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The microscopic composition of thirteen samples of epidote related to porphyry Cu mineralization was mapped using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) at the Geological Survey of Canada. The objective of this research is to improve the indicator mineral method of mineral exploration in glaciated terrains by utilizing the trace element composition of epidote. Six bedrock samples from porphyry Cu deposits of south-central British Columbia (Gibraltar, Mount Polley and Woodjam), three bedrock samples from the Nicola Group located close (

Oberthürite, Rh3(Ni,Fe)32S32, and torryweiserite, Rh5Ni10S16, are two new platinum-group minerals discovered in a heavy-mineral concentrate from the Marathon deposit, Coldwell Complex, Ontario, Canada. Oberthürite is cubic, space group , with a 10.066(5) Å, V 1019.9(1) Å3, Z = 1. The six strongest lines of the X-ray powder-diffraction pattern [d in Å (I)(hkl)] are: 3.06(100)(311), 2.929(18)(222), 1.9518(39)(115,333), 1.7921(74)(440), 1.3184(15)(137,355) and 1.0312(30)(448). Associated minerals include: vysotskite, Au-Ag alloy, isoferroplatinum, Ge-bearing keithconnite, majakite, coldwellite, ferhodsite-series minerals (cuprorhodsite–ferhodsite), kotulskite, and mertieite-II, and the base-metal sulfides, chalcopyrite, bornite, millerite, and Rh-bearing pentlandite. Grains of oberthürite are up to 100 × 100 μm and the mineral commonly develops in larger composites with coldwellite, isoferroplatinum, zvyagintsevite, Rh-bearing pentlandite, and torryweiserite. The mineral is creamy brown compared to coldwellite and bornite, white when compared to torryweiserite, and gray when compared chalcopyrite and millerite. No streak or microhardness could be measured. The mineral shows no discernible pleochroism, bireflectance, or anisotropy. The reflectance values (%) in air for the standard COM wavelengths are: 36.2 (470 nm), 39.1 (546 nm), 40.5 (589 nm), and 42.3 (650 nm). The calculated density is 5.195 g/cm3, determined using the empirical formula and the unit-cell parameter from the refined crystal structure. The average result (n = 11) using energy-dispersive spectrometry is: Rh 10.22, Ni 38.83, Fe 16.54, Co 4.12, Cu 0.23 S 32.36, total 100.30 wt.%, which corresponds to (Rh2Ni0.67Fe0.33)Σ3.00(Ni19.30Fe9.09Co2.22Rh1.16Cu0.12)∑31.89S32.11, based on 67 apfu and crystallochemical considerations, or ideally, Rh3Ni32S32. The name is for Dr. Thomas Oberthür, a well-known researcher on alluvial platinum-group minerals, notably those found in deposits related to the Great Dyke (Zimbabwe) and the Bushveld complex (Republic of South Africa).Torryweiserite is rhombohedral, space group , with a 7.060(1), c 34.271(7) Å, V 1479.3(1), Z = 3. The six strongest lines of the X-ray powder-diffraction pattern [d in Å (I)(hkl)] are: 3.080(33)(021), 3.029(58)(116,0110), 1.9329(30)(036,1115,1210), 1.7797(100)(220,0216), 1.2512(49)(0416), and 1.0226(35)(060,2416,0232). Associated minerals are the same as for oberthürite. The mineral is slightly bluish compared to oberthürite, gray when compared to chalcopyrite, zvyagintsevite, and keithconnite, and pale creamy brown when compared to bornite and coldwellite. No streak or microhardness could be measured. The mineral shows no discernible pleochroism, bireflectance, or anisotropy. The reflectance values (%) in air for the standard COM wavelengths are: 34.7 (470 nm), 34.4 (546 nm), 33.8 (589 nm), and 33.8 (650 nm). The calculated density is 5.555 g/cm3, determined using the empirical formula and the unit-cell parameters from the refined crystal structure. The average result (n = 10) using wavelength-dispersive spectrometry is: Rh 28.02, Pt 2.56, Ir 1.98, Ru 0.10, Os 0.10, Ni 17.09, Fe 9.76, Cu 7.38, Co 1.77 S 30.97, total 99.73 wt.