Flin Flon Research Articles

Experiences and perspectives of sugar-sweetened beverage consumption among Indigenous adults living in Manitoba

Sugar-sweetened beverages (SSB) are a health policy target. Indigenous populations are among the highest consumers of SSB in Canada. However, the Truth and Reconciliation Commission calls on governments to recognize health disparities among Indigenous populations as a consequence of colonialism and governmental policies. The purpose of this analysis was to explore emergent perspectives of Indigenous adults on experiences and perspectives of SSB consumption. We conducted a community-based participatory study in partnership with three Indigenous-led organizations. From 2019 to 2022, we completed qualitative interviews with Indigenous adults living in Island Lake Anisininew First Nation, Flin Flon, and Winnipeg's North End, a neighbourhood with high concentration of Indigenous people. Interviews were audio-recorded, transcribed verbatim, and analyzed thematically. Seventy-four adults participated in interviews, including 46 women, 26 men, and two identifying as two-spirit. Many participants, across all three locations, repeatedly and consistently described SSB or sugar as an addiction, which formed the primary theme for this analysis: addictive-like consumption of SSB. Addictive-like SSB consumption included comparison to other addictive substances, loss of control, and physical symptoms resulting from SSB intake (both positive and adverse) or attempting to reduce SSB intake. We identified two other secondary themes, i) perceived drivers and contexts of SSB consumption, and ii) health outcomes as a motivator for change. Perceived drivers or contexts included consuming SSB as a means to cope with stress, boredom, and poverty; SSB intake as being intertwined with other addictions or addictive substances; and drinking alone. In conclusion, addictive-like SSB consumption was reported by Indigenous adults. To address SSB intake among Indigenous populations, trauma-informed approaches should be explored that consider the colonial context.

Lateral redox variability in ca. 1.9 Ga marine environments indicated by organic carbon and nitrogen isotope compositions.

The stepwise oxygenation of Earth's surficial environment is thought to have shaped the evolutionary history of life. Microfossil records and molecular clocks suggest eukaryotes appeared during the Paleoproterozoic, perhaps shortly after the Great Oxidation Episode at ca. 2.43 Ga. The mildly oxygenated atmosphere and surface oceans likely contributed to the early evolution of eukaryotes. However, the principal trigger for the eukaryote appearance and a potential factor for their delayed expansion (i.e., intermediate ocean redox conditions until the Neoproterozoic) remain poorly understood, largely owing to a lack of constraints on marine and terrestrial nutrient cycling. Here, we analyzed redox-sensitive element contents and organic carbon and nitrogen isotope compositions of relatively low metamorphic-grade (greenschist facies) black shales preserved in the Flin Flon Belt of central Canada to examine open-marine redox conditions and biological activity around the ca. 1.9 Ga Flin Flon oceanic island arc. The black shale samples were collected from the Reed Lake area in the eastern part of the Flin Flon Belt, and the depositional site was likely distal from the Archean cratons. The black shales have low Al/Ti ratios and are slightly depleted in light rare-earth elements relative to the post-Archean average shale, which is consistent with a limited contribution from felsic igneous rocks in Archean upper continental crust. Redox conditions have likely varied between suboxic and euxinic at the depositional site of the studied section, as suggested by variable U/Al and Mo/Al ratios. Organic carbon and nitrogen isotope compositions of the black shales are approximately -23‰ and +13.7‰, respectively, and these values are systematically higher than those of broadly coeval continental margin deposits (approximately -30‰ for δ13Corg and +5‰ for δ15Nbulk). These elevated values are indicative of high productivity that led to enhanced denitrification (i.e., a high denitrification rate relative to nitrogen influx at the depositional site). Similar geochemical patterns have also been observed in the modern Peruvian oxygen minimum zone where dissolved nitrogen compounds are actively lost from the reservoir via denitrification and anammox, but the large nitrate reservoir of the deep ocean prevents exhaustion of the surface nitrate pool. Nitrogen must have been widely bioavailable in the ca. 1.9 Ga oceans, and its supply to upwelling zones must have supported habitable environments for eukaryotes, even in the middle of oceans around island arcs.

