. Charles formation by Richardson (1913) and named for its occurrence in Worm Creek Canyon in the Bear River Range, Bear Lake County, Idaho.

The Simpson Mountains have long been of economic interest and have renewed interest in their potential value. Field mapping of the project area redefined structural relationships between stratigraphic units. Geometric and kinematic analysis of structures in the Simpson Mountains show the range is deformed by the three most recent tectonic events: the Sevier Orogeny, the Laramide Orogeny, and Basin and Range Extension. Laramide structures define the range with a significant E-W normal fault and an E-W thrust fault, which are both likely related to Eocene-age igneous intrusions. Principal component analysis (PCA) of regional quartzite X-ray Fluorescence (XRF) data resulted in distinctive populations between the Eureka Quartzite and the Mutual and Prospect Mountain Quartzites. The PCA was paired with petrographic analysis of regional quartzites where samples were diagnostically classified to help validate the PCA results. XRF analysis of volcanic rocks show volcanic arc origin. 40Ar/39Ar dating of the volcanic rocks associated with the intrusions yield new ages of 34.09±0.10 to 37.05±0.06 Ma and 19.11±0.02 to 19.18±0.03. Lithostratigraphy of the map area was validated by identification of fossil samples. The Eocene intrusions are likely sources of mineralization in the range along older Sevier structures.

No description available.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on January 15, 2010). Thesis advisor: Dr. Peter Nabelek. Includes bibliographical references.

No description available.

Réalisé en collaboration avec Arkéos Inc. / Ce projet de recherche tente de mieux comprendre le phénomène des supports sur plaquette en quartzite du site ElFs-010 situé en Jamésie. Aucun travail de cette ampleur n’avait encore été réalisé sur ce type d’outil. Il y avait donc un vide à combler. Afin de répondre le plus adéquatement possible à cette problématique, nous avons divisé notre travail en trois objectifs. Dans un premier temps, déterminer si les plaquettes en quartzite sont le produit d’une technologie lithique ou bien d’un processus géologique naturel. En second lieu, démontrer si nous sommes en présence d’un épiphénomène propre au site ElFs-010. Finalement, définir si une période chronologique correspond à cette industrie. Les résultats de nos recherches nous démontrent que les supports sur plaquette en quartzite du site ElFs-010 se retrouvent naturellement sur le talus d’effondrement de la Colline Blanche. Leur faible épaisseur moyenne ainsi que leurs pans abrupts ont sans doute été les facteurs qui ont le plus influencé leur sélection. En nous basant sur ces deux caractéristiques, nous suggérons qu’ils auraient pu être utilisés comme des lames interchangeables ou bien des burins. Nous avons recensé 33 sites jamésiens qui comportaient au moins un fragment de plaquette en quartzite. Malgré quelques indices archéologiques, il est encore trop tôt pour affirmer que cette industrie est diagnostique d’un groupe culturel jamésien. Les données chronologiques suggèrent que cette industrie a connu un essor vers 1300 ans A.A. De plus, il semble que les régions géographiques que nous avons attribuées aux sites correspondent à des séquences culturelles bien définies. Finalement, nos hypothèses portent sur des recherches futures concernant un ensemble d’événements qui, tout comme les supports sur plaquette en quartzite, sont révélateurs de changements dans le mode de vie des groupes préhistoriques de la Jamésie. Mots-clés : Archéologie, Jamésie, ElFs-010, Colline Blanche, plaquette en quartzite, technologie lithique. / This research project seeks to better understand the phenomenon of tabular quartzite tools from the archeological site Elfs-010. No detailed work had yet been carried out on this type of tool, leaving a void to fill. To respond as adequately as possible to this problem, we focused our work on three main objectives. First, determine if tabular pieces of quartzite were the product of a particular lithic technology or of a natural geological process. Second, evaluate whether we are dealing with a unique phenomenon that is specific to site Elfs-010. Third, and finally, define if a specific time period corresponds to this industry. The results of our research show that tabular pieces of quartzite from site Elfs-010 occur naturally on the talus slope of the Colline Blanche. Their low average thickness and their steep sides were probably the factors that most influenced their selection. Based on these two characteristics, we suggest they could be used interchangeably as blades or burins. We identified 33 Jamesian sites that had at least one fragment of tabular quartzite. Despite some archaeological evidence, it is still too early to say that this industry is diagnostic of a Jamesian cultural group. Our chronological data suggest that this industry flourished around 1300 years BP. In addition, it appears that the geographic areas that we have attributed to the sites correspond to culturally well-defined sequences. Finally, our proposed hypotheses for future research concern the events that took place around 1300 years BP and which, like the tabular pieces of quartzite, are indicative of changes in the lifestyle of prehistoric groups of the James Bay region. Keywords: Archaeology, James Bay, ElFs-010, Colline Blanche, tabular pieces, quartzite, lithic technology.

