Thesis (M.Sc.)--Acadia University, 2001. / Includes bibliographical references (leaves 151-156). Also available on the Internet via the World Wide Web.

Thesis (M.S.)--University of Nevada, Reno, 2006. / "December, 2006." Includes bibliographical references (leaves 55-60). Online version available on the World Wide Web.

M.Sc. / A prominent zone of deformation, identified as a possible hydrothermal fluid pathway, has recently been discovered by the author in the 64 SW4 21Line workings at Kopanang Gold Mine. The zone is between 3m and 16m wide, has a NE SW trend and dips steeply (65°-70۫°) towards the SE. Very little to no displacement seems to occur along this zone of alteration that is marked by intensive albite veining; the surrounding host rocks are also intensively altered (albitized). Albitization resulted from sodium metasomatism, during which Na was exchanged for K, and was accompanied by quartz dissolution which resulted in vug formation. This alteration event is also characterized by REE enrichment, which was found to be most intense in carbonate (ankerite) rich albitized vein fill material. A study of fluid inclusions indicates that the main hydrothermal fluid was of relatively low salinity (14.46 to 19.84 wt% NaCl ), having homogenization temperatures between 59.6 and 117°C. From these measurements it was concluded that a likely emplacement temperature for the studied feature would be in the order of 200°C-300°C at a pressure of roughly 0.5 to 1Kbar. A marked increase of Au grades is observed where the Vaal Reef, the most important economical reef horizon exploited at the mine, is affected by deformation, veining, and associated alteration. In light of the above observations it appears only reasonable to expect that this zone of deformation and hydrothermal alteration could either be the direct cause of, or at least have a prominent influence on the high gold values occurring in the area. A causal link between high Au grades, deformation and hydrothermal fluid flow would have obvious economic implications. The study therefore strives to characterise the extent and style of deformation, constrain the effects of hydrothermal alteration and nature of hydrothermal fluids associated with the structure, and assess its importance for Au mineralization

No description available.

The Pozzolane Rosse ignimbrite [PR] (457±4 ka) in the Alban Hills Volcanic District, Rome, Italy was exposed ~ 40 ka prior to a subsequent volcanic event which coverd it entirely. XRF, XRD, and clay separation results from PR samples from INGV and CA1 boreholes and Castel di Leva quarry show evidence of paleopedogenesis. All locations display loss of base cations, loss of K is consistent with XRD datat showing dissolution or alteration of leucite to analcime. Accumulation of Al and high L.O.I. support XRD evidence of 1:1 clay species at upper depth. Data suggest alteration extent can be determined by geochemistry. Hydrothermal alteration is assessed from geochemistry showing significant leaching of major and trace elements, primary mineralogy loss and iron sulfide and sulfate mineral development. Deep samples of PR may show groundwater influenced alteration with the presence of expandable 2:1 clays, zeolites, and possible mixing with the underlying Vallerano Lava.

Veins and pervasive wall-rock alteration composed of coarse muscovite +/- quartz +/- pyrite are documented for the first time in a porphyritic granite at Luhr Hill in the Yerington District, Nevada. Coarse muscovite at Luhr Hill occurs at paleodepths of similar to 6-7 km in the roots of a porphyry copper system and crops out on the scale of tens to hundreds of meters, surrounded by rock that is unaltered or variably altered to sodic-calcic assemblages. Coarse muscovite veins exhibit a consistent orientation, subvertical and N-S striking, which structurally restores to subhorizontal at the time of formation. Along strike, coarse muscovite veins swell from distal, millimeter-thick muscovite-only veinlets to proximal, centimeter-thick quartz-sulfide-bearing muscovite veins. Crosscutting relationships between coarse muscovite veins, pegmatite dikes, and sodic-calcic veins indicate that muscovite veins are late-stage magmatic-hydrothermal features predating final solidification of the Luhr Hill porphyritic granite. Fluid inclusions in the muscovite-quartz veins are high-density aqueous inclusions of similar to 3-9 wt% NaCl eq. and < 1 mol% CO2 that homogenize between similar to 150 and 200 A degrees C, similar to fluid inclusions from greisen veins in Sn-W-Mo vein systems. Our results indicate that muscovite-forming fluids at Luhr Hill were mildly acidic, of low to moderate salinity and sulfur content and low CO2 content, and that muscovite in deep veins and alteration differs in texture, composition, and process of formation from sericite at shallower levels of the hydrothermal system. Although the definition of greisen is controversial, we suggest that coarse muscovite alteration is more similar to alteration in greisen-type Sn-W-Mo districts worldwide than to sericitic alteration at higher levels of porphyry copper systems. The fluids that form coarse muscovite veins and alteration in the roots of porphyry copper systems are distinct from fluids that formed copper ore or widespread, shallower, acidic alteration. We propose that this style of veins and alteration at Luhr Hill represents degassing of moderate volumes of overpressured hydrothermal fluid during late crystallization of deep levels of the Yerington batholith.