The Effect of Deposited Particulate Matter on the Mobility of Contaminants in the Surficial Soils of Flin Flon, Manitoba, Canada

The Effect of Deposited Particulate Matter on the Mobility of Contaminants in the Surficial Soils of Flin Flon, Manitoba, Canada

Perceptions of Beverages With Non-nutritive Sweeteners Among Indigenous Adults Living in Manitoba and Implications for Type 2 Diabetes

ObjectivesThe purpose of this study was to explore the perspectives of Indigenous adults on consuming beverages with non-nutritive sweeteners. MethodsIn this work, we used a community-based, participatory design in partnership with National Indigenous Diabetes Association, Four Arrows Regional Health Authority, and Fearless R2W. We conducted 74 qualitative interviews with Indigenous adults living in Manitoba, including Island Lake First Nations (n=39), Flin Flon (n=15), and the North End neighbourhood of Winnipeg (n=20). Data were indexed in NVivo, and transcripts were analyzed thematically. ResultsParticipants exclusively discussed beverages with non-nutritive sweeteners (BNNSs) as an alternative to regular pop or sugary drinks, which were widely available, accessible, and consumed. Why or how BNNSs were viewed as an alternative comprised 3 subthemes: an alternative for health reasons; divergent taste preferences; and an alternative with mysterious but negative health effects. Participants who reported regular consumption of BNNSs largely described consuming them to manage type 2 diabetes. Fewer participants discussed BNNS as a means of weight management or as a preventive health behaviour. Participants who did not report regular BNNS consumption described not liking the taste of BNNSs. Finally, many participants described negative health impacts of consuming BNNSs, and specifically aspartame, although few articulated what those negative impacts were. ConclusionsDivergent perspectives among Indigenous adults regarding the health implications of consuming BNNSs may reflect ongoing scholarly debates. These findings have implications for the prevention and dietary management of type 2 diabetes in Indigenous communities.

On the matildite–bohdanowiczite solid-solution series

AbstractA high-grade ore sample from the Cu–Zn–Au Photo Lake volcanogenic massive sulfide deposit (Flin Flon–Snow Lake greenstone belt, Manitoba, Canada) contains a Bi–Ag sulfo-selenide with a composition situated approximately in the middle of the S–Se substitution range (Se ≈ 0.86 apfu and S ≈ 1.05 apfu). These new data, combined with a literature compilation of all publicly available matildite and bohdanowiczite compositional data, reveal a nearly complete range of S–Se substitution between these two minerals, with only the section between BiAgSe0.78S1.18 and BiAgSe0.25S1.75 – about a quarter of the complete S–Se range – not yet documented. These observations suggest that a complete solid-solution series between matildite and bohdanowiczite, as previously suspected, might exist and in a manner similar to the galena–clausthalite complete solid-solution series.

The nitrate-limited freshwater environment of the late Paleoproterozoic Embury Lake Formation, Flin Flon belt, Canada

Earth's atmosphere and surface ocean were pervasively and mildly oxygenated after the ca. 2.4 Ga Great Oxidation Event (GOE), which induced dramatic environmental and biological changes. Positive nitrogen isotopic compositions of Paleoproterozoic marine deposits reveal aerobic nitrogen cycling and the widespread availability of bioavailable nitrate, but the nature of nitrogen cycling in freshwater environment remains unclear. To elucidate the redox conditions and bioavailability of nitrogen, redox-sensitive element and nitrogen isotopic compositions, as well as the depositional age, were determined for black shales of the late Paleoproterozoic Embury Lake Formation, Flin Flon belt, Canada. This formation accumulated in a sulfate-poor freshwater basin isolated from the open ocean, as indicated by its low total‑sulfur/total-organic‑carbon ratio of ∼0.05. Our U-Pb ages for detrital zircons show that the formation is younger than 1862.2 ± 2.6 Ma. Redox-sensitive elements (V and U) in the black shales show positive correlation with detrital tracers Al and Ti. Low enrichment factors for V and U indicate minor authigenic accumulations of the two elements. Moreover, the black shales are depleted in Mn, suggesting deposition under suboxic to anoxic conditions. δ15N values of the black shales are generally < +1‰, indicating a nitrate-limited environment, and are distinct from those of previously reported coeval marine deposits. It is proposed that the nitrate was exhausted by nitrogen-loss processes such as denitrification in the freshwater basin, but was available for nitrate-assimilating organisms in the ocean during the late Paleoproterozoic.

Affinity and Petrogenesis of the Huzyk Creek Metal-Enriched Graphite Deposit: A Metamorphosed Metalliferous Black Shale in the Trans-Hudson Orogen Of Manitoba, Canada

