The tectonomagmatic evolution of the Chibougamau–Chapais area, a peripheral part of the Abitibi belt, is revealed using compiled and new high-resolution geochronological data. Results indicate that volcanism, as old as 2803 Ma and best documented in the 2730–2714 Ma time interval, was dominantly tholeiitic and mafic at first, and progressively became more felsic and calc-alkaline. Melts extracted from mantle and mafic crustal sources formed coeval magmatic systems that hybridized locally to produce diorite. Most large volume tonalite and diorite intrusions assembled at ca. 2720–2714 Ma, as a sagging central volcano got established in the northern half of the Chibougamau–Chapais area and induced deformation (possibly uplift and erosion) in the basalt-dominated southern half of the area. Felsic magmatism then migrated to the south, producing the youngest volcanic unit (ca. 2715 Ma Phooey Member) and tonalite intrusion (ca. 2712 Ma Hazeur pluton) of the area prior to compressional deformation at ca. 2712–2710 Ma. The subsequent time interval is characterized by extension, basin-restricted sedimentation, and by medium to large volume K-enriched magmatism in the upper crust, with magma production peaking at 2697–2695 Ma prior to the main regional north–south shortening event. This is followed by localized extension (stress relaxation) in the central part of the study area and along a WNW-ESE corridor defined by ca. 2688–2685 Ma alkaline magmatism.

The Hammond Reef deposit is located within the south-central region of the Wabigoon subprovince of the Archean Superior province, Canada. The deposit is hosted by the NNE-trending Marmion shear system, which straddles the contact between the 2890.2 ± 1 Ma Diversion stock and ca. 3000 Ma Marmion batholith. The shear system consists of localized fault-controlled zones of white mica (± carbonate) alteration and shearing, superposed on a wider zone of chlorite-carbonate (± white mica) alteration. Multiple shear sense indicators, including the deflection of mylonitic foliations in shear zones, asymmetrical folds, and shear bands, suggest that the Marmion shear system is a major sinistral transcurrent fault system. The deposit occurs along an ENE-trending segment of the Marmion shear system, where it is associated with hydrothermal quartz breccias and quartz-chlorite-carbonate veins, which were emplaced during the white mica (± carbonate) alteration. Gold is present as disseminated grains in the veins and breccias and as microinclusions and fracture fill in pyrite grains within the white mica–altered wall rocks. New monazite U-Pb ages suggest that the deposit formed at ~2700 Ma during the main orogenic event in the Wabigoon subprovince. NNW-directed shortening during this event resulted in sinistral transcurrent displacement along NNE-trending faults of the Marmion shear system and contraction across ENE-trending segments. Increased fracturing and brecciation due to contraction across these segments channelized the migration of hydrothermal fluids and the precipitation and concentration of gold. The ENE-trending segments represent step-over zones at the terminations of en échelon, NNE-trending, transcurrent faults, which became linked by the formation of throughgoing, ENE-trending faults. Thus, Hammond Reef is an excellent example of an orogenic gold deposit that formed in a contractional step-over zone between two right-stepping sinistral transcurrent faults.

Essentially all Archean cratons are fragments of larger pre-existing landmasses, i.e. "supercratons", that stabilized in the late Archean, prior to progressive breakup and dispersal. To fully understand their formation, and the subsequent rifting and breakup processes, we need to take a global view and reconstruct these supercratonic landmasses. One of these supercratons is late Archean Superia, of which the well-preserved Superior craton was a large internal fragment. More than 10 other craton fragments can be reconstructed as "nearest neighbours" to the Superior craton within Superia. Once we have a robust reconstruction, constrained by matches in geology, numerous ages, and paleomagnetic poles, other insights follow that are not apparent from a single-craton perspective. One such insight involves ancient mantle plume tracks with well-defined age progressions. Here we describe two such plume tracks, the Matachewan and Marathon tracks. The Marathon plume track, initiated at ca. 2125 Ma, traversed the southwestern Superior craton before crossing over to the then-contiguous Kaapvaal craton, where it culminated with the emplacement of the Bushveld Complex at 2056 Ma. Paleomagnetic constraints suggest that, at Bushveld time, the Superia plate came to a stand-still, setting up the conditions for the emplacement of Earth's largest layered mafic intrusion.