Northern Norrbotten County is one of the three major ore producing districts in Sweden. Based on the predominance of epigenetic Cu-Au and Fe-oxide mineralization this region is regarded as a typical IOCG province. The massive to layered Viscaria Cu-deposit is proposed to be a VMS deposit of Besshi-type and is unique in deposit type of the region. The volcaniclastic rocks of the Viscaria Formation hosting the Viscaria deposit belong to the rift related Kiruna Greenstone Group. The Viscaria deposit consists of three stratiform-stratabound mineralized zones: A-, B- and D-zone. Sulphide mineralization of the D-zone differs in structural features, host rock, mineralization style and Fe-oxide dominance over Cu-sulphides compared to the main Cu-ore in the A-zone. These differences between A- and D-zone mineralization styles raise the subject that the D-zone could be of a different origin.   The Kiruna area is mainly covered by glacial-till, which contributes to limited bedrock exposure. This becomes a challenge when exploring for new deposits and highlights the importance of good geological knowledge obtained from existing deposits to carry through successful exploration programs. The objective of this study is to characterize the Fe-Cu-occurrence and the associated alteration halo of the Viscaria D-zone. Alteration halos can reach several kilometres away from the main ore zone and provides mineralogical and chemical signatures that extend the target area significantly in exploration for new deposits. Detailed core logging, optical microscopic studies, lithogeochemistry and electron microprobe analyses was utilized to contribute to a better genetic understanding of the D-zone and the associated hanging wall and footwall alteration features. The study shows that the main ore minerals of the D-zone consist of magnetite and chalcopyrite, and minor pyrite and hematite. The major alteration minerals associated with mineralization are calcite, actinolite/tremolite, epidote, chlorite and also biotite and scapolite in the hanging wall. The most prominent potential ore vector is calcite veins and biotite, as the abundance increase towards the D-zone. D-zone are further characterised by low REE concentrations, similarly to the calcic-dolomite host. The study also shows that the alteration halo of the D-zone is different in the hanging wall compared to the footwall, which is confirmed by the lithogeochemistry and mineral chemistry. The footwall is characterized by spilitization and chlorite alteration. The lithogeochemistry of the D-zone and the hanging wall reveals element mobility of Mg, Ba, Fe, Na, K, Cu and Zn. Mineral chemistry of epidote, amphibole and chlorite shows chemical changes in Fe/Al- and Mg/Fe-ratios. According to the result of this thesis and earlier studies, the D-zone mineralization is suggested to be part of the VMS system forming the stratigraphically above laying A-zone of the Viscaria Cu-deposit.