Basée sur un vaste corpus d’œuvres en quartzite, axé sur la statuaire mais prenant aussi en compte d’autres types de monuments, l’étude vise à examiner l’utilisation de cette pierre dure par les anciens Égyptiens au Nouvel Empire, sous les XVIIIe et XIXe dynasties. Correspondant à du grès silicifié, le quartzite a été extrait du Gebel el-Ahmar au nord et des carrières d’Assouan au sud. Après avoir évoqué les caractéristiques géologiques du quartzite et sa désignation dans les anciens textes égyptiens, l’étude traite du travail dans les carrières du point de vue de son organisation et de ses aspects techniques (méthodes d’extraction, outils employés, ébauches in situ), avant d’envisager la question du transport et de la finition dans les ateliers de sculpteurs. La seconde partie, introduite par un chapitre sur l’usage du quartzite avant le Nouvel Empire, est consacrée à l’examen des œuvres du corpus replacées dans leur contexte : il permet de mettre en évidence l’essor de ce matériau au cours de la XVIIIe dynastie, avec une utilisation majeure sous les règnes d’Amenhotep III et d’Akhénaton, fortement marqués par les conceptions solaires, et un nouveau regain sous Séthi Ier, notamment à Héliopolis, et sous Ramsès II qui a cherché à imiter son prédécesseur Amenhotep III. La symbolique solaire du quartzite, due à sa couleur rouge et à l’origine mythique du Gebel el-Ahmar, explique en grande partie son emploi dans les monuments royaux et divins et en fait une pierre de prestige, presque exclusivement réservée à l’élite. Les résultats d’analyses scientifiques menées sur des objets en quartzite du musée du Louvre sont annexés au travail. / Based on a large corpus of works made of quartzite, centred on statuary but also taking into account other types of monuments, the present study is a review of this hard stone use by the ancient Egyptians during New Kingdom, mainly 18th and 19th dynasties. Quartzite or silicified sandstone was extracted from Gebel el-Ahmar quarries in the North and from Aswan quarries in the South. Having mentioned the geologic characteristics of quartzite and its name in the ancient Egyptian texts, the study deals with the work in the quarries (organization and technical aspects like extraction technologies, tools, rough or unfinished pieces found in situ) and the transport of the stone from the quarry to the workshop. The second part of the research, introduced by a chapter on quartzite use before New Kingdom, is dedicated to the monuments of the catalogue put in their context : their examination reveals the significant development of this material during the 18th dynasty, with a peak under the reigns of Amenhotep III and Akhenaton, heavily influenced by solar beliefs, and a revival under Seti Ist (especially in Heliopolis) and Ramesses II, who wanted to emulate his predecessor Amenhotep III. The use of quartzite in royal and divine monuments might be explained by its solar symbolism, due to the red colour of the stone and the mythical origin of the Gebel el-Ahmar : it is the reason why this high-value stone is almost exclusively reserved for the Egyptian elite. An appendix containing the results from scientific analysis conducted on some quartzite objects kept in the Louvre Museum completes the study.

