Ore-forming processes are relatively well understood on Earth, but little is known about mineralization processes on Mars. By applying terrestrial analogs, using data collected from orbital and rover missions and evidence for hydrothermal activity from alteration assemblages, the types and locations of different ore-forming processes have been investigated with the aim of discovering concentrations of mineral resources on Mars. These resources are likely to be of critical importance for future manned missions to Mars, and insight gained towards mineralization on Mars may also advance our understanding of terrestrial deposits.

The Lac St. Jean area in the Grenville Province of Quebec contains abundant anorthosite-hosted Fe-Ti-V and Fe-Ti-P mineralization comprised of massive to semi-massive Fe-oxides (magnetite ± ilmenite ± Al-spinel) and nelsonite (~2/3 oxide, ~1/3 apatite), respectively. Currently, information regarding regional-scale variation of mineralization, with respect to the composition of Fe-oxides, their relationship with host rocks, and genesis of the mineralization (i.e. immiscibility of a Fe-Ti ± P-rich magma vs. fractional crystallization) are not well constrained. In order to gain information into these enigmatic deposits, modern techniques involving in-situ laser ablation (LA)-ICP-MS analysis of Fe-oxides and apatite at the University of Ottawa combined with detailed petrography and whole rock lithogeochemistry were applied to samples from mineralization and host anorthosites from 2 Fe-Ti-V and 4 Fe-Ti-P deposits/occurrences. Results show that magnetite from Fe-Ti-P mineralization has a more evolved composition relative to magnetite from Fe-Ti-V mineralization. However, observed differences in; 1) relative abundance of Fe-oxide phases, 2) Fe-oxide exsolution textures, 3) visible corona-forming reactions with co-existing silicate phases (when present), and 4) whole rock compositions of corresponding massive oxide samples indicate possible post cumulus changes on primary composition of magnetite within each deposit/occurrence in this study. Post-cumulus processes appear to have a limited effect on the primary magmatic composition of apatite. Therefore, apatite appeared to be a robust indicator of primary magmatic compositions and was used to describe differences regarding the compositions of parental magma and oxygen fugacity (fO₂) conditions among the Fe-Ti-P deposits/occurrences. This study shows that, when combined with detailed petrography and whole rock lithogeochemistry, in-situ trace element composition of Fe-oxide minerals and apatite is a reliable indicator of the physiochemical conditions of the magmas which formed Fe-Ti-V and Fe-Ti-P mineralization within the Lac St. Jean area.

Unconformity-related uranium deposits in the Athabasca Basin represent a significant global resource of uranium. One such deposit, the Phoenix Deposit, discovered in 2007 on Denison Mine’s Wheeler River property, shares similarities with other deposits in the Basin. The Phoenix Deposit is located at the apex between a basement shear structure, and the unconformity between the crystalline basement and overlying sandstones. The shear structure extends into the sandstones, this structure controls the distribution of alteration minerals in the basement and early alteration phases in sandstones. The shear structure extending to sandstones is not spatially associated with late alteration phases associated with the uranium deposit, suggesting that the structure was not important for uranium mineralisation. Bulk rock compositions of sandstones show chimney-like distribution of elements above the uranium deposit. The most notable ones are the distribution of yttrium, and boron. Rare earth elements and yttrium are not soluble in aqueous fluids at low temperatures and they are enriched in uranium ore. Therefore, the chimney-like distribution of elements are attributed to uraniferous hydrothermal activity in sandstones. Petrographic and chemical analysis of alteration associated with the Phoenix Deposit shows two types of tourmaline, a pre-ore (Tur 1) in the basement, which is likely a metamorphic product (Tur1) and a syn-ore magnesiofoitite (Tur 2) in the basement and the sandstones. Three generations of chlorite are identified within the alteration halo of the Phoenix Deposit; an early Fe-rich clinochlore (C1) in the basement and sandstones, the second generation, Mg-rich sudoitic chlorite (C2) in the basement, and a late, sudoitic chlorite (C3) in the basement and sandstones. Illite shows three types; an early and late M1 and a late M2. M1 is found as two polytypes, 1Mc and 1Mt, in the basement and sandstones, with the 1Mt having a spatial relationship with the uranium deposit. Late M2 illite is coarse-grained and occurs in the basement and sandstones. Near Infrared (NIR) spectra of sandstones overlying the deposit shows absorption features between 600 and 700 nm. It is considered that these absorption features appear to have been produced during late hydrothermal activity and may have a temporal as well as spatial relationship with uranium mineralisation.