The eastern Wabigoon superterrane in the Superior Province, Canada, comprises two belts with contrasting tectonic architectures. The Onaman–Tashota belt has a dome-and-keel architecture and consists of granitoid intrusions surrounded by infolded Mesoarchean to Neoarchean (2975–2719 Ma) metavolcanic rocks and younger Neoarchean (2710–2695 Ma) metasedimentary rocks. It is characterized by D 1 fabrics, folds, and deformation zones, which formed parallel to intrusion-volcanic contacts at 2700 to 2683 Ma. The Beardmore–Geraldton belt, located south of the Onaman–Tashota belt, has a linear accretionary architecture and consists of interleaved 2725 Ma metavolcanic rocks and 2700–2694 Ma metasedimentary rocks. Interleaving occurred between 2694 and 2690 Ma during the same D 1 event. Orogen-parallel D 2 folds, cleavage, and sinistral deformation zones overprint the D 1 structures in both belts. They formed between 2683 and 2665 Ma at transitional greenschist to amphibolite facies temperatures > 515 °C in the Onaman–Tashota belt, and greenschist facies temperatures in the Beardmore–Geraldton belt. D 3 dextral transpression occurred late and reactivated early D 1 –D 2 deformation zones in both belts. Although the two belts underwent the same sequence of deformation events, the coeval development of dome-and-keel and linear accretionary structures suggests that different factors controlled the development of D 1 structures. Higher density contrasts, hotter weaker crust, and possibly lower strain rates in the Onaman–Tashota belt resulted in the formation of uniformly distributed dome-and-keel structures, while lower density contrasts, strong planar anisotropies, and possibly higher strain rates favored the development of linear accretionary structures in the Beardmore–Geraldton belt.

Volcanogenic massive sulfide (VMS) deposits with advanced argillic alteration display characteristics typical of conventional VMS and high-sulfidation epithermal deposits. Unlike conventional VMS deposits, these “hybrid” VMS are interpreted to have formed through a magmatic fluid contribution to an evolved, seawater-dominated, hydrothermal system. The close spatial association of advanced argillic alteration assemblages with more typical chlorite–sericite assemblages in the same VMS deposit has implications for the controls on magmatic versus seawater convective systems that have not been previously addressed in the literature. The Neoarchean Onaman assemblage (ca. 2780–2769 Ma) in northwestern Ontario hosts a conventional base metal VMS system with chlorite–sericite alteration that is overprinted by argillic and advanced argillic alteration, now manifested as a metamorphosed zone of kyanite–chloritoid–calcite–Fe–chlorite, that is associated with a barren, pyritic VMS deposit. The change from typical to advanced argillic alteration occurred during, or immediately following, the deposition of a tonalite clast-bearing heterolithic breccia, which recorded the uplift and subaerial exposure of the larger volcanic edifice. We postulate that the reactivation of synvolcanic structures during uplift, concomitant localized subsidence, and magmatism enhanced cross-stratal permeability and allowed for a direct magmatic volatile input into, or overprint on, an evolved seawater-dominated hydrothermal system. Our results suggest that geodynamic regimes exert a strong local, and possibly regional, control on the style, timing, and fluid characteristics of VMS hydrothermal systems. The association of advanced argillic alteration with barren pyritic massive sulfide also suggests that magmatic volatile input alone is not sufficient to enrich VMS systems in gold. This interpretation is consistent with observations from other magmatic–hydrothermal systems such as porphyry and epithermal deposits.

