AndreaBozzo/ceres-open-data-index huggingface dataset:
Yukon Exploration and Geology 2023

The annual Yukon Exploration and Geology (YEG) volumes—YEG Overview and YEG Technical Papers—are the main publications of the Yukon Geological Survey (YGS; Energy, Mines and Resources, Government of Yukon). Individual YEG technical papers, with colour images, are available in digital format only. The YEG Overview is available in digital format and in a limited colour print run. All YGS publications can be downloaded from our website, https://data.geology.gov.yk.ca/.

The Yukon Exploration and Geology 2023 volumes contain up-to-date information on mining and mineral exploration activity, studies by industry and results of recent geological field studies. Information in this volume comes from prospectors, exploration and government geologists, mining companies and students, all of whom are willing to contribute to public geoscience for the benefit of the scientific community, the public and the mineral industry of the Yukon. Their work is appreciated.

Organization: Government of Yukon | Gouvernement du Yukon
Magmatic-hydrothermal deposits in central Yukon: Variations on a theme

This field trip guidebook was prepared for the 100th Anniversary Meeting of the Society of Economic Geologists originally planned to be held in Whistler, British Columbia, September 15–18, 2020. The meeting was postponed because of the global COVID-19 pandemic and was rescheduled to September 14–17, 2021, but the field trips were canceled due to travel uncertainty at the time. Victoria Gold Corp. (Eagle mine), Alexco Resource Corp. (Keno Hill district), Pembridge Resources (Minto mine), Copper North Mining Corp. (Carmacks Copper deposit) and Triumph Gold Corp. (Mount Freegold district) generously agreed to host the field trip and enabled their geologists to contribute to this guidebook. Anyone wanting to follow this guidebook is advised to contact the companies regarding access.

Organization: Government of Yukon | Gouvernement du Yukon
Early Pleistocene glaciation and implications for placer gold deposits in Back Creek, Mount Nansen area, Yukon

Yukon has over a century of placer mining history, predominately in unglaciated regions. However, as these targets are exploited, focus turns to more complex landscapes where glaciation has buried, eroded and incorporated placer gold. This study examines how Early Pleistocene glaciation in the Mount Nansen area, central Yukon, has affected placer gold deposits. Detailed stratigraphic analysis and sample collection has focused on Back Creek, where placer mining has exposed a 22 m section with several gold bearing units. In the section, sediment from two glacial advances cap sporadically preserved pre-glacial gravel. The section is variably dissected by younger placer gold bearing fluvial gravel with enrichment related to intersection of inter-glacial or pre-glacial placer gold deposits. Analysis at Back Creek reveals the potential for deeply buried placer gold deposits in other glaciated regions of Yukon.

Organization: Government of Yukon | Gouvernement du Yukon
Assessment of low permeability cover as infiltration and oxygen barrier to reduce acid generation in mine tailing at the Arctic Gold and Silver Mine Site, Carcross, Yukon

The production of acid rock drainage (ARD) from mine tailings is a significant environmental concern at various abandoned mine sites in Yukon. Leachate with low pH and high dissolved metals concentrations deriving from mine tailings impoundment areas can negatively impact various groundwater and surface water resources.

The presence of both oxygen and water is required for ARD to develop. Therefore, the reduction of the oxygen and water sources from the mine tailings will limit ARD production. This is the basis of reclamation of the Arctic Gold and Silver (AGS) Tailings Site near Carcross, Yukon using a lowpermeability tailings cover which acts as an oxygen and water infiltration barrier. ARD processes have resulted in a significant contamination of the groundwater beneath the tailings impoundment at the AGS site with multiple dissolved metals showing elevated concentrations.

The use of a low permeability cover to reduce ARD such as that used at the AGS site is one of the first such reclamation applications in Yukon. EBA Engineering Consultants Ltd. and partners initiated a performance assessment of the low permeability cover system in the fall of 2000 and continued the monitoring in 2001 as part of Mining Environment Research Group (MERG) funded studies. The results of these assessments suggested that the low-permeability cover functions as an oxygen and infiltration barrier; however, the limited data and short period of monitoring precluded any prediction of the long-term performance of the tailings cover. Further monitoring was recommended.