ABSTRACT The Huzyk Creek area is situated along the boundary between the Reindeer Zone and the Superior Boundary Zone of the Paleoproterozoic Trans-Hudson Orogen, where the Precambrian rocks are overlain by Phanerozoic cover. Two drill holes intersect graphite schist that is enriched in V, as well as U, Zn, Mo, and Cu, and is hosted by a metamorphosed wacke-mudstone sequence interleaved with variably altered mafic rocks. Whole-rock lithogeochemistry and Sm-Nd isotope chemistry suggest that the wacke-mudstone package is related to the turbidite-derived Burntwood Group of the Kisseynew Domain and was likely deposited relatively proximal to the Flin Flon arc-collage. A model is proposed in which redox-sensitive metals were leached from rocks of the Flin Flon arc-collage during weathering under oxidizing conditions. The metals were transported in oxygenated surface run-off draining the arc-collage and discharged into the Kisseynew Basin. Shallow waters of the Kisseynew Basin were likely oxygenated and biologically productive; however, the basin was likely euxinic at mid-depths. The mixing of the metal-enriched, oxygenated water with organic matter and euxinic water resulted in the reduction of the redox-sensitive metals and the formation of insoluble organometallic complexes and particles. A highstand, or period of tectonic quiescence, likely halted turbidite deposition and allowed for the settling organic and metal-rich particles to create relatively thick deposits. Burial and metamorphism resulted in the organic-rich material being transformed into graphite, while Mo, Cu, and Zn were partitioned into sulfides. The mineral hosts of V and U are not known at this time. The model calls for the fractionation of redox-sensitive metals from the water column shortly after discharge into the Kisseynew Basin and implies that graphitic horizons in relatively close proximity to the Flin Flon arc-collage have a greater potential for metal enrichment than graphite deposits farther removed from the arc. This model could apply to basins of similar metamorphic grade, age, and tectonic setting around the globe.

Mercury Isotope Variations in Lake Sediment Cores in Response to Direct Mercury Emissions from Non-Ferrous Metal Smelters and Legacy Mercury Remobilization.

Nature archives record atmospheric mercury (Hg) depositions from directly emitted Hg and re-emitted legacy Hg. Tracing the legacy versus newly deposited Hg is still, however, challenging. Here, we measured Hg isotope compositions in three dated sediment cores at different distances from the Flin Flon smelter, the largest Canadian Hg sources to the atmosphere during the 1930s-2000s. During the smelter's operative period, Hg isotope compositions showed limited variations in the near-field lake (<10 km) sediments but were rather variable in middle- (20-75 km) and far-field lake (∼800 km) sediments. Only the post-2000 sediments in middle/far-field lakes showed significantly negative Hg isotope shifts, while sediments from the 1970s-1990s had Hg isotope values resembling those of near-field lake post-1930 sediments. We suggest that the smelter's peak Hg emissions during the 1970s-1990s, which coincided with the deployment of a super stack in the mid-1970s, largely increased the long-range dispersion of smelter plumes. For the top post-2000 sediments, the fugitive dust from ore tailings and terrestrial legacy Hg re-emissions dominated Hg deposition in near-field lakes and middle/far-field lakes, respectively. Our study demonstrates that legacy Hg remobilization now exports substantial amounts of Hg to ecosystems, highlighting the need for aggressive remediation measures of Hg-contaminated sites.

Metal contamination in alkaline Phantom Lake (Flin Flon, Manitoba, Canada) generates strong responses in multiple paleolimnological proxies

The copper-zinc smelter at Flin Flon (Manitoba) operated between 1930 and 2010 and emitted large amounts of metal(loid)s and sulphur dioxide into the atmosphere, damaging the surrounding terrestrial landscapes and depositing airborne industrial pollutants into aquatic ecosystems. However, the extent of biological impairment in regional lakes is largely unknown. Here, we analysed biological and geochemical proxies preserved in a dated sediment core from Phantom Lake, collected seven years after the smelter closed in 2010. Our objectives were to determine how smelting history affected long-term trends in (1) sedimentary elements, (2) biota across multiple trophic levels, and (3) spectrally-inferred chlorophyll a and lake-water total organic carbon. The effects of smelting activities were clearest in the diatom record, in concordance with modest responses in chironomid and cladoceran assemblages. Several metal(loid)s were naturally high and exceeded sediment quality guidelines during the pre-smelting era. With the opening of the smelter, metal(loid) concentrations in sediments increased through the 1930s, peaked in the 1960s, and declined thereafter with technological improvements but remained above background to this day. Although modest declines in inferred lake-water total organic carbon indicate reduced terrestrial carbon supply following sulphate deposition in the catchment, the diatom record showed no evidence of acidification as the lake was and remained well-buffered. Pre-smelting diatom and invertebrate assemblages were diverse and indicated oligo-mesotrophic conditions. Smelting was associated with the loss of metal-sensitive biological indicators and the emergence of assemblages dominated by metal-tolerant, generalist taxa. Diatoms tracked substantial reductions in aerial emissions since the 1990s, particularly after the smelter closed, but also indicated that the biological effects of metal pollution persist in Phantom Lake. Examining the effects of a base metal smelter on a well-buffered lake offered insights into multi-trophic level responses to severe metal contamination and potential recovery without the confounding effects of concurrent changes in lake acidity.

