In collaboration with the Yukon Geological Survey, the Geological Survey of Canada, and other project partners, Innovate Geothermal Ltd. performed an analysis of geoscience data in southwestern Yukon as part of an effort to better understand the potential for geothermal energy resources that, if present, could be utilized to help reduce fossil fuel use. The study area for this project is located in the vicinity of the Village of Haines Junction (Dakwäkäda) and lies between the Denali and Shakwak fault zones. The main aim of this project is to analyze and interpret a variety of pre-existing and newly acquired geological and geophysical datasets to evaluate where geothermal reservoirs may be present within the study area. A secondary aim is to propose favourable drilling locations, if warranted, for exploratory wells to collect information on subsurface temperature and permeability. The geoscience work accomplished here includes both 2D map interpretation as well as construction of a 3D geologic model that was guided by geophysical inversion modelling of gravity, magnetic and audio-magnetotelluric survey data. At a regional scale, multiple lines of evidence suggest that subsurface temperatures are above the crustal average. More importantly, a municipal water well drilled in 2002 in the Village of Haines Junction produce warm (~20 °C) water from a depth of ~350 m. This water well proves that at least one permeable sediment-hosted geothermal aquifer is present under Haines Junction. Additional geothermal aquifers within the pile of young sediment that sits atop the bedrock are likely present. However, due to a lack of deep drilling in the area, the exact location, temperature, thickness and permeability of such aquifers remains unknown. In this study, a depth-to-bedrock model has been generated to aid with the identification of favourable target areas for exploratory drilling of geothermal wells. The four areas where the top-of-bedrock is deepest have estimated depths in the range 650 to 1225 m below ground surface. Temperature data from two wells in the Haines Junction area suggests the temperature gradient is ~60 °C/km. Thus, geothermal aquifers located near the top-of-bedrock in the four areas identified could have temperatures in the range of 39–74 °C. Production of geothermal fluids from these areas requires permeability in the sediments that sit above the bedrock. Deeper drilling is needed to measure actual subsurface temperatures beneath the village and to identify permeable intervals. Geologic structures and faults that may control permeability in the bedrock remain poorly constrained.

As part of the Canadian government’s commitment to establishing clean energy in the North, the Yukon Geological Survey is collecting subsurface temperature data near communities in the southern part of the territory. The research is a collaborative effort among federal and territorial geoscientists, universities, First Nation governments, and geothermal consultants. A major goal of the project is to determine whether ground temperatures warrant further geothermal exploration in the territory. The study also presents an opportunity for Yukon Geological Survey to educate the public about geothermal energy. This paper summarizes the methods and results of the drilling of two ~500 m geothermal temperature gradient wells. The first was drilled in the fall of 2017 in the Whitehorse area, near Takhini Hot Springs, where a surface water seep measures 46°C. The second well was drilled in winter 2018 in the Tintina fault system, near Ross River. Results to date suggest warm fluids and possible permeable rocks in the Takhini well between 450 and 500 m from surface, and a higher than average geothermal gradient of ~31°C/km in the Tintina Trench near Ross River. The results do not indicate temperatures for power generation at economic depths, however, they are encouraging enough to warrant further geothermal studies in southern Yukon.

Summer 2017 fieldwork in Yukon’s lower Paleozoic shale basins (Selwyn basin and Richardson trough) involved participants from government geological surveys (Yukon Geological Survey, Geological Survey of Canada) and several universities (Queen’s, McGill, St. Francis Xavier, Stanford and Dartmouth College). Research interests include: 1) shale chemostratigraphy and biostratigraphy, and pyrite trace element geochemistry to characterize shale units and assess lower Paleozoic paleoenvironmental conditions and depositional controls; and 2) an assessment of hyper-enriched black shales, specifically the colloquial ‘Nick’ or ‘Ni-Mo’ mineralized Ni-Zn-Mo-PGE deposit, in order to develop internally consistent genetic and exploration models for these types of deposits. This paper describes individual research projects underway and summarizes fieldwork in summer 2017.