Organization: Government of Yukon | Gouvernement du Yukon
Summary of DGGS investigations at Livengood, Alaska: Geology, mineral potential, and regional correlations with east-central Yukon

The results of the DGGS investigation at Livengood, Alaska include bedrock geologic maps, a surficial geologic map, a detailed prospect examination and analyses of about 2000 stream-sediment, pan-concentrate, and rock samples. The geology and mineral potential of the Livengood area, as well as regional correlations with east-central Yukon are summarized in this report.

Organization: Government of Yukon | Gouvernement du Yukon
Interlayered sedimentary-volcanic sequence, Mt. Skukum volcanic complex

The Eocene Skukum volcanic complex, 60 km south-southwest of Whitehorse, is elliptical in plan, covers an area of about 140 km², and unconformably overlies Cretaceous granitic rocks and Precambrian metasedimentary rocks. The complex is fault-bounded and in places has been intruded by felsic dykes and stocks.

A major north-trending fault divides the area into two parts: a western part which includes a lower interlayered sedimentary-volcanic sequence and an upper unit, approximately 500 m thick, characterized by andesite lava flows, pyroclastic flows and sedimentary units; and an eastern part which comprises about 800 m of altered felsic pyroclastic flows and brecciated, flow layered and spherulitic felsic lava flows.

Study of the interlayered sedimentary-volcanic formation provides a control on the paleotopography of the Skukum area, and the depositional environment and provenance of the formation..

Organization: Government of Yukon | Gouvernement du Yukon
Case studies of high resolution resistivity/IP surveying over known mineral deposits: Yukon, Canada

High resolution resistivity/IP (HRRIP) surveys were carried out over nine mineral deposits within Yukon. The objectives of this study were 1) to investigate whether HRRIP surveys could map mineralization and structure associated with known deposits, and 2) to determine which arrays, if any, were the most diagnostic for a given deposit type. The study included a copper porphyry deposit, a lead-zinc-silver vein deposit, and several different styles of gold mineralization/deposits. The location of the HRRIP line(s) were chosen based on the known mineralization and geology of the deposit. On average 3 different arrays were carried out along each line. Variations of dipole-dipole, inverse Schlumberger and pole-dipole arrays, as well as an array developed by Advanced Geosciences Inc. of Austin, Texas were used. Two-dimensional inversions of each array for each line were carried out to produce 2D resistivity and IP cross sections. These sections provided the fundamental information for the study.

The deposits used in this report are Brewery Creek, Dublin Gulch, Flame and Moth, Klaza, Charlotte, Coffee, QV, Golden Saddle, and Williams South.

Organization: Government of Yukon | Gouvernement du Yukon
Yukon Exploration and Geology Overview 2023

Yukon Exploration and Geology (YEG) papers and the Yukon Exploration and Geology Overview are two of the main publications of the Yukon Geological Survey (YGS; Energy, Mines and Resources, Government of Yukon). Individual YEG papers, with colour images, are available in digital format only. The YEG Overview is available in digital format and in a limited colour print run. All YGS publications can be downloaded from our website, https://data.geology.gov.yk.ca/.

Yukon Exploration and Geology 2023 contains up-to-date information on mining and mineral exploration activity, studies by industry and results of recent geological field studies. Information in this volume comes from prospectors, exploration and government geologists, mining companies and students, all of whom are willing to contribute to public geoscience for the benefit of the scientific community, the public and the mineral industry of the Yukon. Their work is appreciated.

Organization: Government of Yukon | Gouvernement du Yukon
Geology and mineral deposits of the Mount Nansen camp, Yukon

The Mount Nansen camp hosts approximately 30 mineral occurrences of epithermal and porphyry origin. The largest occurrence is the Brown-McDade with approximately 600 000 tonnes of drill-indicated reserves at 6.1 g/t Au and 55.5 g/t Ag. The majority of the northwest-striking, steeply dipping epithermal quartz/sulphide veins are found within a 12 km long by 3 km wide northwest-trending corridor called the Nansen trend. The precious-metal-bearing veins occur in all lithologies within the Nansen trend and contain (in order of decreasing abundance) pyrite, arsenopyrite, galena, sphalerite, chalcopyrite, stibnite and tetrahedrite. Two types of epithermal veins are recognized: an early “cherty” quartz-sulphide vein with fine-grained pyrite and arsenopyrite; and a later coarse-grained quartz-sulphide vein with pyrite, galena and sphalerite and higher precious metal values. Within the trend is the Mount Nansen porphyry complex which hosts two cores of potassic alteration. The character of mineral occurrences varies with increasing distance away from these Central Porphyry Zone and are here recognized as the Peripheral Porphyry, Transitional and Epithermal zones. Together, they comprise a porphyry-to-epithermal transition. Placer mining is predominant on creeks draining from the porphyry complex, implying a porphyry source for the placer gold.

