History of the fluids associated with the lode-gold deposits, and complex U-PGE-Au vein-type deposits, Goldfields Peninsula, Northern Saskatchewan, Canada

The varied mineral deposit types of the Beaverlodge area, Northern Saskatchewan, indicate that the rocks have undergone a complex and protracted fluid history. All of the deposits studied are physically hosted in a variably metamorphosed sedimentary sequence, the Aphebian-aged Murmac Bay Group (complex Au-PGE-U vein-type deposits, e.g. Nicholson, Fish Hook), or within granites "intrusive" into the Group (lode-­gold deposits, e.g. Box, Athona, Frontier). The complex Au-PGE-U vein-type deposits, and other minor mineralizations, are genetically associated with later, overlying sedimentary sequences such as the Late Aphebian to Helikian-aged Martin and Athabasca Groups. The succession of sedimentary basins was probably controlled by the virtually continuous tectonic evolution of the area prior to, and during, the Thelon-Talston (ca. 2.0 Ga), and Hudsonian (ca. 1.8 Ga) orogenies. The first fluid event identified is F1, which occurred at ca. 1.97 to 1.95 Ga, when the mine granites were formed as nearly in-situ melts in the presence of a "metasomatic" fluid. The origin of the event is attributed to the burial of the Murmac Bay Group, presumably in a subduction-related setting, during the Thelon-Talston orogeny at ca. 2.0 to 1.9 Ga. δ¹⁸O values of the granite minerals indicate an isotopic closure temperature for this event of 550 to 650°C, and that the "metasomatic" fluids may have been related to magmatic activity that occurred at deeper structural levels in the subduction zone. The development of a regional foliation, D1, may have occurred during the earlier stages of this event as well. The Thluicho Lake Group may be the remnants of a turbidite basin that developed in the back-arc area of the subduction zone. The next fluid event documented is that which produced lode-gold quartz vein mineralization, associated with D2 deformation. This event is recorded in the veins by Type I and Ia fluid inclusions, and by the stable isotopic compositions of vein minerals as fluid events F2 and F3 (Which are likely parts of the same overall fluid event). This fluid, at least during the late stage of vein development, is suspected to have been associated with gold deposition, and is indicated to have had minimum temperatures of about 300°C, and minimum pressures of 2.5 to 3.0 kbars. As the fluid was C0₂-bearing, and the inclusion populations appear to indicate pre-­entrapment immiscibility, these temperatures and pressures are trapping conditions. This is confirmed by some stable isotopic fractionations between quartz and chlorite gangue minerals that yield temperatures of 300 to 400°C. The minerals were in equilibrium with a fluid of metamorphic origin. Rb/Sr ages of vein minerals indicate they are at least 1.84 Ga, and probably between 1.855 and 1.84 Ga, suggesting that the D2 folding, and the retrograde metamorphic fluid that likely caused the lode-gold mineralization, were related to uplift during early Hudsonian collision. The source of the retrograde fluids is not clear, but the fluids may have been derived from the dehydration of material that was subducted during the Thelon-Talston orogeny, as the high ⁸⁷Sr/⁸⁶Sr ratios of the vein minerals, as well as feldspar from the Mine granites, imply that F1 to F3 fluids were derived from, or interacted with significantly older (i.e. deeply buried) crustal material. The fluid represented by Type II inclusions is of an uncertain origin, but clearly post-dated the lode-gold veins (1.84 Ga), and pre-dated the Au-PGE-U mineralization (ca. 1.75 Ga?). This fluid event appears to have been regionally extensive, however, and may be related to events in the Beaverlodge area that are thought to have occurred ca. 1.78 to 1.74 Ga, such as regional albitization, or the simple vein-­type uranium deposits. This age of approximately 1.75 Ga is often referred to as the "late overprint", suggested to be related to the later stages of the Hudsonian Orogen. The "late overprint" is also recorded by feldspars from the Box mine granite, which yield an Rb/Sr age of ca. 1.77 Ga. The Martin basin may have started to form at this time, due to epeirogenic fault movement during the waning stages of the Hudsonian Orogen, and this fluid event may also be related to early diagenesis within the basin. The next fluid event, F4, is recorded by primary fluid inclusions in the complex AU-PGE-U vein-type deposits, which contain fluids of a moderately high salinity (28 to 36 wt % NaCl eq.). A similar fluid is found in secondary Type IV inclusions from the lode-gold veins, and in fluid inclusions from the "sponge rock" zones that have locally altered the mine granites. Stable isotopic equilibration temperatures of vein minerals from the Nicholson and Quartzite Ridge deposits indicate that the fluid was at a temperature of 100 to 120°C. The age of this fluid event may be as old as ca. 1.8 to 1.7 Ga, because the depleted δD value of the fluid, at approximately -90 permil, implies a high latitude for the area. The area was only located at the required high latitudes during two periods of time. For this reason, it is possible that Au-PGE mineralization, such as the Nicholson and Quartzite Ridge deposits, may have formed from diagenetic basinal fluids derived from, or influenced by, the Martin basin, or an unrecognized "proto-Athabasca" basin. Whether or not uranium accompanied the gold and platinoids, or was later overprinted on pre-existing Au-PGE mineralization is not presently known. F5 is the youngest fluid event, recorded by the late U­-bearing comb veins. The fluids were of a high salinity (40 wt. % NaCl eq.) , and stable isotopic equilibrium fractionations between vein minerals indicate a temperature of approximately 175°C. The calculated stable isotopic values of the fluid are similar to those of the diagenetic fluids in the Athabasca basin between ca. 1.6 and 1.0 Ga, during which time the unconformity-type and complex vein-type uranium deposits were formed. As mentioned above, this may be the time during which uranium mineralization overprinted the AU-PGE mineralization, forming "hybrid" complex Au-PGE-U vein-type deposits. An early stage of the F5 fluid event is represented by Type III secondary inclusions in the lode-gold veins. The moderate salinity of the fluid (10 to 15 wt. % NaCl eq.) is similar to fluid inclusions observed in quartz overgrowths from the Athabasca basin, where the fluid is interpreted to be of an early diagenetic origin