Ce projet de recherche tente de mieux comprendre le phénomène des supports sur plaquette en quartzite du site ElFs-010 situé en Jamésie. Aucun travail de cette ampleur n’avait encore été réalisé sur ce type d’outil. Il y avait donc un vide à combler. Afin de répondre le plus adéquatement possible à cette problématique, nous avons divisé notre travail en trois objectifs. Dans un premier temps, déterminer si les plaquettes en quartzite sont le produit d’une technologie lithique ou bien d’un processus géologique naturel. En second lieu, démontrer si nous sommes en présence d’un épiphénomène propre au site ElFs-010. Finalement, définir si une période chronologique correspond à cette industrie. Les résultats de nos recherches nous démontrent que les supports sur plaquette en quartzite du site ElFs-010 se retrouvent naturellement sur le talus d’effondrement de la Colline Blanche. Leur faible épaisseur moyenne ainsi que leurs pans abrupts ont sans doute été les facteurs qui ont le plus influencé leur sélection. En nous basant sur ces deux caractéristiques, nous suggérons qu’ils auraient pu être utilisés comme des lames interchangeables ou bien des burins. Nous avons recensé 33 sites jamésiens qui comportaient au moins un fragment de plaquette en quartzite. Malgré quelques indices archéologiques, il est encore trop tôt pour affirmer que cette industrie est diagnostique d’un groupe culturel jamésien. Les données chronologiques suggèrent que cette industrie a connu un essor vers 1300 ans A.A. De plus, il semble que les régions géographiques que nous avons attribuées aux sites correspondent à des séquences culturelles bien définies. Finalement, nos hypothèses portent sur des recherches futures concernant un ensemble d’événements qui, tout comme les supports sur plaquette en quartzite, sont révélateurs de changements dans le mode de vie des groupes préhistoriques de la Jamésie. Mots-clés : Archéologie, Jamésie, ElFs-010, Colline Blanche, plaquette en quartzite, technologie lithique. / This research project seeks to better understand the phenomenon of tabular quartzite tools from the archeological site Elfs-010. No detailed work had yet been carried out on this type of tool, leaving a void to fill. To respond as adequately as possible to this problem, we focused our work on three main objectives. First, determine if tabular pieces of quartzite were the product of a particular lithic technology or of a natural geological process. Second, evaluate whether we are dealing with a unique phenomenon that is specific to site Elfs-010. Third, and finally, define if a specific time period corresponds to this industry. The results of our research show that tabular pieces of quartzite from site Elfs-010 occur naturally on the talus slope of the Colline Blanche. Their low average thickness and their steep sides were probably the factors that most influenced their selection. Based on these two characteristics, we suggest they could be used interchangeably as blades or burins. We identified 33 Jamesian sites that had at least one fragment of tabular quartzite. Despite some archaeological evidence, it is still too early to say that this industry is diagnostic of a Jamesian cultural group. Our chronological data suggest that this industry flourished around 1300 years BP. In addition, it appears that the geographic areas that we have attributed to the sites correspond to culturally well-defined sequences. Finally, our proposed hypotheses for future research concern the events that took place around 1300 years BP and which, like the tabular pieces of quartzite, are indicative of changes in the lifestyle of prehistoric groups of the James Bay region. Keywords: Archaeology, James Bay, ElFs-010, Colline Blanche, tabular pieces, quartzite, lithic technology. / Réalisé en collaboration avec Arkéos Inc.