Exploration-resource assessment of productive felsic volcanic centers in the Paleoproterozoic Penokean Volcanic Belt of northern Wisconsin, Michigan and east-central Minnesota, USA

Five productive felsic volcanic centers have been identified in the Paleoproterozoic Penokean Volcanic Belt (PVB). Each center hosts at least one potentially economic polymetallic volcanogenic massive sulfide (VMS) deposit. To date, these drill-defined (inferred + indicated + measured) resources collectively contain over 93 million tonnes of VMS-style, base (Cu, Pb, Zn) and precious metal (Ag, Au) mineralization including nearly 4 million ounces of gold. This does not include smaller, less defined (mostly inferred) deposits in the belt that would increase the total to at least 150 million tonnes. From this resource base only 1.73 million tonnes of actual ore production has occurred. However, previous positive feasibility studies completed on the Crandon (1994), Lynne (1995) and most recently (2020) Back Forty deposits verify a total of approximately 44 million tonnes, or 47% of the total drill-defined resource base, are potentially minable reserves. Currently the PVB resource base remains as unrealized new wealth.Mineral resource assessments completed in 1996 and 2007 collectively suggest there is a high probability of at least 4 to 22 (average ~13) or more VMS deposits remaining to be discovered in the Ladysmith-Rhinelander complex and to a lesser extent the Wausau complex of the PVB. These newly discovered VMS deposits will fill out the tonnage distribution for this belt by following a natural geometric (log normal) progression consistent with established grade-tonnage models. It is postulated that among these will be one giant (>100 million tonnes) deposit. If verified, potentially economic VMS mineralization hosted by the PVB would be comparable to other productive Paleoproterozoic greenstone belts in the Canadian Shield such as Flin Flon (>200 million tonnes) or even approach that of the prolific Neoarchean Abitibi (~775 million tonnes).Exploration to date suggests that many of these undiscovered VMS deposits will be identified in five, highly permissive felsic volcanic centers. These centers, which comprise less than 2% of the known belt, are distributed within the Highway 8 intra-arc rift basin of the 1,880 to 1,860 Ma old Ladysmith Rhinelander volcanic complex. Exact aerial boundaries are poorly defined. However, extrapolation of geophysical, drill hole and rare outcrop data provides a reasonable estimate. Each productive center is stratigraphically associated with major, district-scale, commonly mineralized, meta-argillite formations or formational groups. Felsic centers are identified in the Wausau complex but have thus far been barren of significant VMS-style mineralization as is the adjacent Wausau basin.Future exploration for new VMS deposits should be focused within the productive felsic centers where a number of prospective targets and prospects have been previously identified. Other significant felsic centers likely exist within the Highway 8 basin particularly in Cambrian sandstone-covered areas along the western and eastern margins of the belt. Additionally, at least one felsic center may be present in the Milaca complex which could have VMS potential.Of particular note is the VMS potential of a second mostly Cambrian sandstone-covered, greenstone belt in the Marshfield subterrane (Eau Claire complex). Geophysical data suggest possible back-arc or intra-arc rift basins may be present and historical drilling has identified at least one VMS occurrence. This highly prospective volcanic complex is essentially new hunting ground with its own deposit tonnage distribution of potentially supergene-enriched VMS deposits. Based on criteria set out in a 2007 mineral assessment, this belt has the potential to host at least 1 to a maximum of 15 deposits.

A reinterpretation of the Snow Lake gold camp, Trans-Hudson Orogen, Canada: the use of cleavages as markers to correlate structures across deformed terranes

The Snow Lake gold camp is located within amphibolite facies volcanic rocks of the ca. 1.88–1.87 Ga Flin Flon – Glennie Complex (FFGC) in the Trans-Hudson Orogen, Manitoba. During thrusting and collision with the Archean Sask craton, volcanic rocks were interleaved with turbidites of the ca. 1.855–1.84 Ga Burntwood Group and sandstone and conglomerate of the ca. 1.845–1.835 Ga Missi Group. The main cleavage in the turbidites was previously attributed to thrusting and used as a marker for correlating structures across the camp. A re-examination of this cleavage suggests that it overprints the thrust faults and formed during later collision between the FFGC and the Archean Superior craton. This has important implications as it further suggests that (1) previously unrecognized, early brittle thrust faults repeat volcanic stratigraphy and may have created the boundary conditions that enabled the formation of ductile thrust faults, fold nappes, and mega sheath folds; (2) shear sense indicators along ductile thrust faults formed during their reactivation as sinistral shear zones rather than during thrusting; and (3) peak metamorphic conditions were caused by thrusting and stacking during collision with the Sask craton but were attained later during collision with the Superior craton due to the time lag between orogenesis and the re-equilibration of regional isotherms. Results from this study may be applicable to other complexly deformed terranes where the dominant regional cleavage differs in expression in mixed volcanic and sedimentary successions and has been used as a marker for correlating structures.

