AndreaBozzo/ceres-open-data-index huggingface dataset:
Paleomagnetism and geobarometry of the Granite Mountain batholith, Yukon: Minimal geotectonic motion of the Yukon-Tanana Terrane relative to North America

Paleomagnetic and geobarometric results are reported here for the Early Jurassic Granite Mountain batholith, an ~600 km² granodiorite intrusion in the Yukon-Tanana Terrane. Paleomagnetic analyses of 331 specimens from 24 sites yield magnetite-borne characteristic remanent magnetization (ChRM) directions. Eight northerly and westerly sites display a mean direction A (D=337, I=69°; a 95 =7.6°, k=54). Another 11 sites appear to be lightning-struck, or exhibit unstable remanence, and 3 sites in a fault-bounded block to the southeast carry an anomalous northeast upwards ChRM direction B. Two sites in a Cretaceous andesite porphyry dyke and its contact zone give a westerly, steep-down ChRM direction, C. Aluminum-in-hornblende geobarometry at 10 sites defines emplacement depths of ~16 km in the north and west, and ~19 km in the southeast. The batholith has probably not been significantly tilted since its emplacement, but it may be subdivided into two separate intrusive phases or structural blocks that have experienced differential uplift. Ambient temperatures at 16-19 km were too high for magnetite to record an enduring remanence, so the observed ChRMs likely record uplift of the batholith through ~15 km depth, at 180-170 Ma. Both A and C ChRM directions are similar to those expected for Early Jurassic and Late Cretaceous reference poles, respectively, suggesting that the Yukon-Tanana Terrane is not far-traveled with respect to cratonic North America since Early Jurassic time.

Organization: Government of Yukon | Gouvernement du Yukon
Structure and alteration related to gold-silver veins at the Skukum Creek deposit, southern Yukon

A detailed evaluation of structure and alteration related to gold- and silver-rich, base metal-bearing veins was completed at the Skukum property as part of the 2002 mineral exploration program.
The structural setting is an east-trending sinistral strike-slip system bounded by the Berney Creek and Goddell faults to the south and north, respectively. The deposit comprises northeast-trending quartz-sulphide mineral shear veins that formed during syn-tectonic intrusion of rhyolite and andesite dykes related to the Eocene Mount Skukum caldera complex. A genetic relationship between mineralization and certain rhyolite dykes is indicated by patterns of alteration and mineralization. Dilational, northeast-trending structures interconnect and splay off the controlling faults, and host extensional quartz-sulphide mineral veins.
At Skukum Creek the main gold-silver-bearing minerals are electrum and freibergite, which precipitated with late galena-stibnite mineralization, whereas refractory gold in arsenopyrite is the main style at Goddell. A geological model is proposed that facilitates identification of prospective
structures within the property.

Organization: Government of Yukon | Gouvernement du Yukon
Preliminary geology north of Mount Mye, Anvil District (105K/6, 105K/7), central Yukon

The northeast Anvil area, 15 km north of Mount Mye (NTS 105K/6, 105K/7), is underlain by a conformable Cambrian-Devonian volcanic and sedimentary package with an aggregate thickness of greater than 1600 m. The lowest unit, with an exposed thickness of 120 m, consists of calcareous phyllites of the Cambrian-Ordovician Vangorda formation. Conformably overlying the phyllites is a >900-m-thick Ordovician-Silurian sequence of submarine basalt flows and volcaniclastic sedimentary rocks of the Menzie Creek formation. Volcaniclastic sediments are dominantly coarse, proximal, fragmental breccias with lesser conglomerates, sandstones, and siltstones. Carbonaceous shales with lesser siltstones, limestones, dolostones, and quartzites of the Ordovician-Devonian Road River Group (>450 m) are intercalated with and overlying the basalt flows.

The east margin of the map area is a depositional edge of basalt volcanism with only scattered thin flows occurring further to the east. This depositional edge is considered to be a north-trending, west-side-down, Ordovician-Silurian syndepositional, normal fault forming the east margin of a sedimentary sub-basin infilled with volcanic rocks. Hornfelsing on the east margin of the map area indicates a large, shallowly buried, northwest extension of the mid-Cretaceous Orchay Batholith.