%, which corresponds to (Rh4.50Pt0.22Ir0.17Ni0.08Ru0.02Os0.01)∑5.00(Ni4.73Fe2.89Cu1.92Co0.50)Σ10.04S15.96, based on 31 apfu and crystallochemical considerations, or ideally Rh5Ni10S16. The name is for Dr. Thorolf (‘Torry') W. Weiser, a well-known researcher on platinum-group minerals, notably those found in deposits related to the Great Dyke (Zimbabwe) and the Bushveld complex (Republic of South Africa).Both minerals have crystal structures similar to those of pentlandite and related minerals: oberthürite has two metal sites that are split relative to that in pentlandite, and torryweiserite has a layered structure, comparable, but distinct, to that developed along [111] in pentlandite. Oberthürite and torryweiserite are thought to develop at ∼ 500 °C under conditions of moderate fS2, through ordering of Rh-Ni-S nanoparticles in precursor Rh-bearing pentlandite during cooling. The paragenetic sequence of the associated Rh-bearing minerals is: Rh-bearing pentlandite → oberthürite → torryweiserite → ferhodsite-series minerals, reflecting a relative increase in Rh concentration with time. The final step, involving the formation of rhodsite-series minerals, was driven via by the oxidation of Fe2+ → Fe3+ and subsequent preferential removal of Fe3+, similar to the process involved in the conversion of pentlandite to violarite. Summary comments are made on the occurrence and distribution of Rh, minerals known to have Rh-dominant chemistries, the potential existence of both Rh3+ and Rh2+, and the crystallochemical factors influencing accommodation of Rh in minerals.

Marathonite, Pd25Ge9, and palladogermanide, Pd2Ge, are two new platinum-group minerals discovered in the Marathon deposit, Coldwell Complex, Ontario, Canada. Marathonite is trigonal, space group P3, with a 7.391(1), c 10.477(2) Å, V 495.6(1) Å3, Z = 1. The six strongest lines of the X-ray powder-diffraction pattern [d in Å (I)(hkl)] are: 2.436(10)(014,104,120,210), 2.374(29)(023,203,121,211), 2.148(100)(114,030), 1.759(10)(025,205,131,311), 1.3605(13)(233,323,036,306), and 1.2395(14)(144,414,330). Associated minerals include: vysotskite, Au-Ag alloy, isoferroplatinum, Ge-bearing keithconnite, majakite, coldwellite, ferhodsite-series minerals (cuprorhodsite-ferhodsite), kotulskite and mertieite-II, the base-metal sulfides, chalcopyrite, bornite, millerite and Rh-bearing pentlandite, oberthürite and torryweiserite, and silicates including a clinoamphibole and a Fe-rich chlorite-group mineral. Rounded, elongated grains of marathonite are up to 33 × 48 μm. Marathonite is white, but pinkish brown compared to palladogermanide and bornite. No streak or microhardness could be measured. The mineral shows no discernible pleochroism, bireflectance, or anisotropy. The reflectance values (%) in air for the standard COM wavelengths are: 40.8 (470 nm), 44.1 (546 nm), 45.3 (589 nm), and 47.4 (650 nm). The calculated density is 10.933 g/cm3, determined using the empirical formula and the unit-cell parameters from the refined crystal structure. The average result (n = 19) using energy-dispersive spectrometry is: Si 0.11, S 0.39, Cu 2.32, Ge 18.46, Pd 77.83, Pt 1.10, total 100.22 wt.