Geological Survey of Canada

Snow albedo modulates net solar radiation, influencing snowmelt timing and magnitude, which is critical to watershed ecosystems and downstream communities. Snow grain size, a primary control on albedo, can be derived from near infrared lidar reflectance, a potentially valuable supplement to altimetry data. However, converting raw lidar intensity to reflectance is complex, with several existing methods but no comprehensive accuracy comparison to date. To address this gap, we leverage data from the Airborne Coastal Observatory (ACO), a paired lidar and imaging spectrometer platform, collected on May 15, 2021, over the snow-covered Place Glacier in the Coast Mountains of British Columbia, Canada. Three methods used to derive reflectance from the Riegl 1064 nm lidar were assessed, including: (1) an independent range and incidence angle correction (LR IC ); (2) the vendor product that accounts for range (LR riegl ); and (3) the vendor product with an additional incidence angle correction (LR rieglθ ). Radiative transfer modeling and lidar reflectance were used to derive grain size and the associated theoretical clean snow albedo. Reflectance and property retrievals were assessed against those derived from the imaging spectrometer (Specim Fenix). Reflectance magnitude of LR IC and LR rieglθ were similar in reflectance magnitude to the spectrometer but displayed greater variability. Grain sizes were underestimated (∼136 μm) producing a median relative error in albedo of 2%. LR riegl was positively biased, with greater underestimation of grain size (455 μm) and higher albedo error (6%). Results highlight the necessity of incorporating incidence angle corrections when using lidar for surface reflectance retrievals in mountainous terrain and further demonstrate the potential of lidar intensity for high-resolution snow grain size estimation. • We compare snow surface properties from lidar intensity to imaging spectroscopy. • Spatial comparison over a mountain glacier included variable snow conditions. • Range and incidence angle corrections produced comparable reflectance. • Manufacturer-provided reflectance (range corrected) compared poorly. • Relatively small errors in reflectance produced larger errors in grain size.

Precise seafloor geodetic measurements are essential for understanding plate tectonics, earthquake cycles, and volcanic activity. Seafloor pressure gauges provide a key tool for monitoring vertical changes in the seafloor elevation. However, distinguishing millimeter-scale tectonic signals from instrumental drift and environmental noise remains a fundamental challenge in deep-ocean observing.This presentation evaluates the performance and data integrity of self calibrating bottom pressure recorders (BPR) deployed by Ocean Networks Canada (ONC) offshore Vancouver Island. Instruments like the RBR BPRZero and the Sonardyne FETCH AZA utilize Ambient-Zero-Ambient (AZA) in-situ calibration mechanisms to quantify sensor drift. The AZA method involves switching a pressure gauge from ambient (seafloor) pressure to atmospheric pressure within the instrument's housing. By comparing this internal pressure reading to an accurate barometer also measuring internal pressure, the drift can be precisely determined and a calibration function applied.A forensic analysis of the dataset reveals that, while the high-resolution pressure measurements capture true genuine environmental signals, they are also significantly contaminated by instrumental artifacts that are partially related to the measurement approach itself. In this study we report findings from preliminary deployments and discuss the methodological challenges encountered, proposing mitigation strategies for future applications.

The west-central Keewatin region of northern Canada preserves a rich record of former ice sheets and their impact on the landscape. The diverse assemblage of glacial landforms in the region reflects spatial variations in glacial modification driven by changes in basal thermal regime, subglacial hydrology, and ice-flow dynamics, all of which are key to reconstructing the history and behaviour of palaeo-ice sheets. Resolving how these landforms relate to changes in basal regime and glacial modification requires integrated datasets such as geomorphological mapping and to provide the robust reconstructions needed for climate and ice-sheet models.Our work aims to provide both a qualitative and quantitative assessment of glacial landscape modification in the west-central Keewatin region of the Northwest Territories and mainland Nunavut using two independent proxies: geomorphic mapping and cosmogenic nuclide concentrations. We used the ArcticDEM and Landsat 8 imagery to remotely map This new inventory of landforms, integrated with existing mapping, provides a qualitative assessment of glacial landsystems and landscape modification across the Keewatin region. As a quantitative proxy for glacial modification from the last glacial period(s), we collected 10 bedrock and 7 boulder samples for cosmogenic 10Be measurement along a north-south transect east of Dubawnt Lake, Nunavut. The sample transect was informed by glacial geomorphic mapping and was selected to test field-based predictions of the degree of landscape modification from the previous glaciation(s). The northern portion of the transect contains high concentrations of streamlined landforms associated with the onset zone of the Dubawnt Ice stream, inferred to be a region of high glacial modification. In contrast, the southern end of the transect contains lower concentrations of streamlined features, flow sets with contrasting orientations, and cross-cutting striations, suggesting a higher degree of landscape preservation during the last glaciation(s). Preliminary 10Be results broadly confirm our initial assessment of glacial modification along our transect, revealing slightly higher concentrations of 10Be in the south (less modification) and decreasing 10Be concentrations towards the north (more modification). Both bedrock and boulder samples follow this trend, however, our results show that in both low- and high-modification landsystems, some samples retain significant nuclide inheritance, including some boulders which suggests transport from a less modified landscape. Combining qualitative and quantitative approaches to evaluate glacial modification associated with specific landform assemblages informs our understanding of the basal thermal conditions of palaeo-ice sheets, the distribution of which informs our understanding of ice sheet evolution through space and time. Furthermore, the identification of streamlined features into palaeo-flow sets supports potential mineral exploration by helping to determine glacial transport directions and dispersal patterns. However, our results show the concentrations of cosmogenic nuclides vary within individual landsystems, suggesting that glacial modification varied through time and can be influenced by multiple factors (e.g., subglacial thermal conditions, topography, glacio-isostatic adjustment, lake development) that remain to be quantified.