Organization: Government of Yukon | Gouvernement du Yukon
Preliminary Metallogenic Maps of Yukon

Preliminary metallogenic maps for Yukon were produced by combining information from the newly released digital geology map of Yukon (Gordey and Makepeace, 1999) and the Yukon Minfile (1997) database. The maps are presented as a series of eleven time slices divided as follows: Early and Middle Proterozoic, Late Proterozoic, Late Proterozoic to Early Cambrian, Cambrian to Early Devonian, Devonian to Mississippian, Pennsylvanian to Permian, Triassic to Jurassic, Early and mid-Cretaceous, Late Cretaceous, and Tertiary. Each map shows the geology of the particular time slice and the mineral occurrences of that age. The mineral occurrences have been classified according to mineralization type and main commodity/commodities.

The maps for the Mesozoic and Tertiary have been subdivided into types of mineral occurrences. For example, there are five maps for the Early to mid-Cretaceous, the first of which shows all mineral occurrences; the remaining four maps show porphyry, skarn, vein, and carbonate-hosted occurrences, respectively. In addition, coal occurrences and deposits, regardless of age, are shown on the last map of the series entitled "coal-bearing strata".

The metallogenic maps show the distribution of metals and reveal which rock units have known mineral potential. They highlight the fact that most of the Yukon remains an exploration frontier with significant potential. This is illustrated by the recent discovery of volcanic-associated massive sulphide (VMS) deposits in the Finlayson Lake district and significant new discoveries of intrusion-related gold systems (IRGS) mineralization in the "Tombstone Gold Belt", and also, the recent discovery of emeralds in rocks not previously known to have gemstone potential. In addition to hard rock mineralization, Yukon also contains numerous placer gold deposits.

Organization: Government of Yukon | Gouvernement du Yukon
Stratigraphic, structural, and tectonic setting of an upper Devonian-Mississippian volcanic sedimentary sequence and associated base metal deposits in the Pelly Mountains, southeastern Yukon Territory

The central Pelly Mountains in southeastern Yukon Territory consist of imbricate thrust sheets, which have undergone syn and post-thrusting deformation and metamorphism. The local geology is further complicated by intrusion of Upper Cretaceous batholiths, and by strike-slip faulting related to the Tintina Fault, a major northwest-trending transcurrent fault of uppermost Cretaceous or early Tertiary age. This faulting disrupts the northeast edge of the study area. Upper Devonian and Mississippian strata are present in at least two of the thrust sheets, but the Mississippian volcanic rocks occur in only one of them. The volcanic rocks consist of volcaniclastic material with minor interbedded flows, and were deposited in a submarine environment. Several coeval and cogenetic syenite and trachyte domes and small stocks are the remains of vent areas. Although the volcanic rocks are all highly altered and show evidence of widespread chemical mobility, trace element data indicate that the rocks are meta-luminous trachytes, most closely resembling peralkaline volcanics generated in extensional environments. This suggestion of a predominantly extensional tectonic setting in mid-Mississippian time in the Pelly Mountains is consistent with recent tectonic syntheses for the area. Stratabound and stratiform massive base metal sulphide deposits that occur within the Mississippian volcanic sequence are similar in many respects to the Kuroko-type volcanogenic massive sulphide deposits of Japan. The Pelly Mountains deposits, however, are among the first known occurrences in the world of Kuroko-type mineralization in a rift environment.

A copy of this thesis is available at the EMR library – QE195 M67 1979.
This thesis is available online at http://hdl.handle.net/2429/22257.