Metamorphic and structural evolution of the Flin Flon – Athapapuskow Lake area, west-central Manitoba

The Flin Flon – Athapapuskow Lake area, situated in the Flin Flon Greenstone Belt, Manitoba, consists of ocean-floor and island-arc assemblages, deformed and metamorphosed during the Trans-Hudson Orogeny (∼1.86–1.69 Ga). A new map of metamorphic mineral assemblages and isograds has been compiled that reveals a largely coherent regional metamorphic sequence increasing in metamorphic grade from prehnite–pumpellyite to amphibolite facies. Regional metamorphism postdates most of the deformation within the area, with the exception of the reactivation of major block-bounding faults. The regional prograde sequence has been subdivided into 10 metamorphic zones, separated by 9 isograds, that describe the transition from prehnite–pumpellyite to greenschist to amphibolite facies. The formation of contact metamorphic aureoles, pre-dating regional metamorphism, record conditions up to amphibolite facies. Equilibrium phase diagrams for the island-arc (low-Mg) and ocean-floor (high-Mg) assemblages were calculated and allow for the evaluation of the modelling techniques and determination of pressure–temperature conditions. Discrepancies between the modelling predictions and natural observations occur due to (1) limitations in the thermodynamic models for some of the complex minerals (e.g., amphibole); and (2) metastable persistence of some minerals to higher grade due to sluggish reaction kinetics. Notwithstanding these discrepancies, the modelling suggests that metamorphosed mafic rocks in the Flin Flon – Athapapuskow Lake area reached about 430–480 °C and 3.0–4.5 kbar. Peak metamorphic conditions within contact aureoles that preceded regional metamorphism did not exceed 500 °C (at a pressure between 2.7 and 4.4 kbar). The metamorphic field gradient records a transition from 250–300 °C/1.5–2.3 kbar to 430–480 °C/3–4.5 kbar (100–150 °C/kbar), defining a geothermal gradient of approximately 25–31 °C/km.

Crustal structure of the metasedimentary Kisseynew domain and bounding volcanic–plutonic domains, Trans-Hudson orogen, Canada

The Kisseynew domain (KD) is the largest component of the Paleoproterozoic Trans-Hudson orogen (THO) in Saskatchewan and Manitoba. It is bounded to the north by the Lynn Lake – Leaf Rapids (LL-LR) domain and to the south by the Glennie – Flin Flon (G-FF) complex. The THO was the focus of one of the study areas of Lithoprobe, Canada’s national Earth science research project (1984–2005). To further investigate the crustal structure of the KD and its bounding domains, this study reprocesses reflection line S3a across its northern boundary, analyses four 2.5-D gravity profiles, carries out 3-D gravity inversions for two areas, and replicates results from reflection lines 7 and 10 across the southern boundary of the KD. The reprocessed seismic section enhances the continuity of reflections within the crust. The reflectivity is representative of the complex tectonic development of the boundary zone and clearly identifies a subsurface deformation zone consistent with the boundary. The reflection section also shows that a lower plate (at about 30 to 50 km depth), interpreted as remnant lower crust of the G-FF complex, extends 30 km further northward than in the original section. Lines 7 and 10 illustrate the complex nature of the transition from the KD to the G-FF complex. The gravity analyses show that the variability and complexities of the boundary region between the LL-LR domain and KD, and the G-FF complex and KD, as indicated by the geological and Bouguer gravity maps, extend at depth throughout the crust.

Sources of atmospheric metal(loid) pollution recorded in Thompson Manitoba lake sediment cores within the Canadian boreal biome