Various traumatic events such as automobile accidents, structure fires, or terrorist attacks result in traumatic and thermal injury. Fire is a destructive force that can alter or destroy evidence, and thermal alterations have negative effects on forensic and anthropological recovery and analysis. Blunt force trauma is particularly difficult to analyze because of the multiple ways in which this trauma appears on a body and the variety of objects that can impact and fracture a bone or the variety of ways a body can impact a blunt surface. As fire is a common way to cover up a crime and blunt force trauma is used as a means to kill or injure an individual, it is necessary to understand the differences between these two types of fractures that can present together on bone. The present study was performed to determine the amount of survivability of traumatic fracture patterns in remains that have been exposed to a burning event. The sample used for this investigation was composed of twenty limbs (forty long bones) from five full-grown, domestic, female sheep (Ovis aries) obtained from a farm in Connecticut. Thirty specimens were traumatized with the head of an Estwing ball peen hammer and ten were left as controls. After specimens were subjected to blunt force trauma, each was radiographed using Computed Tomography. They were then placed in a small structure, 8' x 8', that was constructed to simulate the conditions of a house fire. Each post-burn bone was analyzed based on a number of characteristics. A trauma score of "1" no trauma, "2" ambiguous, and "3" traumatic fractures were given based on these observations. CT scans were examined after bone samples had been analyzed. Again, each specimen's CT scan was given a trauma score ("1" no trauma, "2" ambiguous, and "3" traumatic fractures). Results from the bone analysis on the 30 traumatized and burned specimens revealed that 15 did not have trauma, 2 were ambiguous (i.e., they may have trauma but traumatic characteristics were not distinct), and 13 presented with distinguishable traumatic injury. Comminuted was the most prominent type of fracture, and the next most common fracture was oblique. The majority of traumatic injury was found on the middle portion of the bone. CT examination showed that 12 specimens had suffered traumatic injury. The two analyses were compared and showed an agreement of 83.3% between the trauma scores. Results show that differentiation of traumatic and thermally induced fractures is possible using various fracture characteristics as well as taphonomic indicators to determine the sequence of events.

Made available in DSpace on 2014-06-11T19:22:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-10-10Bitstream added on 2014-06-13T19:48:32Z : No. of bitstreams: 1 limberger_l_me_rcla.pdf: 1317800 bytes, checksum: d5ac384a4add401279c2765a7da9114c (MD5) / O presente trabalho tem por objetivo caracterizar o clima da região oeste de Paraná e fazer uma relação deste com a presença do lago artificial da Usina Hidrelétrica de Itaipu, formado em 1982, bem como a percepção climática dos moradores da região em relação à presença do lago e suas influências no clima local. Isso torna-se importante visto que, em geral, o clima local é bastante influenciado por ações antrópicas; no reservatório de Itaipu houve o armazenamento de 29 bilhões de metros cúbicos de água, inundando um total de 1.350 km2 de área, atingindo 15 municípios no oeste do Paraná, e um no estado do Mato Grosso do Sul, ocasionando uma grande alteração na paisagem. Para atingir o referido objetivo trabalhou-se, num primeiro momento, com dados das estações meteorológicas dos municípios lindeiros, obtidos através do banco de dados do IAPAR e do SIMEPAR, compreendendo o segmento temporal de 1983 a 2004 (este segmento foi adotado visto ser toda a série histórica existente na área); a metodologia proposta baseia-se, primeiramente, na comparação dos dados, estatisticamente, entre estações que se localizam próximas e distantes do lago, para a verificação da variabilidade ou não dos parâmetros analisados, conforme proposto e testado por GRIMM (1986), a qual obteve resultados satisfatórios para tal procedimento; após esta comparação analisam-se dados do satélite NOAA sobre os parâmetros climáticos da região. Num segundo momento, a partir dos dados meteorológicos analisados, são elaborados questionários, aplicados em entrevistas abertas com pessoas residentes na região em torno de 30 anos, tanto no meio rural quanto urbano, conforme metodologia proposta por SARTORI (2000), visando compreensão da percepção climática da sucessão dos tipos de tempo bem como em relação à presença do lago e suas influências no clima local por parte... / The objective of this work is to characterize the local weather of Parana's west region making a comparison between it and the Hydroelectric Itaipu's artificial lake presence created in 1982, as well the climatic perception of the inhabitants of the region in relation to the presence of the lake and its influence into the local weather. This becomes important considering that generally the local weather is strongly influenced by anthropic actions, there have been a caching of 29 billions cubic meters of water in the Itaipu's reservoir, flooding a total area of 1,350 km2, reaching 15 cities in the west of Parana and one in Mato Grosso do Sul, making a great alteration in the landscape.To achieve the referred objective meteorological stations data from the surrounding cities have been used, obtained from IAPAR and SIMEPAR databases, comprehending the period from 1983 to 2004(this period have been adopted because it is all the existent historical serial in the area). The methodology suggested works primary comparing the data statistically, between near to the lake stations and distant ones, to verify the variability or not of the analyzed parameters, as stated and suggested by GRIMM(1986), witch have acquired satisfactory results in such procedure; after this comparison data from the NOAA satellite about the climatic parameters of the region are analyzed. In a second moment, considering the analyzed meteorological data, surveys are made with people who have lived in the region by 30 years, both in the country side as the urban area, according to the methodology suggested by SARTORI (2000), heading to the comprehension of the climatic perception of the succession of weather types as well in relation to the presence of the lake and its influences in the local weather by the people who experiment this fact. In the analyses of the data it was not found a relation between... (Complete abstract click electronic access below)