Organization: Government of Yukon | Gouvernement du Yukon
Finlayson project: Geological evolution of Yukon-Tanana Terrane and its relationship to Campbell Range belt, northern Wolverine Lake map area, southeastern Yukon

Geological mapping in Wolverine Lake area has outlined new Yukon-Tanana Terrane stratigraphy, constrained the stratigraphic position of the Wolverine Lake volcanogenic massive sulphide (VMS) deposit, and clarified the relationship of Yukon-Tanana Terrane to the Campbell Range belt. Yukon-Tanana Terrane comprises two stratigraphic successions separated by an angular unconformity. Beneath the unconformity are polydeformed felsic and mafic meta-volcanic rocks, carbonaceous meta-clastic rocks, marble and granitic orthogneiss. The Kudz Ze Kayah VMS deposit occurs in felsic meta-volcanic rocks of this sequence. Yukon-Tanana Terrane rocks above the unconformity are deformed by only one phase of deformation and consist primarily of carbonaceous meta-clastic rocks and quartz- and feldspar-phyric felsic meta-volcanic rocks. The Wolverine VMS deposit occurs in this succession, associated with siliceous exhalite and baritic magnetite iron formation. Meta-basalt of the Campbell Range belt, included previously in Slide Mountain Terrane, overlies the upper succession of Yukon-Tanana Terrane with sharp contact. This contact has been observed at several localities and it appears depositional. There is no evidence that it is a terrane boundary fault.

Organization: Government of Yukon | Gouvernement du Yukon
Preliminary observations on stratigraphy and hydrocarbon potential of middle to Upper Cretaceous strata, Eagle Plain basin, northern Yukon.

The Eagle Plain basin, having proven hydrocarbon potential, is a relatively underexplored intermontane basin located in northern Yukon . Previous studies of the middle Albian-Cenomanian Parkin Formation and the Turonian Fishing Branch Formation are based on broad lithostratigraphic correlations. The primary goal of the study is to refine the sequence stratigraphic framework of the middle to Upper Cretaceous succession based on sedimentological observations. New findings from this study require subdivision of the stratigraphic nomenclature by defining new informal lithological members. Facies transitions, paleoflow indicators and isopach maps indicate overall westward deepening of the basin. Large-scale, sand-prone mass transport deposits observed in the upper part of the lower Parkin shale member in western Eagle Plain indicate the presence of shelf-to-basin floor relief of at least 100 m. Recognition of significant shelf-to-basin floor topography greatly increases the potential for hydrocarbon reservoirs (gas-dominated) in stratigraphic traps associated with the shelf edge.


Organization: Government of Yukon | Gouvernement du Yukon
Sluicing in the Yukon Territory - 1984

In the Yukon, the relatively low initial cost, high concentrating ratio, durability, high throughput, ease of use and acceptable recovery rates are reasons the sluice, in its many forms, has remained the favourite since the turn of the century.

The term "sluice box" is a broad generic term that encompasses just about any device that confines a slurry of water and gravel to a fixed, usually rectangular cross-section at a constant gradient.

Yukon placer miners still appear to regard the sluicebox as the most cost-effective method of treating placer gold deposits. Though simple to construct and operate, the behaviour of a sluice box is really quite complex. This is part of the reason that it has not been extensively researched.

The feed rate of water or gravel per foot of sluice width, riffle configuration and feed geometry of sluice boxes vary considerably throughout the Yukon. This great variety of operating practices seems far in excess of that required. In this respect, the Yukon is no different from the rest of the North American placer mining industry. The lack of consensus among placer miners indicates the need for a more fundamental understanding of the sluice box.

Organization: Government of Yukon | Gouvernement du Yukon
A transect through the accreted terranes of the nothern Canadian Cordillera: from Cassiar, British Columbia to Kluane Lake, Yukon.