A regional till geochemistry project was completed in conjunction with bedrock mapping across rocks of Yukon-Tanana Terrane and North American affinity in central Yukon. The high mineral potential of the area is based on recent discoveries in the Finlayson Lake area to the southeast, an area thought to juxtapose the Glenlyon area prior to displacement on the Tintina Fault. The study area lies at the limit of the Late Wisconsinan McConnell glaciation. Ice flow was largely directed by topography. Soil profiles reveal a veneer of White River ash and loess over most till deposits. Geochemical results from 285 till samples highlight new anomalies in gold, gold/arsenic (intrusive- and fault-related), copper (veins), copper/nickel (ultramafic rocks) and zinc (sedimentary-exhalative (SEDEX) and epithermal). An orientation survey was completed at the Clear Lake SEDEX deposit to evaluate the extent of glacial dispersion down-ice from mineralization.

This report was written and prepared by the Canadian Geothermal Energy Association. It was developed with support from the Canadian Northern Economic Development Agency, Yukon Energy, and the Government of Yukon's Department of Energy, Mines, and Resources, including the Yukon Geological Survey and the Energy Solutions Center.

The southwestern Yukon Coast Belt mapping project is a joint Yukon Geological Survey/Geological Survey of Canada initiative operated under Natural Resources Canada’s GEM (Geomapping for Energy and Minerals) program. This project is aimed at investigating the geological relationships and mineral potential of the Kluane Schist, the Ruby Range batholith and the Yukon-Tanana terrane in southwestern Yukon. Bedrock mapping at 1:50 000-scale followed a 400 m line-spaced aeromagnetic survey flown in the winter of 2010. Preliminary results indicate the presence of a northeast-dipping structural stack through an ~40 km-thick crustal section, whereby the Kluane Schist occupies the lowest structural level and the Yukon-Tanana terrane the highest. The Ruby Range batholith intruded along the contact between the Kluane Schist and the Yukon-Tanana terrane, and was emplaced late in the deformation history. An orthogneiss/paragneiss unit of unknown tectonic affinity was mapped structurally between the Ruby Range and the Kluane Schist. Detrital zircon analyses from two samples of Kluane Schist indicate that the onset of deposition for this metasedimentary sequence occurred after ca. 94 Ma. Two significant metamorphic events, dated at 82 and 70 Ma, affected the Kluane Schist. This indicates that original structural juxtaposition between the Kluane Schist and the Yukon-Tanana terrane pre-dated intrusion of the Ruby Range batholith. Mineral potential in the Coast Belt area is significant and includes porphyry Cu-Mo-Au, epithermal Au-Ag and orogenic Au occurrences. The upper level of the Ruby Range batholith is most prospective for porphyry and epithermal mineralization, while the Kluane Schist is most prospective for orogenic Au mineralization.