Epithermal precious metal deposits are uncommon within the Archean rock record, as are detailed descriptions of their associated features and modes of formation. The Vent prospect is a Neoarchean Au–Ag occurrence within the Eastern Wabigoon Subprovince of the Superior Province in Ontario. It is hosted by aphyric, and quartz ± feldspar-porphyritic aphanitic dacitic flows that show remnants of spine-like structures within blocky flow top breccia facies that lack visible hyaloclastite, consistent with subaerial emplacement. Numerous phreatic breccia dikes containing rounded, heterolithic, fragments in a fine rock flour and locally altered matrix intrude the dacitic host rocks, supporting a subaerial setting. Discordant replacement and stringer Au- and Ag-bearing pyrite mineralization is associated with a decimeter-scale, zoned, discordant sequence of metamorphic associations consisting of a) quartz-pyrite; b) kyanite-quartz; c) muscovite-kyanite; and d) muscovite. The geochemical characteristics of these metamorphic associations reflect intense pre-metamorphic acidic alteration. These lithofacies, alteration characteristics, and mineralization styles are consistent with a subaerial volcanic edifice altered by acidic hydrothermal fluids, which periodically brecciated the edifice. We propose that the features that characterize the Vent prospect are consistent with those of Phanerozoic epithermal systems. New U–Pb zircon geochronology of the host dacites indicate formation at ca. 2720 Ma, suggesting that the Vent prospect may represent one of the oldest identified epithermal deposits preserved in the ancient rock record. The recognition of epithermal mineralization in Archean greenstone belts underlain by Mesoarchean crust, such as those of the Eastern Wabigoon, opens up the possibility of potential for gold and silver in other underexplored Archean greenstone belts.

The Neoarchean diorite- and tonalite-dominated Chibougamau pluton (Canada) is ideal for case studies dedicated to the petrogenesis and timing of emplacement of fertile magmatic systems and associated Cu-Au porphyry systems. Using whole-rock analyses, geochronology, and zircon chemistry, it is determined that an early magmatic phase (pre-2714 Ma) is derived from a dioritic magma with a moderate ƒO2 (ΔFMQ 0 to +1), which is optimal for transporting Au and Cu, and that diorite is a potentially fertile magma. Field descriptions indicate that the main mineralizing style consists of sulfide-filled hairline fractures and quartz–carbonate veins. This is likely the consequence of fluid circulation facilitated by a well-developed diaclase network formed following the intrusion of magma at about 4–7 km depth in a competent hosting material. The petrographic features of fluid inclusions (FIs), considered with their microthermometric data and evaporate mound chemistry, suggest the exsolution of early CO2-rich fluids followed by the unmixing of later aqueous saline fluids characterized by a magmatic signature (i.e., Na-, Ca-, Fe-, Mn-, Ba-, and Cl-F). The type of magmatism and its oxidation state, age relationships, the nature of mineralization, and fluid chemistry together support a model whereby metalliferous fluids are derived from an intermediate hydrous magma. This therefore enforces a porphyry-type metallogenic model for this Archean setting.

The Rouyn-Noranda mining district of Quebec contains 20 Cu-Zn (+/- Au +/- Ag) volcanogenic massive sulfide (VMS) deposits, including the giant and gold-rich Quemont and Horne deposits. Mineralized epigenetic veins are also present, but their origin and relative timing remain enigmatic. The nature and extent of their alteration signatures and the effect of their superposition on district-scale alteration patterns is unknown. The VMSrelated quartz-sulfide Cu-Zn-Ag veins have delta O-18(quartz) values of 8.5 +/- 0.8 parts per thousand, reflecting delta O-18(fluid) compositions of -0.4 to 3.1 parts per thousand (250 degrees-350 degrees C) that are typical of Archean seawater. They are associated with a proximal Fe-rich chlorite alteration and marginal spotted sericite-chlorite alteration with whole-rock delta O-18 values of 2.9 to 5.9 parts per thousand and are interpreted to have formed within the structurally controlled discordant upflow zones of a VMS hydrothermal system. Younger gold-bearing quartz-carbonate veins were emplaced along mechanical anisotropies created by mafic dikes during north-south compression and the formation of regional E-trending faults, folds, and cleavage. They are characterized by delta O-18(quartz) values of 11.3 +/- 0.8 parts per thousand, reflecting delta O-18(fluid) compositions of 2.4 to 5.9 parts per thousand (250 degrees-350 degrees C), typical of a metamorphic fluid, possibly mixed with a lower delta O-18 upper crustal fluid. They are associated with ankerite, calcite, muscovite, chlorite, albite, and quartz +/- hematite alteration with whole-rock delta O-18 values of 5.8 to 10.3 parts per thousand. Chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb zircon ages for two tonalite intrusions constrain the maximum age of the Cu-Zn-Ag veins to 2697.6 +/- 0.7 Ma and the minimum age to 2695.3 +/- 1.0 Ma, which is also the maximum age of the gold quartz-carbonate veins. Superposition of alteration related to the gold quartz-carbonate veins on previously chlorite- and sericite-altered rocks has resulted in mixed alteration signals with whole-rock delta O-18 values of similar to 6 to 8 parts per thousand that have perturbed and masked regional alteration patterns related to older VMS mineralization, such as those found in the Quemont and Horne deposits. These results indicate that defining alteration vectors in camps that have superimposed hydrothermal systems requires full consideration of the hydrothermal history of the camp, and if such constraints are lacking, whole-rock delta O-18 values should not be used as a stand-alone exploration method.