%, corresponding to the empirical formula (based on 34 apfu): (Pd23.82Cu1.19Pt0.18)Σ25.19(Ge8.28S0.40Si0.13)∑8.81 and the simplified formula is Pd25Ge9. The name is for the town of Marathon, Ontario, Canada, after which the Marathon deposit (Coldwell complex) is named.Results from electron backscattered diffraction show that palladogermanide is isostructural with synthetic Pd2Ge. Based on this, palladogermanide is considered to be hexagonal, space group , with a 6.712(1), c 3.408(1) Å, V 133.0(1), Z = 3. The seven strongest lines of the X-ray powder-diffraction pattern calculated for the synthetic analogue [d in Å (I)(hkl)] are: 2.392(100)(111), 2.211(58)(201), 2.197(43)(210), 1.937(34)(300), 1.846(16)(211), 1.7037(16)(002), and 1.2418(18)(321). Associated minerals are the same as for marathonite. Palladogermanide occurs as an angular, anhedral grain measuring 29 × 35 μm. It is white, but grayish-white when compared to marathonite, bornite, and chalcopyrite. Compared to zvyagintsevite, palladogermanide is a dull gray. No streak or microhardness could be measured. The mineral shows no discernible pleochroism, bireflectance, or anisotropy. The reflectance values (%) in air for the standard COM wavelengths for Ro and Ro' are: 46.8, 53.4 (470 nm), 49.5, 55.4 (546 nm), 50.1, 55.7 (589 nm), and 51.2, 56.5 (650 nm). The calculated density is 10.74 g/cm3, determined using the empirical formula and the unit-cell parameters from synthetic Pd2Ge. The average result (n = 14) using wavelength-dispersive spectrometry is: Si 0.04, Fe 0.14, Cu 0.06, Ge 25.21, Te 0.30, Pd 73.10, Pt 0.95, Pb 0.08, total 99.88 wt.%, corresponding (based on 3 apfu) to: (Pd1.97Pt0.01Fe0.01)Σ1.99(Ge1.00Te0.01)∑1.01 or ideally, Pd2Ge. The name is for its chemistry and relationship to palladosilicide.The crystal structure of marathonite was solved by single-crystal X-ray diffraction methods (R = 7.55, wR2 = 19.96 %). It is based on two basic modules, one ordered and one disordered, that alternate along [001]. The ordered module, ∼7.6 Å in thickness, is based on a simple Pd4Ge3 unit cross-linked by Pd atoms to form a six-membered trigonal ring that in turn gives rise to a layered module containing fully occupied Pd and Ge sites. This alternates along [001] with a highly disordered module, ∼3 Å in thickness, composed of a number of partially occupied Pd and Ge sites. The combination of sites in the ordered and disordered modules give the stoichiometric formula Pd25Ge9.The observed paragenetic sequence is: bornite → marathonite → palladogermanide. Phase equilibria studies in the Pd-Ge system show Pd25Ge9 (marathonite) to be stable over the range of 550–970 °C and that Pd2Ge (palladogermanide) is stable down to 200 °C. Both minerals are observed in an assemblage of clinoamphibole, a Fe-rich, chlorite-group mineral, and fragmented chalcopyrite, suggesting physical or chemical alteration, possibly both. Palladogermanide is also found associated with a magnetite of near end-member composition, potentially indicating a relative increase in fO2. Both minerals are considered to have developed at temperatures of 500–600 °C, under conditions of low fS2 and fO2, given the requirements needed to fractionate, concentrate, and form minerals with Ge-dominant chemistries.