Incorporating seascape ecology into the design and assessment of marine protected areas

Seascape ecology is an emerging sub-discipline of marine ecology, which examines the effect of spatial heterogeneity in marine ecosystems on ecological processes and species distributions. The opportunity to study seascape ecology in many coastal regions has been greatly assisted by advances in remote sensing technologies, which can acquire detailed habitat data over a range of spatial scales. This now allows quantification of spatial patterns in seascapes and the scientific examination of the ecological consequences of such patterns. Current research applying this approach has begun to demonstrate the importance of seascape connectivity and structural complexity in driving spatial variability of marine fish assemblages. Much of this research however, has focussed on tropical regions and as a result the effect of seascape patterning on temperate fishes remains poorly resolved. The aim of this thesis was to examine the seascape ecology of temperate fishes in two Marine Protected Areas (MPAs) in south-east Australian waters and also examine how this approach can aid in the design and assessment of MPAs. I achieved this by investigating spatial variability in temperate fish assemblages over three scales to examine the effect of i) three-dimensional reef structural complexity, ii) differences among habitat types (seagrass, rocky reef and unvegetated sediment) and iii) the seascape connectivity of habitats. I used baited remote underwater video systems (BRUVs) to survey demersal and mid-water fish assemblages in conjunction with existing habitat mapping to examine the relationship between fish and their habitats. In the Lord Howe Island Marine Park (LHIMP), reef structural complexity strongly influenced the abundance of yellowtail kingfish; Seriola lalandi. Despite being heavily targeted by fishers, a ‘conventional’ (GLM) assessment on the LHIMP revealed no difference in the abundance of S. lalandi between fished and unfished zones. However, on accounting for reef structural complexity in the assessment, I revealed substantially higher abundances of S. lalandi in unfished zones. This positive effect was only observed in their optimal habitat, reefs of high structural complexity. In the Jervis Bay Marine Park (JBMP), habitat type (seagrass, rocky reef and unvegetated sediment) was a strong and consistent predictor of the demersal fish assemblage but did not influence fishes in the mid-water environment. Although habitat influenced the abundance of many demersal fishes, some taxa from the demersal assemblage displayed no affinity to underlying habitat type. Seascape composition and connectivity also appeared to strongly influence temperate fish assemblages. The abundance and diversity of temperate fishes was correlated with the area of rocky reef and seagrass within the surrounding seascape. The apparent importance of seascape connectivity was also noted in the LHIMP, where adult black rockcod (Epinephelus daemelii) were only recorded in areas adjacent to their nursery grounds. Finally, I sought to compare the effectiveness of attractants other than bait (sight and sound stimuli) to entice pelagic fishes to video systems positioned in the mid-water environment. I found the combination of sight, sound and scent attractants on mid-water remote underwater videos (RUVs) recorded a substantially higher abundance and shorter time of first arrival of pelagic fishes compared to RUVs with one or no attractant. I suggest future studies using this sampling method to survey pelagic fishes employ multiple attractants. My findings demonstrate that temperate fishes are influenced by patterns in seascapes and habitats at a number of spatial scales. They also have important implications for spatial conservation strategies such as MPAs, particularly in terms of their design, assessment and adaptive management. Representation of seascape variability over a number of spatial scales in MPA planning is likely to better represent temperate fish assemblages. Furthermore, I demonstrate that habitat classes and measures of structural complexity are appropriate surrogates for certain fishes, which is useful in MPA planning. Finally, I demonstrate that accounting for seascape variability in MPA evaluation is likely to provide a better assessment and clearer understanding of ecological change associated with this management action. In conclusion, integrating seascape ecology into MPA science will increase the usefulness of this conservation strategy to combat growing declines in global marine biodiversity