Abstract Avalonian sections in the Saint John area, southern New Brunswick, have long contributed to global understanding of Cambrian chronostratigraphy. A tuffaceous bed in the Ratcliffe Brook Formation (RBF) in the Somerset Street section dated at c. 531 Ma has traditionally been considered to post-date small shelly fossils attributed to the Watsonella crosbyi Zone in the Hanford Brook section. A fine-grained tuffaceous bed approximately 8 m stratigraphically lower in the Somerset Street section yields a chemical abrasion isotope dilution–thermal ionization mass spectrometry zircon age of 532.3 ± 0.3 Ma; a tuffaceous carbonate unit in the lower RBF in Hanford Brook gives an age of 531.5 ± 0.3 Ma. Crystal and crystal-lithic tuff beds near the top of the RBF yield ages of 520.3 ± 0.3 Ma (in Hanford Brook) and 519.1 ± 0.3 Ma (in Ratcliffe Brook). The new ages confirm the correlation between the Somerset Street and Hanford Brook sections based on acritarchs and make the association of small shelly fossils in the Hanford Brook section younger than 531 Ma. This result is relevant to ongoing discussions on the age of the base of undefined Cambrian Stage 2. The radiometric ages also support a young age for the upper part of the RBF, perhaps extending into Epoch 2.

Background In response to the rise in opioid-related deaths, communities across Ontario have developed opioid or overdose response plans to address issues at the local level. Public Health Ontario (PHO) leads the Community Opioid / Overdose Capacity Building (COM-CAP) project, which aims to reduce overdose-related harms at the community level by working with communities to identify, develop, and evaluate capacity building supports for local needs around overdose planning. The ‘From Design to Action’ co-design workshop used a participatory design approach to engage communities in identifying the requirements for capacity building support. Methods A participatory approach (co-design) provided opportunity for collaborative discussion around capacity building needs at the community level. The co-design workshop included three structured collaborative activities to 1) prioritize scenarios that illustrated various challenges associated with community overdose response planning, 2) prioritize the challenges within each scenario and 3) prioritize the supports to address each of these challenges. It was conducted with fifty-two participants involved in opioid/overdose-related response plans in Ontario. Participatory materials were informed by the results of a situational assessment (SA) data gathering process, including survey, interview, and focus group data. A voting system, including dot stickers and discussion notes, was applied to identify priority supports and delivery mechanisms. Results At the workshop, key challenges and top-priority supports were identified, for development and implementation. The prioritized challenges were organized into five categories of capacity building supports addressing: 1) stigma & equity; 2) trust-based relationships, consensus building & on-going communication; 3) knowledge development & on-going access to information and data; 4) tailored strategies and plan adaptation to changing structures and local context; and 5) structural enablers and responsive governance. Conclusion Using a participatory approach, the workshop provided an opportunity for sharing, generating, and mobilizing knowledge to address research-practice gaps at the community level for opioid response planning. The application of health design methods such as the ‘From Design to Action’ co-design workshop supports teams to gain a deeper understanding of needs for capacity building as well as illustrating the application of participatory approaches in identifying capacity building needs for complex public health issues such as the overdose crisis.