At the Gibraltar porphyry Cu-Mo deposit in south-central British Columbia, Canada, geochemical and mineralogical anomalies in till around a cluster of mineral occurrences form amoeboid-shaped dispersal patterns controlled by three phases of ice movement. The glacial dispersal patterns defined by elevated concentrations of ore (Cu, Mo) and pathfinder (Ag, Zn) elements and alteration oxides (Al2O3, K2O) in the till matrix (clay and silt plus clay fractions) extend over areas of 6–36 km2 and are centered on the main economic mineralization. Mineralogical dispersal trains were identified by the high abundances of chalcopyrite, pyrite, jarosite, titanite, and epidote, which were derived from the mineralization and its associated oxidation and alteration zones. These mineralogical anomalies in till extend approximately 30 km2 for chalcopyrite, 62 km2 for jarosite, and up to 136 km2 for epidote. Epidote grains in till with a trace element composition of >10 ppm As, >4 ppm Sb, 30 ppm Cu, interpreted to be related to the porphyry Cu mineralization, were detected in till up to 7 km down-ice from the economic mineralization. This study demonstrates that till geochemistry and mineralogy, combined with geochemical analyses of specific minerals such as epidote, are efficient methods for identifying porphyry Cu mineralization in terrains covered by glacial sediments.

Bedrock samples were collected from the Broken Hammer Cu-Ni-PGE-Au deposit and surrounding host lithologies by the Geological Survey of Canada (GSC) to determine which indicator minerals are indicative of this deposit type. The deposit is known for world-class sperrylite crystals that are as large as 15 mm. The bedrock samples were processed using a combination of crushing, tabling, and heavy liquid separation to produce heavy mineral (>3.2 specific gravity) concentrates, which were then visually examined under binocular microscope. Ore minerals recovered from the mineralized samples include sperrylite (up to 2 mm in size), michenerite, tellurobismuthite, kotulskite, and merenskyite, as well as gold and chalcopyrite. GSC open file 8384 reports the results presented for GSC till samples collected around the deposit.

Sixteen kimberlite boulders were collected from three sites on the Munro and Misema River Eskers in the Kirkland Lake kimberlite field and one site on the Sharp Lake esker in the Lake Timiskaming kimberlite field. The boulders were processed for heavy-mineral concentrates from which grains of Mg-ilmenite, chromite, garnet, clinopyroxene and olivine were picked, counted and analyzed by electron microprobe. Based on relative abundances and composition of these mineral phases, the boulders could be assigned to six mineralogically different groups, five for the Kirkland Lake area and one for the Lake Timiskaming area. Their indicator mineral composition and abundances are compared to existing data for known kimberlites in both the Kirkland Lake and Lake Timiskaming areas. Six boulders from the Munro Esker form a compositionally homogeneous group (I) in which the Mg-ilmenite population is very similar to that of the A1 kimberlite, located 7–12 km N (up-ice), directly adjacent to the Munro esker in the Kirkland Lake kimberlite field. U–Pb perovskite ages of three of the group I boulders overlap with that of the A1 kimberlite. Three other boulders recovered from the same localities in the Munro Esker also show some broad similarities in Mg-ilmenite composition and age to the A1 kimberlite. However, they are sufficiently different in mineral abundances and composition from each other and from the A1 kimberlite to assign them to different groups (II–IV). Their sources could be different phases of the same kimberlite or—more likely—three different, hitherto unknown kimberlites up-ice of the sample localities along the Munro Esker in the Kirkland Lake kimberlite field. A single boulder from the Misema River esker, Kirkland Lake, has mineral compositions that do not match any of the known kimberlites from the Kirkland Lake field. This suggests another unknown kimberlite exists in the area up-ice of the Larder Lake pit along the Misema River esker. Six boulders from the Sharp Lake esker, within the Lake Timiskaming field, form a homogeneous group with distinct mineral compositions unmatched by any of the known kimberlites in the Lake Timiskaming field. U–Pb perovskite age determinations on two of these boulders support this notion. These boulders are likely derived from an unknown kimberlite source up-ice from the Seed kimberlite, 4 km NW of the Sharp Lake pit, since indicator minerals with identical compositions to those of the Sharp Lake boulders have been found in till samples collected down-ice from Seed. Based on abundance and composition of indicator minerals, most importantly Mg-ilmenite, and supported by U–Pb age dating of perovskite, we conclude that the sources of 10 of the 16 boulders must be several hitherto unknown kimberlite bodies in the Kirkland Lake and Lake Timiskaming kimberlite fields.