A Survey of digital and offset print quality issues

Using an Internet-based industry survey, the differences and similarities of offset and digital print demerits within the print industry are examined. Running parallel to this examination is a look at the extent to which demerit-based quality assurance procedures exist within the printing industry. The survey findings indicate that offset and digital printing processes share common color-related print demerits. What differentiates offset print demerits from digital print demerits can be attributed to two factors: (1) technology differences and (2) printing standards. Offset printing, given the multitude of material choices, produces more frequent print demerits, relating to non-conforming materials. Digital print demerits more likely result from technical constraints such as addressability and resolution. The other factor associated is a lack of printing standards for digital printers. While both processes show a high frequency of color-related problems, offset print providers have more tools and standards available for addressing these problems. Digital print providers, on the other hand, have few color standards or tools for solving similar problems. When examining procedures for defect prevention, the general lack of digital printing standards makes the use of formal quality assurance procedures difficult. Offset print providers are more likely to have formal quality assurance procedures for dealing with frequent and severe print demerits and formal procedures for how customer quality requirements are communicated

Voltammetry at Hexamethyl-P-Terphenyl Poly(Benzimidazolium) (HMT-PMBI)-Coated Glassy Carbon Electrodes: Charge Transport Properties and Detection of Uric and Ascorbic Acid

We describe the voltammetric behavior of an anion-exchange membrane, hexamethyl-p-terphenyl poly(benzimidazolium) (HMT-PMBI). The anion-exchange properties of HMT-PMBI chemically modified electrodes were investigated using K4Fe(CN)6 and K2IrCl6 as redox probes. The permselectivity properties of HMT-PMBI chemically modified electrodes were ascertained using tris(2-2’)bipyridyl-ruthenium(II) chloride Ru(bpy)32+. Cyclic voltammetry and chronoamperometry were utilized to extract parameters such as the concentration of the redox mediators inside the films and the apparent diffusion coefficients. We found the concentration of K4Fe(CN)6 and K2IrCl6 redox species within HMT-PMBI-coated films to be on the order of 0.04–0.1 mol·dm−3, and values of Dapp ca. 10−10–10−9 cm2·s−1. To evaluate the possibility of using such a polymer coating in electroanalysis, HMT-PMBI-modified electrodes were utilized for the voltammetric detection of uric acid in artificial urine, Surine® and ascorbic acid in Vitamin C samples. The results showed that HMT-PMBI-coated electrodes can detect uric acid in Surine® with a limit of detection (LoD) of 7.7 µM, sensitivity of 0.14 µA·µM−1·cm−2, and linear range between 5 μM and 200 μM, whereas for Vitamin C tablets, the LoD is 41.4 µM, the sensitivity is 0.08 µA·µM−1·cm−2, and the linear range is between 25 μM and 450 μM

An organocatalytic asymmetric approach to chiral proline derived diketopiperazines related to the prenylated indole alkaloid family