This five-day geological excursion across the northern Canadian Cordillera of southern Yukon and northern B.C. will lead the participants from the parautochtonous edge of ancestral North America (Laurentia), near Cassiar, BC, through the Intermontane (peri-Laurentian) terranes and the oceanic Cache Creek Terrane (of Tethyan affinity), and end in the exotic Insular terranes (of Arctic affinity) by Kluane Lake, in southwestern Yukon. The trip will examine the internal and external relationships of terranes that were accreted to ancestral North America in Mesozoic time and discuss models of Cordilleran evolution. Although the field trip route offers limited opportunity to examine the mineral wealth of these terranes, metallogenetic highlights will be presented within their regional tectonic context along the way.

Organization: Government of Yukon | Gouvernement du Yukon
First vertical derivative of the magnetic field, McQuesten Aeromagnetic Survey, NTS 115J/16 and part of 115J/15, Yukon

Map of the first vertical derivative of the magnetic field derived from data acquired during an aeromagnetic survey carried out by Goldak Airborne Surveys from November 19, 2008 to February 19, 2009. The data were recorded using a split-beam cesium vapour magnetometer mounted in the tail boom of a Piper Navajo aircraft.

Organization: Government of Yukon | Gouvernement du Yukon
2002–03 Supplementary estimates no. 2

Supplementary estimates no. 2 for the Government of Yukon 2002–03 Budget. 
This document was prepared by the Department of Finance under the direction of Management Board for the 1st Session of the 31st Legislature, Yukon Legislative Assembly. October 2003, Whitehorse, Yukon.

Organization: Government of Yukon | Gouvernement du Yukon
Surficial geology, soils and permafrost of the northern Dawson Range.

New mineral discoveries in the Dawson Range have been heavily supported by soil geochemistry. The use of soil augers to penetrate through loess-rich units and into locally derived weathered bedrock has been important in the successful application of this technique. To assist the mineral exploration industry, we characterized the surficial geology, soils and permafrost of the northern Dawson Range. Mapping indicated that widespread loess is present in the study area and the thickest deposits are located in basins on the south side of the Dawson Range near the Donjek and White rivers. A mantle of weathered bedrock covers virtually the entire landscape. The texture of fluvial deposits is affected by stream order and base level changes along the Yukon River. By understanding the effects of slope, aspect, elevation and permafrost processes on surficial materials, a landscape model can be developed that will facilitate geochemical exploration and mineral development in the region.

Organization: Government of Yukon | Gouvernement du Yukon
Multisensor airborne geophysical survey, Stewart River area, 115N/1

Data were acquired during the second phase of an airborne geophysical survey (gamma ray spectrometer, magnetometer) carried out by Fugro. Funding was provided by Natural Resources Canada's Targeted Geoscience Initiative. The survey was completed between July 18 and September 28, 2001.

Organization: Government of Yukon | Gouvernement du Yukon
Seismic investigation of ice properties and bedrock topography at the confluence of two glaciers, Kaskawulsh Glacier, Yukon Territory, Canada

Seismic investigations were carried out at the confluence of the North and Central Arms of the Kaskawulsh Glacier, St. Elias Mts. Low velocities near the glacier surface are apparently due to melting, fracturing, and high porosity. It is concluded that velocity anisotropy is mainly caused by the foliation structure of alternating layers of clear and bubbly ice; it also occurs where surface ice has a strong fracture pattern. Greatest depth of ice in the Central Arm, 3,000 m wide, and in the combined glacier, 5,000 m wide, is about 1,000 m. The North Arm is less deep; both arms are roughly parabolic in cross section. The base of the ice is lower than the glacier terminus, but no bedrock depression was found at the confluence. It is concluded that only under especially favorable circumstances can seismic measurements be used practically to study crystallographic fabrics in glacier ice.

Organization: Government of Yukon | Gouvernement du Yukon
An Evaluation of the Gold Recovery of Placer Drills Using Radio Tracers

In the last five years, eroding gold prices, increasing production costs and the depletion of reserves have resulted in a dramatic increase in the use of drilling to evaluate placer deposits. Accurate sampling and deposit evaluation would enable planning for cost-effective mining and reclamation. However, sampling placer gravel accurately is an extremely difficult task due to the nugget effect (inclusion or loss of a single particle of gold) and any errors are compounded by the small size of the drill samples. Additional sampling errors result from contamination, splitting and fire assaying. More placer mine failures can be attributed directly to improper sampling and sample processing practices during property evaluation than to any other cause.