The 65 Ma Chicxulub impact crater formed in the shallow coastal marine shelf of the Yucatn Platform in Mexico. Impacts into water-rich environments provide heat and geological structures that generate and focus sub-seafloor convective hydrothermal systems. Core from the Yaxcopoil-1 (Yax-1) hole, drilled by the Chicxulub Scientific Drilling Project (CSDP), allowed testing for the presence of an impact-induced hydrothermal system by: a) characterizing the secondary alteration of the 100 m-thick impactite sequence; and b) testing for a chemical input into the lower Tertiary sediments that would reflect aquagene hydrothermal plume deposition. Interaction of the Yax-1 impactites with seawater is evident through redeposition of the suevites (unit 1), secondary alteration mineral assemblages, and the subaqueous depositional environment for the lower Tertiary carbonates immediately overlying the impactites. The least-altered silicate melt composition intersected in Yax-1 is that of a calc-alkaline basaltic andesite with 53.4-56 wt% SiO2 (volatile-free). The primary mineralogy consists of fine microlites of diopside, plagioclase (mainly Ab 47), ternary feldspar (Ab 37 to 77), and trace apatite, titanite,and zircon. The overprinting alteration mineral assemblage is characterized by Mg-saponite, Kmontmorillonite, celadonite, K-feldspar, albite, Fe-oxides, and late Ca and Mg carbonates. Mg and K metasomatism resulted from seawater interaction with the suevitic rocks producing smectite-Kfeldspar assemblages in the absence of any mixed layer clay minerals, illite, or chlorite. Rare pyrite, sphalerite, galena, and chalcopyrite occur near the base of the impactites. These secondary alteration minerals formed by low temperature (0-150 °C) oxidation and fixation of alkalis due to the interaction of glass-rich suevite with down-welling seawater in the outer annular trough intersected at Yax-1. The alteration represents a cold, Mg-K-rich seawater recharge zone, possibly recharging higher temperature hydrothermal activity proposed in the central impact basin. Hydrothermal metal input into the Tertiary ocean is shown by elevated Ni, Ag, Au, Bi, and Te concentrations in marcasite and Cd and Ga in sphalerite in the basal 25 m of the Tertiary carbonates in Yax-1. The lower Tertiary trace element signature reflects hydrothermal metal remobilization from a mafic source rock and is indicative of hydrothermal venting of evolved seawater into the Tertiary ocean from an impactgenerated hydrothermal convective system.

The Geological Survey of Canada (GSC) conducted an indicator mineral study around the komatiite-associated Ni-Cu deposits in the northern Thompson Nickel Belt, northern Manitoba, to document the indicator mineral signatures of the Ni-Cu deposits. Samples used in this study include archived till heavy mineral concentrates from 1996, till and bedrock samples collected in 2005 and 2006, and till samples collected in 2007 as part of another GSC study. The Laurentide Ice Sheet flowed across the Thompson Nickel Belt southwestward, and subsequently westward, and striations from both ice-flow events are readily apparent on outcrops along the Belt. Till samples were collected to evaluate glacial dispersal along both ice-flow trends. Till and bedrock samples were processed to recover heavy (specific gravity>3.2) mineral concentrates. Potential indicator minerals picked from heavy mineral concentrates included Cr-diopside, olivine, chromite, spinel, gahnite, rutile, pink corundum, and sapphirine, as well as metallic minerals such as pyrrhotite, pentlandite, chalcopyrite, pyrite, arsenopyrite, gold, and sperrylite. Elevated chromite abundances combined with the presence of Ni-Cu sulphide minerals are strong indicators of potential magmatic Ni-Cu mineralization in till down ice of the Ni-Cu deposits in the Belt. Chalcopyrite and sperrylite are the most useful metallic indicator minerals as they are the most likely to survive glacial transport and postglacial weathering. Elevated Zn content (>2 wt.% ZnO) in chromite is only found in strongly mineralized rocks and is the strongest indicator for mineralization other than the actual ore minerals. The Zn content in chromite from Ni-deposits might be considerabley lower in regions with lower metamorphic grade and thus this feature does not have universal application. The distribution of Cr-diopside, olivine, enstatite, and chromite are similar and are most abundant just east of the Thompson Nickel Belt, at the Thompson deposit and south of the Pipe deposit. Their mafic Cr- or Ni-rich compositions reflect the abundance of ultramafic rocks in the area. Chemical variations in Cr-diopside (higher Cr, Na) and olivine (variable Ni) and the occurrence of high-grade metamorphic minerals, such as corundum, sapphirine, rutile, and spinel, reflect the higher metamorphic grades in certain areas, rather than presence or absence of mineralization. Exploration along the Thompson Nickel Belt and in the surrounding terranes should consider both the older southwest and younger westward ice-flow events when interpreting and following up till indicator mineral results.