During the Cryogenian (720 to 635 Ma ago) Snowball Earth glaciations, ice extended to sea level near the equator. The cause of this catastrophic failure of Earth’s thermostat has been unclear, but previous geochronology has suggested a rough coincidence of glacial onset with one of the largest magmatic episodes in the geological record, the Franklin large igneous province. U-Pb geochronology on zircon and baddeleyite from sills associated with the paleo-equatorial Franklin large igneous province in Arctic Canada record rapid emplacement between 719.86 ± 0.21 and 718.61 ± 0.30 Ma ago, 0.9 to 1.6 Ma before the onset of widespread glaciation. Geologic observations and (U-Th)/He dates on Franklin sills are compatible with major post–Franklin exhumation, possibly due to development of mafic volcanic highlands on windward equatorial Laurentia and increased global weatherability. After a transient magmatic CO2 flux, long-term carbon sequestration associated with increased weatherability could have nudged Earth over the threshold for runaway ice-albedo feedback.

The current body of literature lacks studies related to organizational managers' classification of systems thinking (ST) skills based on both their overall systemic tendency and the organizational ownership structure. The purpose of this study is to assess and classify the ST skills of senior managers who currently work in a complex business environment. Initially, we clustered managers' overall systemic thinking (OST) using the Bayesian latent class analysis (BLCA) method into two distinct clusters: managers with upper OST (holistic thinker) and managers with lower OST (reductionist thinker). Further, we classified managers' ST skills into two predefined classes to understand the characteristics of each group better. A total of 51 senior managers from two different organizational structures participated in this study. Results show that the ST skills of managers in public are more towards the upper OST/holistic cluster, whereas managers from the private sector have an inclination towards lower OST/reductionist cluster.

Background Many communities across North America are coming together to develop comprehensive plans to address and respond to the escalating overdose crisis, largely driven by an increasingly toxic unregulated drug supply. As there is a need to build capacity for successful implementation, the objective of our mixed methods study was to identify the current planning and implementation practices, needs, and priority areas of support for community overdose response plans in Ontario, Canada. Methods We used a situational assessment methodology to collect data on current planning and implementation practices, needs, and challenges related to community overdose response plans in Ontario, consisting of three components. Between November 2019 to February 2020, we conducted ten semi-structured key informant interviews, three focus groups with 25 participants, and administered an online survey ( N = 66). Purposeful sampling was used to identify professionals involved in coordinating, supporting, or partnering on community overdose response plans in jurisdictions with relevant information for Ontario including other Canadian provinces and American states. Key informants included evaluators, representatives involved in centralised supports, as well as coordinators and partners on community overdose response plans. Focus group participants were coordinators or leads of community overdose response plans in Ontario. Results Sixty-six professionals participated in the study. The current planning and implementation practices of community overdose response plans varied in Ontario. Our analysis generated four overarching areas for needs and support for the planning and implementation of community overdose response plans: 1) data and information; 2) evidence and practice; 3) implementation/operational factors; and 4) partnership, engagement, and collaboration. Addressing stigma and equity within planning and implementation of community overdose response plans was a cross-cutting theme that included meaningful engagement of people with living and lived expertise and meeting the service needs of different populations and communities. Conclusions Through exploring the needs and related supports for community overdose response plans in Ontario, we have identified key priority areas for building local capacity building to address overdose-related harms. Ongoing development and refinement, community partnership, and evaluation of our project will highlight the influence of our supports to advance the capacity, motivation, and opportunities of community overdose response plans.