Organization: Government of Yukon | Gouvernement du Yukon
Yukon Exploration and Geology 1992

Yukon Exploration and Geology 1992 consists of three parts: Part A is a comprehensive overview of mining and exploration activity in the Yukon; Part B summarizes the activities of the Exploration and Geological Services Division (EGSD) of the Northern Affairs Program; Yukon Region and the activities of the Canada/Yukon Geoscience Office; and Part C which documents significant new geoscientific information gathered by EGSD geologists, Canada/Yukon Geoscience Office geologists and affiliated geologists such as students and contractors. Part C is a compilation of geological research papers based on geological fieldwork; these papers are searchable as separate individual metadata records.

Organization: Government of Yukon | Gouvernement du Yukon
Geology of the Main Zone at Mt. Skukum, Wheaton River area, southern Yukon

Gold mineralization at the Mt. Skukum deposit occurs in nearly vertical quartz-carbonate veins which crosscut flat-lying andesites with a NNE trend. The mineralized veins represent the second stage of a two stage hydrothermal system, the first of which resulted in emplacement of thin chalcedonic veinlets. These two stages of veins are probably indicative of an evolving hydrothermal fluid rather than being representative of two separate events.

Vein emplacement is one of the latest of a series of events which began with volcanism, producing felsic and andesitic volcanic rocks which overlie basement in this area. Subsequent periods of tectonism produced large faults along which rhyolitic dykes were emplaced. Continued tectonism resulted in reactivation of old faults along which andesitic and dacitic dykes were injected, crosscutting rhyolite dykes in many cases. As volcanic activity waned, the faults remained active, leaving zones of high permeability which acted as conduits for the still active hydrothermal circulation.

Veins appear to have been emplaced at low temperature in a circulating hydrothermal system driven by a heat source at depth associated with dykes present in the area. Circulating hydrothermal fluids may have leached gold from the surrounding andesitic volcanics during propylitization. Permeability may have been controlled by faulting, brecciated flow tops and bottoms, and lapilli tuff horizons. Gold was precipitated in highly permeable conduits, such as the Main Fault Zone and breccia bodies.

Organization: Government of Yukon | Gouvernement du Yukon
Geology of the northern Whitehorse trough, Yukon (105E/12, 13 and parts of 11 and 14; 105L/4 and parts of 3 and 5; parts of 115H/9 and 16; 115I/1 and part of 8)

Map presents an interpretation of the bedrock geology of the northern Whitehorse trough as extrapolated from field observations and a reflection seismic survey.

Organization: Government of Yukon | Gouvernement du Yukon
Arsenic, chromium, and selenium speciation in Selwyn Basin, Yukon

At present, little metal speciation information exists for most parts of the Yukon. The current database of knowledge is largely based on research from southern stream environments which tend to be warmer than Yukon streams. This presents a challenge for regulators and practitioners interpreting data from northern systems using guidance that is developed and defined by southern baseline data and effects. This study was designed using a preliminary approach to assist in filling the current information gap. The Selwyn Basin in the Yukon has natural elevated concentrations of metals including arsenic, mercury and selenium (EDI 2008, Gartner Lee 2007). Water quality studies that have been conducted within the Selwyn Basin have not considered the importance of metal speciation and changes in mobility and exposure to aquatic organisms inhabiting lotic watercourses likely impacted by both naturally elevated and anthropogenic (mining related) metal input sources. The objective of this project was to increase the understanding of metal speciation in relation to surface water and sediment metal concentrations within the Selwyn Basin at six discrete lotic watercourse sites over two seasons.

Organization: Government of Yukon | Gouvernement du Yukon
Quaternary history of McQuesten map area, central Yukon

Preliminary results from the Stewart River stratigraphy and surficial mapping suggest a minimum of four glaciations and two interglacial periods. Methods of stratigraphy, paleomagnetics, soil analysis, tephra chronology, and relative geomorphic preservation are employed to differentiate and describe Quaternary events. Glaciations, from oldest to youngest, are the pre-Reid (multiple early to mid Pleistocene glaciations), Reid (> 200 000 years), and McConnell (14 000 - 29 600 years). Interglacials are represented by organic deposits from Stirling Bend and Ash Bend, in addition to Wounded Moose and Diversion Creek paleosols preserved on pre-Reid and Reid surfaces.