Global atmospheric emissions and subsequent deposition of numerous metal(loid)s has increased markedly since the industrial revolution. Due to a paucity of long-term metal(loid) flux measurements, the magnitude and timing of change are largely unknown, resulting in limited ability to predict time-scales of ecosystem recovery in response to emission decreases. In the absence of long-term data, palaeo-reconstructions provide continuous records of atmospheric metal(loid) deposition on an ecosystem, and landscape, scale. Here, we use high-resolution dated lake sediment cores to reconstruct the last c. 100 years of atmospheric anthropogenic deposition of a full suite (40) of metal(loid)s near a large nickel (Ni) and copper (Cu) smelter in an other-wise largely “pristine” region of northern Canada (Thompson, Manitoba). Anthropogenic depositional fluxes were compared to other regions of Canada including Kejimkujik National Park in Nova Scotia, Experimental Lakes Area in Ontario, as well as the Flin Flon, Manitoba Cu and zinc (Zn) smelter, located ~200 km southwest of Thompson. Deposition of 12 metal(loid)s were enriched above baseline (pre-1915) levels: antimony (Sb) > palladium (Pd) > bismuth (Bi) > mercury (Hg) > cadmium (Cd) > Ni > lead (Pb) > arsenic (As) > strontium (Sr) > Cu > platinum (Pt) > Zn. Spatio-temporal patterns in depositional fluxes and inventories demonstrate that 6 of these metal(loid)s were sourced primarily from the smelter, while As, Hg, Pb, Pt, Sb and Zn were sourced primarily from global and/or regional sources. Comparison of anthropogenic fluxes and inventories to available emissions data showed that Cu and Ni deposition has plateaued since the late 1970s despite dramatic smelter emission decreases between 2005 and 2014. We hypothesize that this discrepancy is due to releases of terrestrial metal(loid)s by climate-driven permafrost degradation, which is widespread across the region and will likely continue to drive increased metal(loid) fluxes to northern Canadian lakes for unknown time-scales.

New insights into Paleoproterozoic surficial conditions revealed by 1.85 Ga corestone-rich saprolith

Spheroidally weathered corestones, which are remnant pieces of bedrock surrounded by progressively weathered saprolite, preserve an ideal, small-scale natural interface for examining incipient to intermediate weathering reactions. Ancient corestones are preserved in some Precambrian paleosols but have remained surprisingly understudied. Here detailed mineral-chemical trends are examined across corestone-saprolith interfaces in ca. 1.85 Ga dolerite-hosted paleosol from the Flin Flon-Creighton area (Manitoba and Saskatchewan, Canada). The study presents the first comprehensive paleo-redox tracer suite (Fe-Mn-Mo-U-V-Cr-Ce) for the classic Flin Flon paleosol, which formed during a crucial period in the Paleoproterozoic for which marine sedimentary archives infer a return to low oxygen levels after the Great Oxidation Event (GOE).The textural and mineralogical progression across corestone-saprolith interfaces documented with petrography and scanning electron microscope-mineral liberation analysis (SEM-MLA) show many features (e.g., development of weathering rindlets and solution channels) strikingly reminiscent of modern mafic rock-hosted saprolite, despite later overprint. Albite-dominated cores preferentially preserving carbonate and sulfide (pyrite, chalcopyrite) are progressively altered outwards to a finer-grained saprolith rich in chlorite, illite, and muscovite, with embaying rindlets bearing cryptocrystalline hematite-quartz-illite.These mineral-textural observations guided sub-sampling for bulk Fe(II) and solution ICP-MS ultra-trace and major element analysis, and mineral-scale LA-ICP-MS analysis. Many high-field-strength elements (Al, Ti, Zr, Nb, Hf, Ta, and Th), remained immobile across the interface and ascertain the homogeneity of the parent dolerite. Progressive weathering from corestone to saprolith was quantified with chemical index of alteration minus K (CIA-K) values that fall into three zones (incipient (1): 45–55; modest (2): 55–65; and moderate (3): 65–75). Mass balance and spatial geochemical analysis revealed the following features: outward migration of Fe(II) and Mn from corestone to saprolith, with partial oxidation of Fe(II) to Fe(III) in rindlets; minimal REE mobility with no pronounced Ce anomalies, but well-developed, unidirectional Y/Ho fractionation; significant Cr and V mobility from corestones outwards with enrichment in saprolith; minimal dm-scale cycling and limited loss of Mo and U from saprolith; and post-depositional enrichment of K, Rb, Cs, Tl, Ba, Be, and W. Using semi-quantitative LA-ICP-MS elemental maps, it was possible to contextualize the mineralogical controls on chemical weathering reactions. Iron, Mg, and Mn are coupled within chlorite (representing former pedogenic phyllosilicates), which also scavenged Cr. The REEs are predominantly hosted by apatite and titanite. The Ti-phases ilmenite and titanite are the predominant U- and Mo-bearing hosts.Collectively, the insights from the Flin Flon paleosol converge with those from other ca. 1.90–1.85 Ga terrestrial and marine deposits in inferring an oxygen-limited atmosphere capable of efficiently oxidizing Fe and S, but not Mn, in terrestrial environments. The Cr and V distributions are most consistent with small-scale solubilization and redeposition that appears to be linked to the weatherability of protolith minerals and locally-generated acid- and/or ligand-rich conditions rather than oxidation. Although normally sensitive indicators of oxidative weathering, the inhibited release of Mo and U from the corestone was instead primarily dictated by the weathering resistance of their host minerals. Oxygen-limited weathering in saprolite supplied sulfate to the oceans, but the continental flux of redox-sensitive trace elements from this zone as well as more weathered substrates was limited, ultimately contributing to sustaining a largely redox-dynamic, weakly buffered, and nutrient-limited ocean.