There is very little impartial, accurate information available to guide the selection of modern drills. Drillers and their equipment are often selected for their penetration rate or cost-per-foot rather than for sampling accuracy or gold recovery. A brief description of several types of drills including churn, auger, rotary tricone, reverse circulation, Becker hammer, down-the-hole hammer and Sonic drills is summarized in Section 6 from references.

Three solid auger drills and two types of reverse circulation (R/C) drills were evaluated under typical Yukon field conditions using radioactive placer gold as tracers (radiotracers). A frozen cylindrical core of compacted gravel containing four sizes (-10+14, -20+28, -35+48 and -65+100 mesh) of radiotracers was placed in 35 drill holes and the holes were redrilled. Hand-held scintillometers were used to track gold losses during drilling, sample recovery and sample processing. Radiotracers lost due to spillage and blow-by around the collar (top) of the hole, and those trapped in drilling equipment (carry-over) were easily located. The results of these tests are summarized Table 1.

There was no significant difference between the recovery of the four sizes of gold particles with any of the reverse circulation or auger drills tested. Observations and down-hole scintillometer records indicate that the radiotracers did not follow the bit down the hole and were either carried out of the hole or forced onto the sides of the hole at or above the depth at which the radiotracer core was positioned.

Organization: Government of Yukon | Gouvernement du Yukon
Bedrock geology of NTS 95C/5 (Pool Creek) and NTS 95D/8 map sheets, southeast Yukon

Map sheets 95C/5 and 95D/8 in southeast Yukon contain eight successions of sedimentary rocks ranging from Proterozoic to Paleocene in age. Early to middle Paleozoic starta are best preserved. Proterozoic strata have been tentativel correlated with Pinguicula Group, Mackenzie Mountains Supergroup and Windermere Supergroup. Newly defined Cambrian-Ordovician Crow Formation documents shallow water to suaerial siliciclastic sedimentary rocks related to a paleogeographic high.

Organization: Government of Yukon | Gouvernement du Yukon
Lower to Middle Jurassic stratigraphy, ammonoid fauna and sedimentary history of the Laberge Group in the Fish Lake syncline, northern Whitehorse Trough, Yukon, Canada

The Upper Triassic to Middle Jurassic Whitehorse Trough is a 500-km-long forearc basin developed on the eastern margin of the Stikine Terrane. Basin fill in the Fish Lake syncline consists of Early to Middle Jurassic strata of the Laberge Group. Re-examined fossil collections record all ammonite zones from the Upper Pliensbachian to lowest Bajocian (except for the recessive or volcanic Aalenian Stage), suggesting that the Laberge Group is a conformable sequence. Biostratigraphic dating of oldest conglomerates indicates that source area uplift occurred first in the north in the Early Pliensbachian, progressing southwards through the Late Pliensbachian. Periodic, basin-wide anoxia was prevalent during the Middle and Late Toarcian, indicated by abundant Bositra, a low-oxygen-tolerant bivalve. The final stage of basin-fill, Early Bajocian chert-pebble conglomerates, provides a maximum age constraint on the amalgamation of the Cache Creek and Stikine terranes.

Organization: Government of Yukon | Gouvernement du Yukon
Yukon Geological Survey: Planning for the future

The Yukon Geological Survey (YGS) had a busy year in 2019, welcoming seven new staff and initiating several new projects. In addition to its regular activities, the survey hosted a planning workshop with clients and stakeholders in April to identify gaps in Yukon’s geoscience knowledge base and engage participants in a discussion about their current and future information needs. The YGS holds these workshops every five years, and they are valuable for providing insights into research and exploration trends, generating ideas for new projects, and identifying opportunities for collaborative partnerships. As a backdrop for these discussions, participants were asked to consider how existing and emerging markets, climate change, societal needs and new technologies might influence how the YGS collects, manages and disseminates information.
This paper provides both a brief overview of 2019 program activities and a summary of what was heard at the April planning workshop. Workshop discussions covered a broad range of topics and included both specific project ideas as well as general themes. The YGS has already initiated some of the projects that were proposed in April. The paper is organized based on the thematic breakout sessions at the workshop; current activities underway under each of the themes are presented first, followed by a summary of the input heard at the workshop.