The Pierina high-sulphidation epithermal Au-Ag deposit is located in the Cordillera Negra of north-central Perú, ~ 5km north of the coeval intermediate-sulphidation Ag–base metal Santo Toribio deposit, and in rocks of the Calipuy Supergroup. The deposit contains ~ 8 M oz Au, hosted in non-refractory iron oxides and, with heap-leach extraction, is one of the lowest-cost Au producers in the world. Stage Ia (15 Ma) and Ib (14.4 Ma) advanced-argillic alteration formed from mixed magmatic and meteoric waters. The main, 14.4 Ma event produced vuggy quartz alteration, focussed in a 16.9 Ma dacitic pumice-lithic tuff, and surrounded by quartz-alunite, quartz-dickite, and illite-montmorillonite alteration zones, the product of increased meteoric water contributions towards the periphery of the deposit. Stage II sulphide-barite mineralization introduced gold and silver, hosted submicroscopically in the disseminated high-sulphidation pyrite-enargite assemblage. Precipitation occurred from a low-to-medium - salinity magmatic fluid that mixed with meteoric waters at the site of ore deposition. A 14.1 Ma 40Ar/39Ar age for supergene alunite records the rapid incursion of meteoric waters into the deposit. The resulting oxidation of sulphides to schwertmannite, goethite, and hematite was facilitated by microbes, recorded by the stable-isotopic compositions of supergene barite+acanthite. Schwertmannite is enriched in Au and Ag and is the main precious-metal host. Regional pedimentation is inferred to have initiated retrograde boiling of the source magma chamber at 15 Ma, with renewed magma incursion triggering major alteration at 14.4 Ma. Both events involved the exsolution of an SO2-rich vapour and a more saline aqueous fluid. The latter migrated to Santo Toribio generating phyllic alteration and intermediate-sulphidation mineralization, whereas the SO2-rich vapours caused pyrite-bearing feldspar-destructive alteration along fluid pathways during ascent to Pierina. The subsequent single-phase, H2S-rich mineralizing fluid exsolved from the retracting magma at higher pressures. Vapour contraction during ascent along altered, unreactive pathways minimized the loss of S- and H+, optimizing the transport of Au as AuHS0. Watertable displacement resulting from pediment incision promoted the flow of groundwater into the epithermal environment where mixing with magmatic fluids precipitated gold. Supergene oxidation optimized conditions for microbial activity, a critical factor in the generation of economic mineralization. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2009-04-01 16:02:47.525

M.Sc. / The potential target areas for coalbed methane in South Africa are reviewed and a case study based on borehole data from the north-eastern Karoo basin was undertaken. The Early Permian coal seams of the Karoo Supergroup occur in several discrete sedimentary basins in South Africa, of which the Karoo basin is the largest. Using screening criteria based on geological, petrographical and analytical data some of the coal deposits can be excluded as potential coalbed methane producers. These include the Molteno Coalfield, large parts of the Karoo basin coal deposits and some of the Northern Province's coal deposits which are structurally disturbed. The traditional mining areas in the Free State, Witbank and Highveld coalfields are excluded from the coalbed methane study because the target seams occur at less than 200 metres below surface, too shallow for gas retention. Some of the coal seams in the Waterberg Coalfield occur at depths of several hundred metres below surface and these are unlikely to be mined by conventional means. These deep coals may be ideal coalbed methane producers. This regional overview was based on available, published data and two important parameters, permeability of coal and coalbed hydrology are unknown but important factors that will need to be taken into account in any future evaluations. The case study focused on an area close to Amersfoort that has a predicted potential for coalbed methane production. The study utilized 465 borehole descriptions from which isopach maps and geological cross-sections were constructed. Limited samples of borehole core provided lithological information from which a facies analyses was undertaken so as to establish the hydrodynamic origin of each facies types. The main lithofacies associated with the coal seams are mudstones, carbonaceous shales and fine- to coarse-grained sandstone. These data were combined with analyses from limited permeability data, petrographical data and proximate analyses for the Gus and Alfred seams. In addition to the sedimentary rocks, the role of dolerite intrusions was found to be significant as these occur as thick sills and dykes that occur below, within and above the coal seams. These may compartmentalize the seams into secondary targets within the study area. Thick sills overlying the coal zone also increase static loading and may be advantageous with respect to reducing the minimum depthbelow- surface requirements. Potential coalbed methane target areas are identified, although the entire study area is not suitable due to structural displacement of the coal seams, thinning of coal in places and devolatization caused by the dolerites.