Alteration of ultramafic rocks is ubiquitous to their occurrence near the surface. Primary mantle minerals like olivine and pyroxenes are unstable at low pressure and temperatures and undergo hydration (serpentinization), carbonation and weathering reactions forming hydrated and carbonated minerals. Employing a variety of analytical techniques including: electron microprobe, X-Ray diffraction, major and trace element geochemistry, Mg isotopes geochemistry and geochemical modelling this work seeks to contrain conditions ofa lteration and trace changes in composition of peridotite during alteration. In Wadi Fins in the southeast of Oman peridotites outcrop at the bottom of a canyon overlaid by a thick sequence 1.5 km of Cretaceous to Eocene shallow oceanic limestones and dolostones. The peridotites exhibit different types of alteration. While the common view is that serpentinization and carbonation of peridotites is isochemical this is not the case for alteration in Wadi Fins. Peridotites tens of meters below the unconformity are characterized by a striking grid of carbonate and serpentine veins. The calcite veins and relatively low MgO/SiO2 suggest that the peridotites reacted with a hydrous fluid derived from interaction of seawater with the overlying sediments composed of limestones with minor amounts of chert. This is further affirmed by average δ13C, δ18O and 87Sr/86Sr from carbonate veins in the peridotites that are similar to values of the sediments. Clumped isotope thermometry on calcite veins in peridotite establish that they formed at 25–60 ℃. Reaction path modeling of carbonate- quartz derived fluids with peridotite reproduces the observed mineral assemblage composed of carbonate and serpentine with similar Mg and MgO/SiO2 at high water to rock ratios, with carbon, H2O and silica added to the rock by the reacting fluid. Close to the unconformity the altered peridotites are characterized by concentric alteration halos recording variable fO2 and fS2. The partially serpentinized cores preserved primary minerals and record extremely low oxygen fugacities (fO2~10^(-75) bars). Two alteration zones are present evident from the alteration color. These zones exhibit nonisochemical alteration characterized by intergrowths of stevensite/lizardite. The alteration zones record progressively higher (fO2) recorded by Ni-rich sulfides and iron oxides/hydroxides. The alteration zones lost 20-30% of their initial magnesium content, together with mobilization of iron over short distances from inner green zones into outer red zones, where iron was reprecipitated in goethite intermixed with silicates due to higher fO2. The loss of magnesium in this peridotites motivated the final section of work. Mg isotopic compositions of partially serpentinized harzburgites and dunites in Oman are identical to average mantle and bulk silicate Earth (δ26Mg=-0.25‰) while altered periodites from Wadi Fins get heavier with increasing alteration. Analyses of peridotite alteration products including samples from Wadi Fins and carbonates from Wadi Tayin were used to show that isochemical serpentinization at low W/R does not fractionate Mg isotopes. I propose a mechanism that with increasing W/R and co-precipitation of Mg-carbonates and serpentine leads to carbonates with light isotopic compositions (Magnesite δ26Mg =-3.3 and dolomite δ26Mg=-1.91) and serpentine with heavy compositions (up to δ26Mg =-0.96 in serpentine veins). This complementary enrichment-depletion and the finite 14C ages of the carbonates suggest that serpentinization is ongoing along carbonation in Oman at ambient temperatures. Rates of calcite precipitation in travertines inferred from Δ26Mgcal-fl suggest that travertine formation in Oman sequesters a total of 10^6-10^7 kg CO2/yr.