<p>Validerat; 20130508 (global_studentproject_submitter)</p>

As ocorrências estudadas da Sequência da Serra da Boa Vista (SSBV) balizam a borda leste do Quadrilátero Ferrífero nos distritos Santa Rita Durão, Bento Rodrigues e Camargos, da cidade de Mariana até a norte de Catas Altas. Sua geologia e as mineralizações de ouro foram enfocados nessa pesquisa baseada em mapeamento 1:25.000, levantamentos estratigráficos detalhados, estudos mineralógico-petrográficos, litogeoquímicos multielementares e das mineralizações auríferas e de morfologia e microgeoquímica de grãos de ouro e minerais associados via MEV-EDS, visando-se a evolução precambriana e a metalogênese do ouro da SSBV, bem como suas relações com as demais rochas da área, principalmente dos supergrupos Minas e Espinhaço. A área compreende um embasamento arqueano granito-gnáissico TTG em contato milonítico com rochas supracrustais do Greenstone Belt Rio das Velhas (Supergrupo Rio das Velhas) e coberturas paleoproterozóicas dos supergrupos Minas e Espinhaço (anteriormente Série Itacolomi) e da SSBV, com coberturas cenozóicas de canga e alúvio-coluvionares. A SSBV é constituída por quartzitos micáceos com estratificações cruzadas acanaladas de pequeno porte a metaconglomerados, caracteristicamente com fuchsita e sulfetos detríticos, com grânulos a calhaus de metachert e, localmente, de itabiritos. Em menor quantidade e mais restritos ocorrem ainda metaconglomerados polimíticos com seixos de quartzitos, metacherts e itabiritos, magnetita-cloritóide quartzitos com estratificações cruzadas acanaladas de pequeno porte com intercalações de grafita e hematita filitos e turmalinitos, assim como metabrechas intraformacionais itabiríticas. Essas rochas apresentam facies xisto verde predominante, a anfibolito, na parte leste da área. A SSBV desenvolveu-se em uma bacia alongada, de direção geral norte-sul, compartimentada, diretamente sobre o embasamento arqueano, com contribuição quartzosa do complexo gnáissico migmatítico TTG e, possivelmente, dos Metagranitóides Borrachudos (arqueanos), e contribuição detrítica do ouro das rochas do Greenstone Belt Rio das Velhas. A compartimentação da bacia levou à sedimentação de facies distintas - ao menos, no início de sua evolução - reforçada por tectônica sinsedimentar ao longo da deposição; nas facies superiores da SSBV predominam amplamente quartzitos micáceos com lentes de metaconglomerados de grânulos de metachert. O ambiente deposicional remete a uma planície de rios entrelaçados, temporariamente alagada e retrabalhada em ambiente intramaré, com inundação marinha final. O estudo das minas Ouro Fino, Cata Preta e Tesoureiro e do garimpo Fazenda Gualaxo mostrou serem as mineralizações de ouro da SSBV singenéticas, de tipo paleoplacer, com remobilização por veios de quartzo internos ao pacote sedimentar (da SSBV), de origens diagenéticas a metamórficas - de tipo paleoplacer modificado. Os grãos de ouro da SSBV apresentam teores de prata variáveis de até 15%, sem paládio, reforçando a proveniência exclusiva do ouro do Greenstone Belt Rio das Velhas. Os resultados obtidos e as observações nas continuações setentrionais da SSBV, incluindo o garimpo do Morro da Água Quente e as minas históricas de Pitanguí, Quebra Osso até Brumado, apontam para um padrão metalogenético único de mineralizações auríferas singenéticas de tipo paleoplaceres e paleoplaceres modificados, descaracterizados em proporções variáveis por retrabalhamentos tectono-metamórficos policíclicos. O potencial aurífero regional da SSBV é confirmado como elevado e para a sua definição são recomendados estudos específicos prospectivos e de viabilidade econômica. / The Sequência da Serra da Boa Vista (SSBV) stratches in a narrow belt of quartzites and metaconglomerates along the eastern border of the Quadrilátero Ferrífero in the districts of Santa Rita Durão, Bento Rodrigues and Camargos from Mariana, Minas Gerais to north of Catas Altas. The geology and gold mineralizations of the SSBV were studied, based on 1:25.000 mapping, detailed stratigraphical cross sections, mineralogical and petrographical studies, lithogeochemistry, geochemistry of the gold mineralizations and morphology and microgeochemistry of gold grains and associated minerals via SEM-EDS in order to understand better the Precambrian evolution and the metallogenesis of the gold of the SSBV as their as its relationships to other rock units of the region, mainly the Minas and Espinhaço supergroups. The study area comprises an Archean basement of TTG granitic gneisses in mylonitic contact with supracrustal rocks of the Rio das Velhas Greenstone Belt (Rio das Velhas Supergroup) and Paleoproterozoic metasedimentary deposits of the Minas and Espinhaço supergroups (formerly, Itacolomi Series) and the SSBV, with Cenozoic canga and alluvial and colluvial covers. Regionally, greenschist facies metamorphism prevails, grading to amphibolite facies in the eastern part of the area. SSBV consists of micaceous quartzites with small-scale cross-bedding and metaconglomerates with granules and pebbles of metachert and, locally, itabirites, characteristically with fuchsite and detritic sulfides. In smaller amounts and more restricted there occur polymictic metaconglomerates (with quartzite, metachert and itabirite pebbles), magnetite-chloritoid quartzites (with small-scale cross-bedding and intercalations of graphite and hematite phyllites and tourmalinite layers), as well as intraformational itabiritic metabrecchias. SSBV deposits developed directly upon the Archean basement in a narrow, elongate basin oriented and subdivided longitudinally in a north-south direction that received quartzose sediments from the gneissic-migmatitic TTG Complex and possibly from the Archean Borrachudos Metagranitoid; detritic gold came from the Rio das Velhas Greenstone Belt. Initial basin subdivision and ensuing synsedimentary tectonics led to sedimentation of different facies. In the upper part of the SSBV micaceous quartzites with lenses of metachert-granule metaconglomerates predominate. The depositional environment in the basin was a coastal braided river plain with periodic marine incursion accompained by intratidal reworkings and, finally, shallow-marine inundation. The study of the Ouro Fino, Cata Preta and Tesoureiro mines and the Garimpo Fazenda Gualaxo showed the gold mineralizations of the SSBV to be syngenetic, of paleoplacer and modified paleoplacer types with diagenetic to metamorphic remobilization (quartz veins) within the sedimentary sequence. Gold grains of the SSBV show variable silver contents up to 15%, without palladium, demonstrating the exclusive provenance of the gold from the Rio das Velhas Greenstone Belt. Results and observations in the northern SSBV, including the Garimpo do Morro da Água Quente and the Pitanguí and Quebra Osso-Brumado historic mines, indicate a homogeneous metallogenetic pattern of syngenetic gold mineralizations of paleoplacer and modified paleoplacer types, obliterated in varying proportions by tectono-metamorphic polyciclic reworkings. This study confirms the high regional gold potential of the SSBV and recommends specific prospective studies and economic viability analyses for its more complete definition.