Magmatism during the maturation phase of Archean greenstone belts produced voluminous tonalite–trondhjemite–granodiorite (TTG) suites, as well as a lesser amount of tonalite–trondhjemite–diorite (TTD) suites. Such TTD suites have recently been recognized in the Archean Abitibi greenstone belt, on the southern flank of the Superior Craton, Canada, but their source(s), differentiation processes, and depths of emplacement remain poorly constrained. The Neoarchean Eau Jaune Complex lies in the northeastern corner of the Abitibi greenstone belt and represents one of the most voluminous tonalite-dominated and diorite-bearing intrusive suites of the Chibougamau region. This TTD suite comprises six intrusive phases with distinct petrology and chemistry. All units were emplaced as laccolith-like intrusions injected along discontinuities within the volcanic succession at ca. 2724 Ma (U–Pb zircon dating), during the synvolcanic interval (i.e., construction and maturation phase), at a depth of approximately 7–8 km. The most heavy rare-earth element (HREE)-depleted phases (granodiorite, tonalite, and trondhjemite) correspond to magmas that fractionated amphibole and were likely produced by partial melting of a garnet- and titanate-bearing amphibolite, akin to TTG magmas. The least HREE-depleted phases are dioritic in composition and correspond to mantle-derived magmas that may have interacted with TTG melts. This indicates interaction between coeval mantle-derived and crustal melts during the maturation phase of the Abitibi greenstone belt. Models formulated to address the geodynamic evolution of greenstone belts must account for the coeval production of basalt-derived (TTG suites) and mantle-derived (tholeiitic magmatism) melts occasionally interacting to form TTD suites.

The focus of computer systems in the field of visual analytics is to make the results clear and understandable. However, enhancing human-computer interaction (HCI) in the field is less investigated. Data visualization and visual analytics (VA) are usually performed using traditional desktop settings and mouse interaction. These methods are based on the window, icon, menu, and pointer (WIMP) interface, which often results in information clutter and is difficult to analyze and understand, especially by novice users. Researchers believe that introducing adequate, natural interaction techniques to the field is necessary for building effective and enjoyable visual analytics systems. This work introduces a novel virtual reality (VR) module to perform basic visual analytics tasks and aims to explore new interaction techniques in the field. A pilot study was conducted to measure the time it takes students to perform basic tasks for analytics using the developed VR module and compares it to the time it takes them to perform the same tasks using a traditional desktop to assess the effectiveness of the VR module in enhancing student’s performance. The results show that novice users (Participants with less programming experience) took about 50% less time to complete tasks using the developed VR module as a comrade to a programming language, notably R. Experts (Participants with advanced programming experience) took about the same time to complete tasks under both conditions (R and VR).

Thousands of people work in the precast/pre-stressed concrete industry every day. Due to the design of the precast/prestressed concrete product itself and the processes required for its production, employees are occasionally exposed to hazards. The industry recognizes this and devotes a significant amount of time and investment to mitigate these hazards and protect employees from harm. It is essential for employees to go through appropriate safety training before starting work in the plant. Practical safety training should be cost-effective, and performance guaranteed, and traditional training procedures include paper-based safety guidelines, lectures, videos, and on-site training. Virtual Reality (VR) provides an innovative approach for safety training as it could offer situational training with negligible risk and at a low cost. In this paper, a VR training module is developed to deliver safety training in a cost-effective yet repeatable manner, aiming to reduce common plant injuries. The module is developed using Unity3D and Visual Studio joint platforms and can be interfaced with using the Oculus Rift/Oculus S. The module addresses three major safety concerns in the plant: personal protective equipment (PPE), the tensioning of strand (the stressing process), and suspended loads. Efficacy and effectiveness analyses were conducted to evaluate the performance of the proposed VR module. The efficacy analysis was based on simulation sickness, user experience, and system usability. This analysis showed that the developed VR module is a user-friendly simulator with minimal simulation sickness. More than 50% of the participants reported no indications of simulation sickness. In addition, an effectiveness analysis was performed based upon a comparative study of this VR training method and the traditional video-based training method. This analysis indicated that VR training is more engaged and provides a better understanding of safety protocols and real-life experience of the precast/prestressed concrete plant.

Nowadays, with the increasing complexity of vehicle operating environment, vehicle operating reliability becomes growing essential and has attracted significant attention in recent decades. The majority of vehicle operating activities are organized in the format of time series data. Many conventional approaches are proposed to deal with time-series data. Autoregressive Integrated Moving Average (ARIMA) approach is one of the most widely used methods to analyze time-series data. In this paper, an ARIMA-based anomaly detection framework is developed to identify abnormal states of the vehicles based on the multiple-channel operating time series data. The state anomaly is captured by the deviation of real-time values at different channels from the predictions. After abnormal operating states are identified, a novel immersive Virtual Reality (VR) tool is applied to visualize the difference between normal and abnormal status. The combination of ARIMA anomaly detection and VR visualization for vehicle multiple-channel operating time-series data would provide a robust way to present the results of vehicle operating status. A large scale data set of 14 days operational performance channels of a specific vehicle is utilized to validate the performance of the proposed approach.