In collaboration with the Yukon Geological Survey, Liard First Nation and other project partners, Innovate Geothermal Ltd. performed an analysis of geoscience data in southeastern Yukon as part of an effort to better understand the potential for geothermal energy resources that, if present, could be utilized to help reduce fossil fuel use in off-grid communities. The study area for this project is located near the Town of Watson Lake and straddles the crustal-scale Tintina fault zone. The main aim of this project is to analyze and interpret a variety of pre-existing and newly-acquired geological and geophysical datasets to evaluate whether geothermal reservoirs may be present within the study area. A secondary aim is to propose favourable drilling locations, if warranted, for exploratory wells to collect information on subsurface temperature and permeability. The geoscience work accomplished here includes both 2D map interpretation as well as construction of a 3D geologic model that was guided by geophysical inversion modelling of gravity, magnetic and magnetotelluric survey data. In the study area, the distribution of temperature in the subsurface remains a significant unknown; however, limited evidence suggests subsurface temperatures are modest. Regional-scale, Curie point depth estimates suggest an average geothermal gradient of only ~31°C/km. In contrast, two oil and gas exploration wells from the 1960s located 15–35 km outside the study area give a geothermal gradient range of ~38–50°C/km. Drilling is required to measure actual subsurface temperature gradients in the vicinity of Watson Lake. Evidence for substantial subsurface permeability is generally lacking in the study area. Analysis of the geoscience data did not reveal any specific locations along the Tintina fault that suggest a structural environment favourable for subsurface fracture permeability. Furthermore, the Tintina fault presents little evidence of active tectonism. Active tectonism helps maintain open fractures in the fault zone which could facilitate deep circulation of fluids to form a natural geothermal system. A lack of active tectonism could limit permeability in the fault zone. In addition, geophysical modelling suggests that large portions of the Watson Lake study area are likely underlain by shale-rich bedrock. This type of rock has very low permeability and is not favourable for maintaining open fractures. The only evidence for subsurface permeability found in this study is sand layers in the Cenozoic sedimentary rock of the Tintina trough. These sand layers could be permeable but are interbedded with low permeability layers such as silt and clay; the thickness and lateral extent of the sand layers is unknown. The 3D geologic model developed in this study suggests that the Cenozoic sedimentary rock of the Tintina trough is limited to less than ~1 km thick. This implies that fluids residing in sand layers in this rock unit would have a maximum temperature of between ~38 and 50°C. Geothermal fluids at these temperatures could potentially be utilized to help heat buildings in the community of Upper Liard. Many unknowns regarding the temperature and permeability of the subsurface still exist in the Watson Lake study area. The location of a 1 km deep scientific research well is proposed to help answer many of the remaining questions. However, considering the lack of evidence for bedrock permeability in the study area, other approaches to utilizing the Earth’s heat, such as Borehole Thermal Energy Storage (BTES) systems, could be considered to help the community of Watson Lake reduce dependence on fossil fuels for residential heating.

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Geoscience, which is the study of Earth systems, is complex and highly dynamic. It examines the interactions between the lithosphere, hydrosphere, biosphere and atmosphere – all of which are critical to sustaining our planet (AGI, 2012). The Yukon Geological Survey’s mandate is to provide objective geological information to Yukon government, Yukon First Nations and the general public. This information underpins geoscience-related policy and investment decisions in the territory, and adds value to Yukon’s geoscience knowledge base. With a staff of more than 15 geoscientists, the Yukon Geological Survey (YGS) conducts a wide variety activities from traditional bedrock and surficial mapping, to focused studies such as community hazards mapping (e.g., monitoring landslides and thawing permafrost), and mineral assessments, among others. As a government organization, it is our duty to not only engage with First Nations and other governments, but to also educate all citizens of the Yukon about the importance of geoscience in order to help society find and manage our natural resources for the present and future (Geoscientists Canada, 2018). YGS recognizes the importance of having a geoscientist on staff who is dedicated to outreach and education. Communicating geoscience effectively, and educating Yukoners on how Earth systems work will help them to make informed judgements that affect our territory, as well as our planet (AGI, 2011). Despite the ongoing pandemic, YGS remained very active in public outreach and education; this paper provides a summary of activities for 2021.

The Yukon Geological Survey (YGS) includes a staff of approximately 20 geoscientists that conduct a wide variety of studies, including traditional bedrock and surficial mapping, community hazards mapping (e.g., monitoring landslides and thawing permafrost), mineral assessments, metallogeny and geothermal research. The role of geoscientists is to provide the knowledge required to meet society’s demand for natural resources, environmental sustainability, and improved resiliency against geohazards (American Geosciences Institute, 2012). The mandate of YGS is to provide objective, geoscience-related information to government, Yukon First Nations, and the public. Our research helps inform geoscience-related policy and investment decisions in Yukon, as well as support the land-use planning process. As a public government organization, we must improve geoscience literacy through effective communication so that all citizens of the Yukon understand how Earth’s systems (lithosphere, biosphere, hydrosphere, and atmosphere) influence their everyday lives. Educating Yukoners will help them to make informed judgments that affect our territory and encourage public participation in policy making. Yukon Geological Survey recognizes the importance of having geoscientists on staff who are dedicated to outreach and education. As of September 2023, YGS has two full-time, permanent Outreach Geologist positions. This paper is a summary of YGS’ outreach and education activities over the last year