The prenylated indole alkaloids are a large family of natural products that have been isolated from various marine and terrestrial strains of Penicillium, Aspergillus and Malbranchea fungi. These compounds possess complex polycyclic structures including a characteristic bicyclo[2.2.2]diazaoctane core and have displayed wide-ranging biological activities. Chapter 1 gives an introduction to the prenylated indole alkaloids and important synthetic strategies to the key bicyclic core and an overview of previous work from our research group in this area. Recent work showed that triketopiperazines will undergo highly enantioselective Michael-additions and Michael addition–ring-closure reactions, efficiently generating compounds possessing the bicyclo[2.2.2]diazaoctane core found in the natural products. Chapter 2 discusses the extension of previous methodology towards a bicyclic triketopiperazine derived from proline including its synthesis and successful implementation in asymmetric Michael additions. Chapter 3 then explores the Michael addition–ring-closure of the proline derived triketopiperazine which was found to give highly enantioselective and high yielding access to hydroxy diketopiperazines possessing the key bicyclo[2.2.2]diazaoctane. The chapter also contains further transformations towards the natural product scaffold including a radical Barton-McCombie deoxygenation. Chapter 4 focusses on a novel Michael–Michael cascade strategy for the synthesis of molecules possessing the bicyclo[2.2.2]diazaoctane core of the prenylated indole alkaloids

Expanding Space: the Root of all Evil?

While it remains the staple of virtually all cosmological teaching, the concept of expanding space in explaining the increasing separation of galaxies has recently come under fire as a dangerous idea whose application leads to the development of confusion and the establishment of misconceptions. In this paper, we develop a notion of expanding space that is completely valid as a framework for the description of the evolution of the universe and whose application allows an intuitive understanding of the influence of universal expansion. We also demonstrate how arguments against the concept in general have failed thus far, as they imbue expanding space with physical properties not consistent with the expectations of general relativity.Comment: 8 pages, accepted for publication in PAS

TeV Gamma Rays from Geminga and the Origin of the GeV Positron Excess

The Geminga pulsar has long been one of the most intriguing MeV-GeV gamma-ray point sources. We examine the implications of the recent Milagro detection of extended, multi-TeV gamma-ray emission from Geminga, finding that this reveals the existence of an ancient, powerful cosmic-ray accelerator that can plausibly account for the multi-GeV positron excess that has evaded explanation. We explore a number of testable predictions for gamma-ray and electron/positron experiments (up to ~100 TeV) that can confirm the first "direct" detection of a cosmic-ray source.Comment: 4 pages and 3 figures; Minor revisions, accepted for publication in Physical Review Letter

“Pro-life” in the Czech Republic – What Kind of Europeanization Is Present?

This paper attempts to show what effects Europeanization has had on the pro-life movement in the Czech Republic. The first section of the text outlines a multifaceted concept of institutional theory based on historical institutionalist ideas. Next, it looks at one specific institutional process, Europeanization, informed by the work of Radaelli as well as della Porta’s and Caiani’s work on mobilization in the European Union. The following section defines the relevant actors in the Czech pro-life movement. Finally, the paper applies this concept of Europeanization of social movements to the Czech pro-life case. The paper concludes with observations that Europeanization of the Czech pro-life movement is uneven, manifesting itself among some actors, though not all, and in some areas of Europeanization. Charitable organizations as well as one highly visible activist group are highly associated with processes of Europeanization; on the other hand, in most cases, other activist groups in the pro-life movement in the Czech Republic are more highly influenced by more general trends in interest-group internationalization. These insights may pave the way for additional research on trends both of the European pro-life movement as a whole, as well as serving as a touchstone for improving such theoretical concepts as “Europeanization” vis-à-vis “globalization” or “European integration”.This paper attempts to show what effects Europeanization has had on the pro-life movement in the Czech Republic. The first section of the text outlines a multifaceted concept of institutional theory based on historical institutionalist ideas. Next, it looks at one specific institutional process, Europeanization, informed by the work of Radaelli as well as della Porta’s and Caiani’s work on mobilization in the European Union. The following section defines the relevant actors in the Czech pro-life movement. Finally, the paper applies this concept of Europeanization of social movements to the Czech pro-life case. The paper concludes with observations that Europeanization of the Czech pro-life movement is uneven, manifesting itself among some actors, though not all, and in some areas of Europeanization. Charitable organizations as well as one highly visible activist group are highly associated with processes of Europeanization; on the other hand, in most cases, other activist groups in the pro-life movement in the Czech Republic are more highly influenced by more general trends in interest-group internationalization. These insights may pave the way for additional research on trends both of the European pro-life movement as a whole, as well as serving as a touchstone for improving such theoretical concepts as “Europeanization” vis-à-vis “globalization” or “European integration”