Organization: Government of Yukon | Gouvernement du Yukon
Geology Map of the Tiny Island Lake Map Area (105M/16)

Geological map (1:50,000 scale) of Tiny Island Lake map area, central Yukon (NTS 105M/16) including mineral occurrences, geological cross sections, structural relations, mesoscopic fabric data and descriptive notes on stratigraphy, intrusive rocks, structure, metamorphism and guide to mineral exploration.

Organization: Government of Yukon | Gouvernement du Yukon
Whitehorse Copper Mine Reclamation Review, Yukon Territory

Mining activity at the Whitehorse Copper Mine has resulted in a disturbed land area of approximately 800 acres. Within this area there are about 53 acres with active slope instability and subsidence associated with the mine and underground workings. The mine is located within the city limits of Whitehorse, about six miles from the city centre. Although the mine has been decommissioned to a level acceptable to the mine inspector, there is still some concern for public safety. In addition, the current decommissioning plan is expected to result in the permanent loss of useful land from within the city limits. This report presents an assessment of the site conditions and options for reclamation to address these concerns.

Organization: Government of Yukon | Gouvernement du Yukon
Geology of Spencer Creek (105B/1) and Daughney Lake (105B/2) Map Areas, Rancheria District, Southeastern Yukon

Twelve lithostratigraphic units, including ten autochthonous and two allochthonous units, are recognized, and most of these are divided into 27 subunits. They range from Cambrian to Quaternary in age and include a wide range of sedimentary, igneous and metamorphic rock types. Lower Cambrian siliciclastic and carbonate rocks of the Cassiar Batholith predominate.

Three phases of structures are identified. First phase structures include bedding and slaty cleavage, of which the latter is attributed to late stage diagenetic recrystallization. Second phase structures trend northwest and include crenulation cleavage and related folds and lineations. They are attributed to northeast-southwest compression resulting from accretion and obduction of allochthonous rocks during arc-continent collision in Late Jurassic-Early Cretaceous time. Third phase structures are approximately 90° to the second phase structures and trend northeast. They include joints and related folds and lineations and are attributed to dextral transcurrent movement on Tintina, Kechika and Cassiar faults.

Precious and base metal mineralization is found mostly within Paleozoic sedimentary rocks and Cretaceous plutonic rocks and forms predominantly veins and replacement lenses. The dominant sulphides include galena, sphalerite, pyrite and chalcopyrite. Arsenopyrite, freibergite, tetrahedrite, pyrrhotite, wolframite, cassiterite, stannite, fluorite and lepidolite are also present. Common gangue minerals include quartz, siderite and iron and manganese oxides. Mineralization appears to be structurally controlled by the northeast-southwest jointing and, to a lesser extent, lithologically controlled by limestone-phyllite contacts. It is attributed to hydrothermal solutions migrating along the joints and was probably deposited approximately 50 Ma ago. The most useful exploration guide to finding additional mineralization is iron and manganese gossans.

Organization: Government of Yukon | Gouvernement du Yukon
Historical notes

Few metals occur naturally. Gold and copper are the major exceptions. Prehistoric people likely found these elements as anomalous particles in stream beds. Although copper subsequently proved to be of some practical value for arrowheads, knives, etc., gold, being extremely soft, had only an ornamental value. It was, nevertheless, apparently highly prized, judging from its appearance in ancient graves and the fact that it was mined. Placer mining was well established by 3800 B.C. as shown by drawings on Egyptian monuments of that era. It seems that placer mining, which has been an industry for some six thousand years, shows no signs of dying out.

Organization: Government of Yukon | Gouvernement du Yukon