During their maximum extent, pre-Reid ice sheets inundated the study area leaving isolated nunataks on Klondike Plateau and the northern part of Stewart Plateau near Syenite Range. North trending intervalley channels on Stewart Plateau represent confined ice flow in Stewart and McQuesten River valleys from ice obstructions in Tintina Trench. Undifferentiated pre-Reid surficial materials are thick in the lowlands of Klondike Plateau and Tintina Trench, areas proximal to the terminus of multiple pre-Reid glaciations. Reid ice terminated at Reid Lakes in the Tintina Trench. The McConnell ice sheet impinged into the east boundary of the study area, terminating approximately 20 km northeast of Stewart Crossing.

Petrographic analysis of woody material from the oldest pre-Reid deposit at Stirling Bend (unit A), suggests a late Tertiary age. Paleomagnetic measurements from overlying loess (unit B) and glaciofluvial sediments (unit C) have undetermined polarity. Remaining pre-Reid glacial and interglacial units from Stirling Bend have normal polarities and represent deposits from either a subchron within the Matuyama reversed chron or early Bruhnes normal chron. Reid deposits underlie Sheep creek tephra at Ash Bend suggesting a minimum age of 200 000 years. McConnell deposits are late Wisconsin age.

The distribution of surficial materials, related to multiple glaciations, physiography, and fluvial order contrasts, may govern the distribution of placer occurrences in McQuesten map area. Placer deposits occur anomalously in areas around Klondike Plateau, coinciding with the terminus of pre-Reid glaciations, Further exploration in pre-Reid ice terminal environments may yield significant placers through a better understanding of sediment distribution and genesis.

Organization: Government of Yukon | Gouvernement du Yukon
Report of field work on the Upper Triassic reef complex of Lime Peak, Laberge Map Area, Yukon

Field study has shown that the Upper Triassic carbonates at Lime Peak are a series of framework reefs which have shed debris into a surrounding basin. The reefs are up to 150 m thick and are dominated by spongiomorphs, tabulozoans and sponges. They bear little resemblance to those previously described in the Triassic of North America.

Organization: Government of Yukon | Gouvernement du Yukon
Yukon hard rock mining, development and exploration overview 2020

Yukon mineral exploration activity was severely affected by the COVID-19 pandemic and associated travel restrictions early in the year. As the summer began, exploration and mining companies were able to adjust their operating procedures and develop plans to allow them to adapt to the new reality. Companies implemented measures such as limiting the number of persons in camps, hiring local Yukon-based employees and contractors, increasing work rotation times so that employees spent less time in self-isolation, arranging for hotels to be used for self-isolation centres, having self-isolation spaces and procedures in camps and limiting the number of non-project personnel on site. These measures were crucial in turning around what was looking like a bleak exploration season and allowing for some sense of normalcy.
An increase in precious and base metal prices in mid-summer provided a much-needed shot in the arm for junior exploration companies. Yukon Geological Survey (YGS) tracks mineral sector spending through press releases, SEDAR and correspondence with companies. Although spending projections were dire at the start of the field season, by year-end, exploration expenditures are expected to be between $70 and $80M (vs. $117M in 2019). Development expenditures for the year are expected to be $65M, down from $225M in 2019. The drop in development expenditures is primarily due to the completion of construction at Victoria Gold Corp.’s Eagle Gold mine. Year end metal production for 2020 is approximately $300M with production coming from Eagle Gold, Minto and the newly re-opened Keno Hill mines.

Organization: Government of Yukon | Gouvernement du Yukon
Structure of schist in the vicinity of the Klondike goldfield, Yukon.

This study describes the structural evolution of the Klondike Schist and the structural setting of mineralized mesothermal veins from which over 500 tonnes of placer gold has been derived. The Klondike Schist was emplaced as a series of thrust slices on top of a structural stack that includes at least three additional thrust slices. A distinctive set of mesoscopic structures, particularly a set of recumbent folds, formed during thrust emplacement. These folds have a general southeast trend, and deform thrust-emplaced ultramafic rocks. Underlying thrust panels contain folds that resemble these thrust-related structures, but have a consistent northeast trend. The Klondike Schist may have
been rotated about a vertical axis during the latter stages of thrusting along phacoidal cleavage zones. Extensional sites in post-thrust kink folds and faults host mesothermal gold veins. Hence, gold mineralization postdated thrust stacking. Normal faults offset mesothermal veins, and host late-stage hydrothermal alteration zones.

Organization: Government of Yukon | Gouvernement du Yukon