The P2 reverse fault in the metasedimentary basement rocks of the eastern Athabasca Basin is the main structural control of the world-class McArthur River uranium deposit. The earliest preserved assemblage along the fault is oxy-dravite, rutile, quartz, pyrite and graphite. This assemblage formed at temperatures of up to 890 °C, during regional metamorphism or a thermal event at ~1.75 Ga. The exhumation and surface exposure of the rocks was accompanied by paleo-weathering, and the deposition of the Athabasca sandstones. Diagenetic fluids of the sandstones altered the basement rocks to form Sr-Ca-SO42- rich aluminum phosphate sulfate (APS) minerals + hematite ± kaolin. The onset of hydrothermal activity along the basement and the P2 fault is recorded by local anatase at 1569 ± 31 Ma. Uraniferous fluid formed an assemblage of sudoite illite, magnesio-foitite and LREE+P rich APS minerals (rims earlier diagenetic-type APS minerals) along the entire P2 fault. Magnesio-foitite exhibits a high X-site vacancy (0.70 – 0.85 apfu) and contains high Al in its Y-site (0.70 – 1.12 apfu), suggesting that magnesio-foitite likely replaced kaolin. The REE pattern of magnesio-foitite is similar to that of uraninite (CeN<YN), likely due to their co-crystallization with LREE-rich APS minerals. APS minerals show variably high S/P ratios (0.05 - 0.21) in proximity to the deposit and low ratios (0.11 - 0.13) far from the deposit along the P2 fault, indicating reducing conditions in the ore zone. Low values of δD (-41 to -98 ‰) and high values of δ11B (+13.1 to +23.2 ‰) for magnesio-foitite suggest that groundwater interacted with carbonates or evaporites and was progressively enriched in 11B through interaction with illite and kaolin minerals. This work demonstrates that i) the P2 fault was a site of extensive fluid-rock interaction, ii) mineralizing fluids travelled along the entire P2 fault in the basement, iii) the deposition of the McArthur River deposit was controlled by the availability of a reducing fluid through the P2 fault, and iv) mineral chemistry (tourmaline and APS minerals) may help identify fertile faults in exploration for uranium deposits.