Abstract Objective Test whether dietary differences among hatchery strains of Lake Trout Salvelinus namaycush were associated with variation in egg thiamine concentrations and assess the potential for using strain-specific traits to mitigate thiamine deficiency complex (TDC) in Lake Ontario restoration efforts. Methods Stomach content analysis and stable isotope mixing models were used to compare diets among four hatchery strains of Lake Trout, representing lean and humper morphotypes. Egg thiamine concentrations were measured to test whether dietary differences correlated with susceptibility to TDC. Results Significant differences in diet and egg thiamine concentrations were observed among Lake Trout strains. A humper-like morphotype strain exhibited elevated thiamine levels, which were associated with reduced consumption of prey known to degrade thiamine levels when consumed, Alewife Alosa pseudoharengus and Rainbow Smelt Osmerus mordax, and increased reliance on Round Goby Neogobius melanostomus or sculpin species (Slimy Sculpin Cottus cognatus and Deepwater Sculpin Myoxocephalus thompsonii). These findings support the link between the consumption of Alewife and Rainbow Smelt and thiamine deficiency. Conclusions Our findings support a link between strain-specific dietary preferences and susceptibility to TDC in Lake Trout. Preferential stocking of strains less prone to TDC, such as the strain derived from a humper morph from Lake Superior, could enhance restoration success in Lake Ontario. This strategy may be especially effective given the continued dominance of Alewife in the lake's prey base and the current management priorities supporting fisheries for Pacific salmon Oncorhynchus spp.

• First methodology for predicting greenhouse gas emissions from mineral exploration. • Upstream mineral exploration industry classified into six key work activities. • Example greenhouse gas inventory as well as data products for decision-making. Reaching global climate targets and the energy transition will require new sources of critical minerals. Exploration and mining activities generate greenhouse gas (GHG) emissions, but the relative contribution of emissions from all portions of the mining value chain remains poorly understood. Here, we divide the upstream portion of the mining value chain (i.e., mineral exploration) into six activities, representative of most Scope 1 emissions. We present spatial methods to estimate GHG emissions for ground and air transport and apply these methods to constrain emissions of three of the six exploration activities. A ground-transport model is informed by a spatial network analysis finding least-cost paths and fuel economy; whereas the air-transport model is informed by straight-line proximity to start locations and aircraft burn rate. We use these models in two applications. First, producing continuous maps of a single exploration activity with an example of field work mobilisation in British Columbia, Canada (i.e., mobilising a single vehicle) that can be used in a comparative fashion, where emissions of the activity can be compared between any two points in the modelling area. Second, a detailed emissions estimation contrasting two hypothetical drill programs, analogous to a GHG inventory when fuel use is not detailed in exploration reports. The methods and example data products presented here demonstrate how large-scale emissions inventories could be completed for the upstream exploration sector and used to define exploration areas prospective for critical minerals that will generate the lowest amount of GHG emissions.

Responsible hydraulic fracturing is important for the future of Canada's oil and gas sector. Hydraulic fracturing operations use significant amounts of water. The flowback and produced water from hydraulic fracturing operations contain toxic chemicals and is stored on site. Alberta Energy Regulator records hundreds of surface spills of flowback and produced water per year. Nevertheless, to promote water reuse during hydraulic fracturing operations and reduce costs, industry uses fit-for-purpose water treatment methods to treat the flowback and produced water, targeting suspended solids and dissolved solids. In addition, the recent interest in the lithium content in hydraulic fracturing flowback and produced water has stimulated direct lithium extraction technology development across Canada. However, most of these technologies require a certain degree of organic removal. Traditional water treatment technologies are costly, and as such, further development in low-cost water treatment techniques is crucial to treat and reuse flowback and produced water. In this study, we utilized waste materials (i.e., petroleum coke) from the oil sands industry for hydraulic fracturing flowback and produced water treatment by employing an in-house coke activation method. Flowback and produced water samples from different locations in the Western Canadian Sedimentary Basin were analyzed and compared using a suite of analytical techniques. Dissolved organics were analyzed by high-resolution mass spectrometry using nontargeted analysis methods. The organic and iron removal efficiencies of different activated carbon products were compared. Results indicate that the surface area of coke is the primary factor influencing its adsorption capacity for dissolved organics; however, it does not significantly impact the efficiency of iron removal. Overall, this study demonstrated the potential of using petroleum coke for treating flowback and produced water, laying grounds for development of low-cost treatment technologies.

