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.

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.

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.

This talk was presented November 22, 2022, at the Yukon Geoscience Forum.

In collaboration with the Yukon Geological Survey, Innovate Geothermal Ltd. performed a multi-component geoscientific investigation in southwestern Yukon to initiate the search for subsurface geothermal energy resources that could be used for direct use applications and, possibly, the generation of electricity. The study area for this project is located near the community of Burwash Landing and straddles the eastern Denali fault zone. The aim of this project is to analyze and interpret a variety of pre-existing and newly-acquired geological and geophysical data sets to identify favourable subsurface targets for a shallow, exploratory geothermal drilling program that could take place in the future. The geoscience work accomplished here includes both 2D map interpretation as well as construction of a 3D geologic model that was tested by geophysical inversion modelling of gravity and magnetic survey data. In addition, a literature review was conducted to identify analogous geothermal structural environments located in similar crustal-scale transform fault zones for comparison with geothermal systems that may be present in the vicinity of the Denali fault. Importantly, geophysical data from this study discovered a right-step in the Denali fault that has the appropriate orientation to form a small pull-apart zone in the Earth’s crust within the project area south of Duke River. Such crustal extension may generate fractures and permeability in rocks in the subsurface. Subsurface permeability in geothermal systems provides the pathway for hot geothermal fluids to ascend to drillable depths. This study has identified seven drilling targets, all located in the vicinity of the previously mentioned right-step in the Denali fault. The 3D geologic model generated for this study was utilized to help understand the lithologic domains and structures likely to be encountered by the proposed exploratory boreholes. The distribution of temperature in the subsurface, however, remains a significant unknown. Regional-scale, Curie point depth estimates suggest an average geothermal gradient of ~40°C/km near the eastern Denali fault, but drilling is required to measure actual subsurface temperatures. Based upon the encouraging results of this study, it is recommended that at least two of the seven targets are drilled to depths of 500–1000 m to obtain data on subsurface temperatures, fluids and geology.

In collaboration with the Yukon Geological Survey, Teslin Tlingit Council, and other project partners, Innovate Geothermal Ltd. performed an analysis of geoscience data in south-central 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 Yukon communities. The study area for this project is located near the Village of Teslin and straddles the Teslin fault zone. The main aim of this project is to analyze and interpret a variety of pre-existing and newly acquired geologic and geophysical data sets 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 and magnetic survey data. In the Teslin study area, the distribution of temperature in the subsurface remains a significant unknown; however, limited evidence suggests subsurface temperatures are modestly above average. Specifically, regional-scale, Curie point depth estimates suggest the geothermal gradient in the area is ~45 °C/km. Drilling is required to measure actual subsurface temperature gradients in the vicinity of Teslin. Furthermore, subsurface permeability does appear possible in the study area. Analysis of the geoscience data shows evidence for a complex structural environment that appears favourable for subsurface fracture permeability in the Teslin fault zone area. In addition, geologic mapping and geophysical modelling suggests that large portions of the Teslin study area are underlain by quartzite and volcanic bedrock. Both rock types have a favourable potential for maintaining open fractures. Many unknowns regarding the temperature and permeability of the subsurface still exist in the Teslin study area. The location of a 500 m deep scientific research well is proposed to help answer many of the remaining questions.

Initiated by the Northwest Territories Geoscience Office, the project Regional Geoscience Studies and Petroleum Potential, Peel Plateau and Plain, Northwest Territories and Yukon (2005 to 2009) involved partners from the Yukon Geological Survey, Geological Suvey of Canada, as well as universities and industry. The research team coupled field-based studies with subsurface analytical techniques to evaluate the study area's hydrocarbon potential. Over 70 interim publications have been produced. This volume compiles chapters devoted to several stratigraphic petroleum plays, along with structural and petroleum systems elements and a digital geodatabase (or atlas) of spatially based data collected during the course of the project . The result is a comprehensive body of geoscience work for Peel area which will be useful too in oil and gas exploration and for regional land use and business planning endeavours.

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Mining is expected to remain as Yukon's most important industry during the next 5-10 years. The future prosperity of the mining industry in Yukon depends on the discovery of new mineral deposits. These new discoveries will depend on up to date geoscientific research: geological mapping, geochemical and geophysical surveys, and mineral deposit studies. Government and First Nations also need the results of this research to evaluate mineral potential and assist with land use planning and environmental impact assessments. With this in mind, the Geological Survey of Canada, Northern Affairs Program (DIAND), Government of Yukon and the Yukon Chamber of Mines collaborated on a 2-day workshop in April, 1995, to identify and prioritize Yukon's Geoscience requirements for the next 5 to 10 years. This document summarizes the results of the workshop. It represents a consensus between the four sponsoring agencies, based on input from 34 geoscientists currently working in Yukon, and will be used in planning geoscientific research to ensure that priorities are met and that maximum value is obtained from available funding.

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.