Geochemical constraints on the depositional environment of the 1.84 Ga Embury Lake Formation, Flin Flon Belt, Canada

AbstractThe Flin Flon Belt of Canada contains Paleoproterozoic volcanic–sedimentary sequences that are related to the Trans‐Hudson Orogeny. The sequences include island arc volcanic and volcaniclastic rocks (Amisk Group) that are unconformably overlain by subaerial sedimentary rocks (Missi Group), and younger deep facies sediments. In the Flin Flon area, several north–south trending faults divide the sequences into blocks and obscure the depositional environment of the deep facies sediments. Locally, within the Flin Flon area, the Embury Lake Formation is in fault contact with island arc volcanic–sedimentary sequences of the Amisk and Missi Groups. To identify the depositional environment of the Embury Lake Formation, we used lithologic and geochemical approaches. Here, we report carbon isotopic values in organic matter (δ13Corg) and sulfur isotopes (δ34S), as well as total organic carbon and total sulfur measurements for the black shale in the formation. Samples were taken from a drill core that contains alternating bands of sandstone and black shale. Pyrite in the black shale is divided into four textural types: euhedral, vein‐type, elliptical, and microcrystalline. Microcrystalline pyrite is typically generated by microbially mediated sulfate reduction. An extremely low S/C ratio (avg. = 0.04) is consistent with lacustrine deposition. The ranges of δ13Corg (−36 ‰ to −27 ‰) and δ34S (+3.0 ‰ to +7.7 ‰) values can be explained by bacterial photosynthesis that involved Calvin cycle and acetyl CoA pathways, and sulfate reduction in a low‐sulfate environment. Considering the depositional age reported in a previous study of &lt; 1.84 Ga, the Embury Lake Formation was likely emplaced in a lacustrine setting during the Trans‐Hudson Orogeny.

Ore mineralogy of the Chisel Lake Zn-Cu-Ag (+Au) VMS deposit in the Flin Flon – Snow Lake Domain, Manitoba, Canada

AbstractThe Chisel Lake deposit, in the Flin Flon – Snow Lake Mineral Belt in northern Manitoba, is characterized by an ore mineral assemblage dominated by pyrite and sphalerite, with minor chalcopyrite, galena, and pyrrhotite and trace amounts of other Cu-, Fe-, Sb-, Sn-, As-, Ni-, and Ag-bearing sulfides. Silver is hosted in a variety of Ag-bearing sulfides (chalcopyrite and freibergite–argentotennantite series) and its own sulfide (acanthite).The major elements chemical compositions of the ore sulfides define two populations of sphalerite (Fe-rich and Fe-poor), three populations of chalcopyrite (pure, Ag-rich, and Ag- and Sb-rich), and a typical galena, in addition to pyrite and pyrrhotite. Trace elements are dominated by Mn and Cd for sphalerite; Sn, Zn, and Ge for chalcopyrite; Se and Ni for pyrrhotite; and As and Co for pyrite. Formation temperature was best estimated, from the Fe and trace elements (Ga, Ge, Mn, and In) concentrations in sphalerite, at approximately 340 °C, with other methods giving less reliable temperature and pressure estimates.

Mineral assemblages and phase equilibria of metabasites from the prehnite–pumpellyite to amphibolite facies, with the Flin Flon Greenstone Belt (Manitoba) as a type example