Glacial history studies and analysis of heavy mineral separates from glacial sediments (till and eskers) were undertaken in theBoothia mainland area of central Nunavut. Mapping of surficial macroforms and glacial striae has shown a complex, four phase ice-flow history. From oldest to youngest, the ice-flow history entails: Phase 1 to the north, Phase 2 to the northeast, Phase3 to the east, and Phase 4 to the north. Late-stage, localized ice-flows were determined in some areas, especially around the Harrison Uplands. All of the regional ice-flow phases impacted on the final distribution of glacial erratics in till, but with varied influence, wherein Phase 2 to the NE and Phase 4 to the N in the southern part of Boothia mainland were the most significant glacial dispersal events. During Phase 2, glacial transport distances of greater than 100 km were determined for Paleozoic carbonates and Paleoproterozoic members of the Chantrey Group siliciclastic (pelites, orthoquartzites), and at least 20 km for the Paleoproterozoic marble member of the Chantrey Group. Kimberlite indicator minerals (including mantle ilmenite, forsterite, Cr-diopside, eclogitic and peridotitic (G9) garnets, chromite, perovskite and lyndsleyite) and visual gold grains were found in glacial sediments. Prospective zones for kimberlites or gold mineralization are outlined herein from heavy mineral analysis and knowledge of the ice-flow history.

This report presents results of till sampling in the vicinity of the Peddie kimberlite, Bucke Township, in the Lake Timiskaming kimberlite cluster of northeastern Ontario. Thirty till samples were collected (mainly south) of the Peddie kimberlite to document the nature of glacial dispersal from the kimberlite, using both indicator minerals and till geochemistry. Most of the kimberlite indicator minerals in till were found in the finest of the three size fractions (0.25 to 0.5, 0.5 to 1.0 and 1.0 to 2.0 mm) of heavy mineral concentrates examined. Till in the vicinity of the Peddie kimberlite contains a distinctive kimberlitic geochemical signature defined by Ni, Cr, Nb, and Ta, which is most apparent in the coarse to very coarse sand (0.5 to 2.0 mm) and the silt+clay (

The antibiotic virginiamycin was investigated for its effects on growth and lactic acid production by seven strains of lactobacilli during the alcoholic fermentation of wheat mash by yeast. The lowest concentration of virginiamycin tested (0.5 mg Lactrol TMkg−1 mash), was effective against most of the lactic acid bacteria under study, but Lactobacillus plantarum was not significantly inhibited at this concentration. The use of virginiamycin prevented or reduced potential yield losses of up to 11% of the produced ethanol due to the growth and metabolism of lactobacilli. However, when the same concentration of virginiamycin was added to mash not inoculated with yeast, Lactobacillus rhamnosus and L. paracasei grew after an extensive lag of 48 h and L. plantarum grew after a similar lag even in the presence of 2 mg virginiamycin kg−1 mash. Results showed a variation in sensitivity to virginiamycin between the different strains tested and also a possible reduction in effectiveness of virginiamycin over prolonged incubation in wheat mash, especially in the absence of yeast.