The Exposure area is underlain by Devonian to Permian marine sedimentary and volcanic rocks of the Stikine Assemblage which are overlain by marine sedimentary and volcanic rocks of the Upper Triassic Stuhini Group. Lower Jurassic rock of the Hazelton groups overly the Stuhini rock.
The volcanic and sedimentary sequences were intruded by the Tertiary-Cretaceous Coast Plutonic Complex. A wide variety of intrusive phases are present including granodiorite, quartz monzonite and diorite. Small satellitic plugs from the main batholith are important for localizing mineralization.
The predominant lithologies on the property consist of marine sediments, volcaniclastics and volcanic flows. The marine sediments consist of argillites, argillaceous siltstones and siltstone with some quartzite, greywacke and carbonates. These sediments are interbedded with contemporaneous marine volcanics ranging from rhyodacite to basalt in composition. Volcanic facies include crystal fragmental tuff, lithic tuff, breccias, agglomerate, flows and sills.
Low grade regional metamorphism has occurred within the marine sediments which contain abundant chlorite. Foliation is usually conformable with the bedding. Fault and shear zones trend 135 degrees and about 045 degrees with andesite and basalt dykes following the 045 degree structures and felsite dykes related to the 135 degree structures.
A quartz diorite mass intrudes the sediments and volcanics and is exposed in the southwestern part of the property. The intrusive is medium to coarse-grained and is comprised of sub to euhedral crystals. A satellite plug of this intrusion occurs on the ridge between Second and Third Basins, immediately north of the main pluton.
The Exposure showing is located immediately north of the quartz diorite stock. Felsite dyke swarms and strong quartz vein systems crosscut the phyllite, phyllitic argillite, argillaceous siltstones and basalt to rhyodacitic porphyry tuffs. Silicification is manifested as crystalline to opaque to milky grey-white quartz breccias, stockworks and veins which range from 1 millimetre to 1 metre in width, with calcite often occurring as secondary veins.
Pyritization of up to 15 per cent is associated with these sili- cified zones. Upon weathering, moderate to intense gossans have developed and consist of hematite, goethite, jarosite and pyrolusite.
The rocks in the Exposure Showing have undergone various degrees of propylitic, argillic, sericitic and potassic alteration and contain abundant epidote and chlorite. Quartz and quartz-carbonate veins host pyrite, chalcopyrite, sphalerite, galena and trace pyrrhotite and tetrahedrite. In 1987, a sample from this silicified zone assayed 0.99 gram per tonne gold, 79.1 grams per tonne silver, 0.227 per cent copper, 1.005 per cent lead and 0.174 per cent zinc. Another sample from this mineralized quartz vein system assayed 0.995 gram per tonne gold, 41.1 grams per tonne silver and 2.954 per cent copper (Assessment Report 16957).
In 1988, Pezgold Resources visited the showing noting that a contact between a Coast Crystalline pluton and the country rock runs southeast through the Third Basin and that some quartz veins and shears adjacent to the contact are mineralized. Silicified, intermediate tuff with traces of pyrite and chalcopyrite near the diorite contact were sampled.
Work History
The first work recorded on the ground was performed by Anaconda Canada Exploration Ltd. for a Skyline Exploration Ltd., Placer Development Ltd. and Anaconda joint venture on the Burnie 14, Reg 10 and Stanley 7 claims around 1983. This program was carried out to follow-up on a helicopter-borne geophysical survey and consisted of geological mapping and limited trenching, prospecting, reconnaissance ground geophysics and stream sediment sampling. A total of 28 heavy mineral stream sediment samples and 20 rock samples were collected during the course of this program. The trenching and the five associated rock samples and the ground geophysics were conducted over an area just west of the present Eldorado claims. Anaconda’s work defined a silver-copper-lead-zinc-iron carbonate vein showing off the present Eldorado property with anomalous copper in heavy sediments in First Basin and anomalous gold in heavy sediments in Second Basin.
In 1987, Androne Resources Ltd. completed an exploration program on the Burnie 1-4 and Dan l-3 claims. Their work was comprised of geological mapping and prospecting (139 samples), silt sampling (56 samples) and contour soil sampling (272 samples). This program identified the Grace 2 showing, a northwest-trending shear zone with silicification and pyritization with malachite and which yielded significant gold, silver and copper assays. Androne also discovered the Grace 1 showing, a similarly-trending and mineralized shear zone, also with chalcopyrite and azurite.
Pezgold Resources Corp. conducted an exploration program in 1988 that was, in part, a continuation of the 1987 program that was halted due to adverse weather conditions. This program entailed grid-based soil sampling and VLF-EM surveys over the Grace showings and four trenches totalling 37 metres over the Grace 2 showing. A total of twelve chip samples were collected from two of these trenches. Results from these trenches were erratic and discouraging with maximum values of 11.9 grams per tonne gold and 1.5 per cent copper over 20 centimetres. The soil survey identified numerous, multi-station, but discontinuous anomalies with the strongest response in gold and base metals in the northern part of the grid (near the Grace 1 showing) and the strongest response in gold and silver in the southern part of the grid. A total of 5.3 line-kilometres of VLF-EM surveying was conducted over this same grid. The most pronounced anomaly outlined by this survey was associated with the Grace 1 showing. Several samples were taken at the Second Basin North showing.
The Burnie and Dan claims were allowed to lapse in the fall and winter of 1994 and were restaked in 1995 by David Javorsky as the Eldorado l-4 mineral claims. Javorsky carried out a limited program of prospecting in the Second Basin area including heavy mineral stream sediment sampling, and re-evaluation of the previous trenching.
In 1996, a total of 115 soil samples and 21 rock samples were collected by Golden Band Resources Inc on the Eldoradao claims (Assessment Report 25009).
During 2009 through 2011, Skyline Gold Corp. completed programs of prospecting, geochemical (rock and soil) sampling, trenching, airborne and ground geophysical surveys and 23 diamond drill holes, totalling 5676 metres, on the area as the Iskut property