AbstractAn exceptionally well‐exposed part of the Flin Flon Greenstone Belt (Manitoba/Saskatchewan) is used to characterize the mineral assemblage evolution associated with prehnite–pumpellyite through amphibolite facies metamorphism of basalts. Data from these rocks are combined with a large literature data set to assess the ability of current thermodynamic models to reproduce natural patterns, evaluate the use of metabasic rocks at these grades to estimate pressure–temperature (P–T) conditions of metamorphism, and to comment on the metamorphic devolatilization that occurs. At Flin Flon, five major isograds (actinolite‐in, prehnite‐ and pumpellyite‐out, hornblende‐in, oligoclase‐in, and actinolite‐out) collectively represent passage from prehnite–pumpellyite to lower amphibolite facies conditions. The evolution in mineral assemblages occurs in two narrow (~1,000 m) zones: the prehnite–pumpellyite to greenschist facies (PP‐GS) transition and greenschist to amphibolite facies (GS‐AM) transition. Across the GS‐AM transition, significant increases in the hornblende and oligoclase proportions occur at the expense of actinolite, albite, chlorite, and titanite, whereas there is little change in the proportions of epidote. The majority of this mineral transformation occurs above the oligoclase‐in isograd within the hornblende–actinolite–oligoclase zone. Comparison with thermodynamic modelling results suggests data set 5 (DS5) of Holland and Powell (1998, Journal of Metamorphic Geology, 16(3):309–343) and associated activity–composition (a–x) models is generally successful in reproducing natural observations, whereas data set 6 (DS6) (Holland &amp; Powell, 2011, Journal of Metamorphic Geology, 29(3):333–383) and associated a–x models fail to reproduce the observed mineral isograds and compositions. When the data from Flin Flon are combined with data from the literature, two main pressure‐sensitive facies series for metabasites are revealed, based on prograde passage below or above a hornblende–albite bathograd at ~3.3 kbar: a low‐pressure ‘actinolite–oligoclase type’ facies series, characterized by the appearance of oligoclase before hornblende, and a moderate‐ to high‐pressure ‘hornblende–albite type’ facies series, characterized by the appearance of hornblende before oligoclase. Concerning the PP‐GS transition, the mineral assemblage evolution in Flin Flon suggests it occurs over a small zone (&lt;1,000 m), in which assemblages containing true transitional assemblages (prehnite and/or pumpellyite coexisting with actinolite) are rare. This contrasts with thermodynamic modelling, using either DS5 or DS6, which predicts a wide PP‐GS transition involving the progressive appearance of epidote and actinolite and disappearance of pumpellyite and prehnite. Patterns of mineral assemblages and thermodynamic modelling suggest a useful bathograd (‘CHEPPAQ bathograd’), separating prehnite–pumpellyite‐bearing assemblages at low pressures and pumpellyite–actinolite‐bearing assemblages at higher pressures, occurs at ~2.3 to 2.6 kbar. Observations from the Flin Flon sequence suggests devolatilization across the GS‐AM transition (average: ~1.8 wt% H2O) occurs over a very narrow interval within the actinolite–hornblende–oligoclase zone, associated with the loss of &gt;75% of the total chlorite. By contrast, modelling of the GS‐AM transition zone predicts more progressive dehydration of ~2 wt% H2O over a &gt;50°C interval. Observations from the field suggest devolatilization across the PP‐GS transition occurs over a very narrow interval given the rarity of transitional assemblages. Modelling suggests fluid release of 1.0–1.4 wt% resulting from prehnite breakdown over a ~10°C interval. This fluid may not be entirely lost from the rock package due to involvement in the hydration of igneous mineralogy across the PP‐GS transition as observed in the Flin Flon sequence.

Using Clustered Heat Maps in Mineral Exploration to Visualize Volcanic-Hosted Massive Sulfide Alteration and Mineralization

This study proposes an extension of a visualization approach common in biochemistry (the clustered heat maps—CHMs) to geochemical data with the main objective of detecting hydrothermal alteration and mineralization. The approach allows superior visualization of unsupervised cluster analysis results. We consider two examples: a synthetic case study and an application to public data derived from the Canadian Flin Flon volcanic-hosted massive sulfide deposits. A series of experiments were run on a synthetic dataset with the aim of understanding the effect of noise and how random data sampling of variable specimen population size influences results of a variety of clustering algorithms (including K-means and other hierarchical methods) and their visualization using CHMs. These experiments on synthetic data provided the basis to propose a possible workflow for the selection of optimal classifiers to be applied on natural data and the definition of an appropriate parametrization (distance metrics and clustering algorithm). Natural data analysis provides direct evidence of how CHMs can be a fruitful approach in mineral exploration if compared to other cluster analysis methods (e.g., classic K-means or hierarchical methods), CHMs provide the opportunity of examining an additional dimension of clustering and still view chemical compositions (although in a transformed space) in a single plot. Facilitated selection of appropriate levels of granularity (G), which regulates the scale of clustering in a CHM, was found to be an instrumental tool and led to the successful separation of clusters representative of major lithological transitions vs. smaller clusters, at higher granularity, isolating VHMS alteration and mineralization. Integration of statistical tests conducted on synthetic data, together with CHM’s visualization of the classification results led us to consider the Manhattan–Ward classifier as an optimal pair for the Flin Flon dataset, despite its limitations induced by the ‘uniform effect.’

Affective Collections: Care Practices in Digital Community Archives

This paper will present the literature, theoretical framework, and preliminary findings of my MLIS/MA thesis. My research explores how digital community archives use participation-based methods to build a feminist ethics of care into the archival process. These participation-based methods encourage community members to contribute to the collecting, describing, and creating of records. I will use thematic analysis and critical discourse analysis to explore communitymade content associated with the Flin Flon Heritage Project and Harvest Moon Oral History. I am specifically exploring how community archives could enact an ethics of care through the use of care practices in a digital environment.