The Neoarchean greenstone belts of the Canadian Superior Province host world-class Au and base metal (Cu-Zn-Pb) massive sulfide deposits with distinct geological features, including a wide range of different host rocks and crustal settings. The range of settings is reflected in the trace metal signatures of their ores. This study examines the trace element geochemistry of pyrite from 55 different Archean volcanogenic massive sulfide (VMS) deposits in Canada to test the relationship to their host rocks, the deposit sizes and their grades. The database includes 258 samples of pyrite from 47 deposits in the Abitibi Greenstone Belt (AGB), together with 30 samples from 8 deposits in the Western Superior (Sturgeon Lake, Uchi, Benny, and Manitouwadge belts) and 45 samples from 6 deposits in the Slave Province (Hackett River, Amooga Booga, and High Lake belts). We used statistical methods to characterize the trace element geochemistry of pyrite in grab samples from the deposits, as well as larger samples representing many thousand of tonnes of ore from monthly concentrates. The study focused on pyrite mineral separates comparing samples from different deposits and different ore types within individual deposits. The analysis shows the trace element geochemistry of pyrite is a useful fingerprint of the different mineralizing systems, with trace element enrichments and depletions reflecting different source rocks, inferred temperatures of ore formation, and the scales of the hydrothermal systems. A comparison of the Abitibi samples to other deposits in the Superior Province shows distinct trace element signatures between primitive and more evolved crustal settings of different age. Similar results are found among 102 samples of pyrite from 30 deposits in Proterozoic and Phanerozoic belts across Canada. District-scale variations in pyrite chemistry mainly reflect host rock and correlate different bulk Cu/(Cu+Zn) grade ratios of the deposits. Pyrite samples from Cu-rich deposits are enriched in Cu, Bi, Co, Ni, Se, Te and Mo; whereas pyrite samples from Zn-rich deposits are enriched in Pb, Ag, Cd, In, Ga, Sn, As, Sb, Hg and Tl. The same patterns are observed in Cu-rich versus Zn-rich zones of individual deposits. Statistical analyses reveal pyrite samples from VMS deposits in the AGB that are associated with primitive mafic-ultramafic tholeiitic rocks (e.g., Potter-Doal and Genex from Timmins, and East Sullivan and Dunraine from Val d'Or camps) are enriched in Cu (>5000 ppm), Co (>1500 ppm), Se (>4000 ppm), and Ni (>250 ppm), whereas pyrite from deposits associated with tholeiitic to calc-alkaline felsic rocks (e.g., Abcourt-Barvue from the Amos-Barraute camp) are commonly enriched in Pb, Ag, Au, Cd, In, Sn, As, Sb, Hg, Tl (10s to 100s of ppm). These variations closely match primary trace element abundances in unaltered volcanic rocks compiled from over 4000 high-quality analyses of samples from the Superior Province. Whole-rock data for rhyolite confirm high concentrations of Pb, Ag, Bi, Te, Cd, In, Ga, Sn, Hg, and Tl compared to basalt and komatiite, which have higher Cu, Co, Ni, and Se. The variation in trace element concentrations in pyrite is remarkably consistent for different deposits. We note that randomly sampled pyrite from almost any part of a deposit with a bulk enrichment in a particular element shows notable enrichment in that element compared to pyrite from other deposits. Pyrite from a deposit with a bulk enrichment in Te, for example (Quemont in the Noranda camp), will almost certainly contain more Te than pyrite from other Te-poor deposits. We test this observation among 47 deposits for 15 different elements. Pyrite samples from Au-rich VMS deposits (e.g., Horne, Quemont, Bousquet #2, and Dumagami) have anomalous Au (>6 ppm) and Te (>70 ppm). Co-enrichment in other elements such as Bi, Se, In and Sn may reflect a common felsic magmatic source. Other trace element enrichments appear to reflect the scale of the hydrothermal system (e.g., depth and extent of leaching). For example, pyrite samples from several large-tonnage deposits (Kidd Creek, Horne #5 Zone, and Geco) have high Sn concentrations (from 450 to 15000 ppm) possibly reflecting the large volumes of felsic rock from which the Sn was extracted. In other deposits, co-enrichment of Sn with Bi (>100 ppm) and In (>10 ppm) suggest a magmatic contribution to the ore fluids Principal Components Analysis (PCA) combined with hierarchal clustering confirms systematic trace element variability in pyrite from deposits with different host rocks and bulk Cu/(Cu+Zn) ratios. However, pyrite from deposits in different terranes seems to record major differences in the crustal compositions of those terranes. For example, pyrite samples from bimodal-felsic deposits show the same trace element signatures (i.e., enrichments in Ag, As, Sb, and Hg) in the AGB and in the Western Superior. In contrast, pyrite samples from deposits in the Slave craton tend to show a distinct enrichment in Pb, U and Th that may be related to the more mature and thicker crust in the Slave compared to the AGB. Other deposit types (magmatic Cu vein deposits, orogenic Au deposits) also show dramatically different pyrite compositions. Pyrite concentrates from magmatic Cu vein deposits in Chibougamau are enriched in Cu, Co, Ni, Te, As, Sb compared to VMS in the AGB, and samples from orogenic Au deposits in Timmins and Val d'Or are enriched in Au and Mo and depleted in Pb, Bi, As, and Sb compared to VMS. These differences highlight the potential application of the trace element signatures of pyrite during exploration for different deposit types in the same region. Trace element signatures of pyrite in grab samples compared favourably to much larger bulk samples from the same deposits (e.g., monthly concentrates and mine tailings) giving some confidence that the much smaller samples can provide a reliable first-order fingerprint of the deposits as a whole. LA-ICP-MS analyses of individual pyrite grains also agreed well with bulk analyses of pyrite over a wide range of trace element concentrations (10s to 100s of ppm).