SUMMARY Accurate characterization of the magnitude–frequency distribution of seismicity, and its associated uncertainties, is essential for seismic hazard assessment. This distribution is commonly described by the Gutenberg–Richter (GR) relation, parametrized by the b-value, which has been identified as a potential proxy for investigating many spatiotemporally varying Earth phenomena. Estimating the spatiotemporal variability of b-values often requires windowing, forcing a trade-off between resolution and statistical reliability. New probabilistic methods circumvent this by inferring both the number and locations of change points directly from earthquake catalogues. Nevertheless, accurately determining the b-value remains difficult because the GR relation only holds over a limited range of magnitudes. This research develops a general statistical model to address several methodological challenges in estimating the magnitude–frequency distribution of observed seismicity, including variations in space or time. The approach simultaneously solves for the b-value and magnitude-range limits. This avoids potential bias due to inaccurate manual truncation of earthquake catalogues. The model considers the entire observed catalogue and parametrizes the decay of the distribution at both low and high magnitudes. Consequently, robust uncertainties in estimated b-values reflect uncertainty in the range of magnitudes over which the GR relation is observed to be valid. Importantly, spatiotemporal variations in the parameters that define the magnitude range are considered to be independent from the b-value, as we assume the physical factors that influence the GR relation are independent of the factors that limit the observed earthquake catalogue. We demonstrate this methodology through application to simulated and observed earthquake catalogues. In particular, the value of our approach is highlighted through application to observed records of induced seismicity associated with fluid-injection operations in western Canada. Our results demonstrate accurate b-value estimates and associated uncertainties. Furthermore, the additional parameters that define the magnitude range serve as proxies for other factors including seismic network performance, recording duration, potential geometric limitations on earthquake size and potential injection characteristics (in induced seismicity cases). Our approach also allows for the investigation of how these other factors may vary in space/time. Results from this work contribute to rigorous propagation of accurate b-value estimates, including uncertainties, into subsequent analyses such as seismic hazard models and regulatory protocols that are applied to industrial activity.

Technological innovation in commercial Remotely Piloted Aircraft Systems (RPASs) is advancing rapidly. However, their operational efficiency remains limited by the need for on-site skilled human operators. Semi-autonomous drone-in-a-box (DIAB) systems are emerging as a practical solution, enabling automated, repeatable missions for applications such as construction site monitoring, security, and critical infrastructure inspection. Beyond industry, these systems hold significant promise for scientific research, particularly in long-term environmental monitoring where cost, accessibility, and safety are critical factors. In this technology demonstration, we detail the system implementation, discuss flight-planning challenges, and assess the overall feasibility of deploying a DJI Dock 2 DIAB system for remote monitoring of the Miles Ridge landslide in the Yukon Territory, Canada. The system was installed approximately 2.5 km from the landslide and operated remotely from across the country in Montreal, QC, about 4000 km away. A total of five datasets were acquired from July to September 2025, enabling three-dimensional reconstruction of the landslide surface from each acquisition. A comparison of extracted cross-sections demonstrated high reproducibility and accurate co-registration across acquisitions. This study highlights the potential of DIAB systems to support reliable, low-maintenance monitoring of remote landslides.

Establishing the timing and duration of magmatism, mineralization, and deformation leading to the development of porphyry systems is key to identifying prospective regions within orogenic belts. The Blue Property in the Atlin Lake area in northwestern British Columbia is characterized by Mo–Cu porphyry, skarn, and carbonate replacement mineralization (“Laverdiere”, “Sulphide City”, and “Jackie” occurrences). This ore deposit system is hosted in the polymetamorphic Florence Range and Boundary Ranges metamorphic suites and felsic intrusive rocks. In this contribution, we combine detailed field mapping and igneous petrography with U–Pb zircon and titanite petrochronology to elucidate the magmatic history of these mineralized systems. Results indicate two distinct periods of magmatic and mineralizing activity at ca. 103–102 Ma and ca. 60–56 Ma and reflect the potential longevity and overprinting nature of mineralization related to the Coast Plutonic Complex in this region. Trace element signatures from analyzed zircons are similar to those from porphyry indicator zircons in large Andean porphyry deposits. Magmatic events are compared to similar porphyry systems occurring in northwestern British Columbia and southern Yukon within the Dawson Range batholith, and Ruby Range and Sloko-Hyder intrusive suites. Therefore, in this region, new age constraints illustrate the prospectivity of the Atlin Lake area and link the deposits at the Blue Property to a broader trend of mid-Cretaceous and Paleocene–Eocene porphyry-style mineralization.

The Canadian Spatial Reference System (CSRS) defines latitude, longitude, and heights in Canada, providing the foundation for all types of geospatial data.On a dynamic earth, these standards require constant monitoring and updating to keep pace with evolving technologies and geospatial data accuracy requirements.Currently, the federally adopted coordinate reference system is the North American Datum of 1983 of the CSRS (NAD83(CSRS)).