Our understanding of crustal architecture and tectonic evolution has advanced due to integrated geological and geophysical research on Precambrian cratons. However, it is still a heated debate whether Archean crust structure developed by an allochthonous model similar to modern plate tectonics or autochthonous model emphasizing in-situ evolution of supracrustal belts. The < ca. 2696 Ma Chicobi belt is a sedimentary basin in the central Abitibi Subprovince of the Superior Province, and as such provides a unique opportunity to contribute to this debate. It comprises both Porcupine-type turbidite and Timiskaming-type polymictic conglomerate and cross-bedded sandstone, and unconformably overlies ca. 2728-2711 Ma metavolcanic rocks, including the Amos Group to the south. The metasedimentary rocks were deposited after an early (D-1 > ca. 2696 Ma) deformation event, which is expressed by internally foliated clasts in conglomerate. The Chicobi belt was regionally folded and cut by shear zones during a second (D-2) deformation event, and was re-folded by Z-shaped folds during a third (D-3) dextral shearing event. The D-2 event is constrained between ca. 2696 Ma, the pre-existing age of detrital zircon in the Scapa Group along strike of the Chicobi belt, and ca. 2681 Ma, the new age of the crosscutting syenitic Gemini-Saint-Eloi Pluton. New high-resolution seismic reflection and magnetotelluric surveys were conducted along the same transect across the Chicobi belt. The seismic reflection survey imaged subhorizontal to shallowly north-dipping reflective bands at depths of 3-7 km. Regional-scale inversion of new and pre-existing gravity data indicates that these reflective bands are linked to the Beauchamp Fault south of the Amos Group. Magnetotelluric inversion model shows high resistivity (>1000 Omega.m) zones under metasedimentary rocks, as well as a synform defined by low resistivity (10-100 Omega.m) zones, which aligns with folded metavolcanic rocks south of the Chicobi belt. Integration of the geophysical data with surface mapping suggests that the upper-middle crustal architecture of the Chicobi belt is dominated by D-2 upright folds overlying a fault zone. We suggest that deformation of the Chicobi belt is dominated by thrusting and folding, a deformation style compatible with allochthonous growth of the Abitibi Subprovince.

Unravelling the petrogenesis and stratigraphy of Archean mafic lava flows is essential to our comprehension of the early geodynamic evolution and economic potential of greenstone belts. This study focuses on one of the oldest and thickest sequences of lava flows observed in the Neoarchean Abitibi Subprovince (greenstone belt), that is, the Obatogamau Formation. The undated formation extends for more than 100 km in an E–W direction and consists mostly of aphyric and feldspar megacryst-bearing basaltic-andesite lava flows. These lava flows are tholeiitic, mostly Fe-rich, and have nearly homogeneous chemistry. Petrogenetic modelling carried out using MELTS software points to limited magmatic differentiation as most samples of mafic lava flows did not reach Fe-Ti-oxide saturation. Zircon U-Pb dating establishes a crystallization age of 2726.2 ± 1.6 Ma for a felsic unit located at an intermediate stratigraphic position in the sequence of lava flows. Constraints from stratigraphically overlying volcanic units suggest that the Obatogamau Formation was likely emplaced rapidly, possibly within a few million years and as a consequence of frequent replenishment of shallow magma accumulations. High eruption rates are consistent with short episodes of volcanic quiescence deduced from field observations, indicating non-optimal conditions for volcanogenic massive sulfide systems. The pressure and temperature of peak metamorphism deduced from amphibole chemistry, however, points to favorable conditions for the release of metamorphic fluids. The study area may thus be prospective for orogenic gold mineralization, provided that fluids had access to a source of gold and that structural conduits allowed for the channeling of hydrothermal fluids.