The contents of this dissertation fall into two broad areas: geology and history of geology. Although apparently unrelated, the two categories in fact parallel one another. The development of geological systems finds a mirror, on a shorter timescale, in the development of the human understanding of geological systems. The present state of a science - like the present state of an earth system - represents the concatenation of many subtle or evident processes and influences operating over time. Moreover, the events of the past condition the state of the present in science as well as in objects of scientific study. Thus, for instance, to understand why we now hold certain interpretations about the formation of sediment-hosted copper deposits, we must study not only the deposits themselves but the historical development and the philosophical concerns that guided and shaped modern thought about them. In this dissertation the geological and historical aspects are presented in sequence rather than juxtaposed. The geological section comes first, with three chapters detailing the formation and development of the Tenke-Fungurume Cu-Co district and the Central African Copperbelt, followed by another taking a broad view of the mineralogical, geochemical, and metallurgical implications of some of the geological features there. Then follows the history of geology: first two chapters on the role of Georgius Agricola in founding modern geology, and one on how it developed through the following centuries in tune with simultaneous developments in other sciences.

No description available.

Widespread base- and precious-metal anomalies, altered porphyry intrusions and oxidized veins occur in a portion of the Sulphur Springs Range, Nevada (adjacent to the Au-producing Carlin Trend). Some of the Eocene-Oligocene intrusions and cogenetic volcanic rocks in the range exhibit evidence of magma mixing and invite comparisons with other mineralized, Eocene mixed magma systems like the Bingham porphyry Cu deposit 300 km farther to the east. The Sulphur Springs igneous suite ranges compositionally through rhyolite, dacite, andesite and basaltic andesite but is less alkaline than the Bingham volcanic suite. However, the alkali content of the Sulphur Springs suite is similar to other Eocene igneous rocks along the Carlin Trend. The unusual geochemical signature of the Bingham igneous suite, enrichment in Cr, Ni, and Ba, is generally not found in the unaltered Sulphur Springs suite, with the exception of a set of altered mafic and intermediate dikes found in the core of the Sulphur Springs Range. The Bingham and Sulphur Springs volcanic suites both show extensive mixing of mafic magma with more silicic magma to create magma with intermediate compositions. The Bingham suite demonstrates mixing mineralogically by the presence of altered olivine and pyroxene in intermediate composition rocks. One of the disequilibrium Sulphur Springs rocks vividly expresses magma mixing as “andesite" - containing plagioclase, biotite, clinopyroxene, orthopyroxene, olivine, and amphibole coexisting with heavily resorbed megacrysts of quartz and K-feldspar. The Sulphur Springs mixed magma also contains abundant late-stage accessory magnetite and resorbed and oxidized garnet. The most likely parental magmas for this rock are a garnet-bearing quartz porphyry and olivine-bearing basaltic andesite which are both present in the range. Questions these data raise include: 1) Was there an unusual tectonic setting during the Eocene of the western United States that promoted both magma mixing and base- and precious-metal mineralization? 2) How vital might mixing processes and mafic magma be in delivering large amounts of S and chalcophile metals from deeper magmas to the shallow crust and eventual ore deposits?