The Treaty Gossan occurrence is located near the western margin of a large gossanous area that occurs adjacent to the southeast of Treaty Glacier. The area is underlain by massive green and grey andesitic to dacitic tuff, lapilli tuff, tuff breccia and minor flows, of the Lower Jurassic Betty Creek Formation, Hazelton Group (Open File, 1988-4).
The gossan is a product of fault and fracture-controlled hydrothermal activity that has affected a larger area. Pyrite-quartz and sericite alteration minerals predominate, and the rocks are locally foliated to schistose in texture. The presence of native sulphur and alunite indicated that this is an area of acid-sulphate alteration characteristic of high levels of epithermal systems (Fieldwork 1987).
In 1987, chip samples were taken every 0.3 metre along a 4-metre length of massive coarse-grained pyrite vein and assayed 4.32 grams per tonne gold and 60.4 grams per tonne silver (Assessment Report 16841). The vein contains 10 to 15 per cent quartz, is 8 to 10 centimetres wide, trends 170 degrees and dips vertically (Sample KK-236, Map No.1 and No.2, Assessment Report 16841). The host rocks are excessively leached and limonitic. A sample taken of siliceous sinter in 1987 by D.J. Alldrick assayed 3.84 grams per tonne gold and 0.54 gram per tonne mercury (Personal Communication: D.J. Alldrick).
Alteration along the northern margin of the Main Gossan overprints interfingering mudstones, basaltic andesite flows and breccias, and epiclastic siltstone, wacke, and conglomerate. Minor, fine-grained dioritic intrusions cut these rocks in the area adjacent to the Eureka Zone.
Alteration in the Main Gossan overprints several different rock units, including intermediate composition volcanic flows and breccias, plagioclase-porphyry intrusions, and minor sedimentary rocks. In much of the gossan, strong to intense alteration and deformation overprints primary textures, making determination of protolith lithology uncertain. Uniform textures over large areas, and lack of evidence for an extrusive origin, suggests that these rocks represent a porphyritic intrusion. These porphyritic rocks are exposed in areas previously mapped as both monzonite and fine-grained plagioclase+hornblende porphyry. Textural differences between the rocks in these areas are interpreted to result from different styles of alteration, rather than changes in primary rock type.
Most rocks within the Main Gossan contain a penetrative foliation that varies in intensity from weak to intense. Cleavage intensity correlates with alteration style and intensity: most strongly altered rocks, characterized by an alteration assemblage of quartz+sericite+ pyrite plus/minus pyrophyllite contain an intense foliation while less-altered rocks contain a weaker foliation or spaced cleavage.
Mapping of alteration mineral assemblages within the Main Gossan defined a broad zonation characterized by a central core of kaolinite + quartz + pyrite alteration, grading outwards to sericite + quartz + pyrite, and peripheral chlorite + pyrite + carbonate alteration zones. Areas of massive silica occur on the east side of Sulphur Knob, and pyrophyllite occurs locally within some of the more intensely altered rocks in the core of the gossan. Much of the previous exploration work, including all fifteen of the diamond drill holes completed in the Main Gossan, are from an area along the western margin of the gossan referred to as the Eureka zone.
The Eureka zone is exposed in several north-easterly elongated outcrops, surrounded by morainal debris and ice. These outcrops contain irregular alteration zones dominated by either chlorite + pyrite, or kaolinite (sericite?) + limonite assemblages, with weak to moderate patchy silicification.
Veins infilled with variable proportions of fine to coarse-grained quartz, calcite, and pyrite form up to several volume percent of outcrops in the Eureka zone. Veins have steep dips, strikes varying from EW to N, and form weakly sheeted to stockwork zones. Previous exploration programs have collected hundreds of surface samples from trenches and outcrops in the Main Gossan. Nearly all the rock samples that contain significantly elevated gold values are from the Eureka zone area.
The Eureka zone was tested by seven diamond drill holes in 1994 and two additional drill holes in 1997. The drill holes tested a north-easterly strike length of approximately 400 metres. Several intersected long intervals containing weakly elevated gold grades (e.g.: DH 97-1, 169.2 metres at 0.46 gram per tonne), but none encountered significant high-grade intersections.
During the 2007 season, drilling was attempted in the Eureka zone and in a newly discovered area named ND zone, but quality of the rock made drilling a challenge and holes in the ND zone had to be abandoned above target depths. Best intersection for the Eureka zone shows 75.45 metres at 0.69 gram per tonne gold and 2.89 grams per tonne silver in hole TC07-02. (Assessment Report 30241). Hole TC07-04 shows 23.51 metres at 0.50 gram per tonne gold and 760.01 gram per tonne silver, even though recoveries in this last interval were reported as very poor (Assessment Report 30241).
Despite the intensity of alteration in the Sulphur Knob area to the southeast of the Eureka zone and the large number of samples collected there, very few samples produced elevated gold values.
In 2016, of the five holes drilled on the Treaty Gossan and the Eureka zone, three targeted anomalies identified by the Magnetotelluric (MT) survey and the remaining two targeted areas of interest identified by examination of surface exposures. While the three holes targeting the anomalies identified by the MT survey did not disclose significant mineralization, they were reported to have provided critical information useful for interpreting both the geology and the MT survey. The two further holes, including one in the Eureka zone, also provided critical information useful for interpreting the MT survey and did reveal mineralization as follows: Hole E-16-05 intersected intermittent values from near surface to a depth of 276 metres, including 0.459 gram per tonne gold over 15 metres from 27 metres to 42 metres, 0.473 gram per tonne gold over 16.5 metres from 172.5 metres to 189 meters, and 0.438 gram per tonne gold over 12 metres from 264 metres to 276 meters (Tudor Gold Corp, News Release, December 22,2016).
The Treaty Gossan was initially discovered and staked by Charles Knipple and Tim Williams in 1928. Consolidated Mining and Smelting Co. optioned the property the same year and after initial prospecting let the option lapse. In 1953, Williams and Knipple returned to the Treaty area and discovered a narrow silver-rich vein at the southwest corner of the nunatak and tetrahedrite-rich boulders on the Treaty glacier; no source for the float was identified. Prospecting by several companies between 1953 and 1980 on the property failed to identify significant mineralization. In 1981, E&B Explorations optioned the property from E. Kurchkowski and carried out a program of regional prospecting and geological mapping. No significant mineralization was discovered. In 1984, Teuton Resources Corp. acquired the claims and carried out prospecting in the area. During 1985 and 1986, Teuton Resources Corp. continued exploring the Treaty area with programs consisting of mapping, prospecting and silt sampling. In 1987 the Konkin zone (104B 171) . was discovered in the West Nunatak area. This discovery enabled Teuton to carry out blast trenching, rock sampling, grid-controlled soil sampling and diamond drilling on the West Nunatak during 1987 and 1988.
In 1989, the property was optioned by Tantalus Resources. From 1989 to 1992 Tantalus carried out mapping, trenching, diamond drilling, sampling and geophysics on the West Nunatak, Treaty Nunatak and Orpiment zones. These efforts culminated in the discovery of the AW-Ridge and Goat Trail zones (104B 172) on the West Nunatak and the Mama Susu zones (104B 370-375) on the GR2 claims. Between 1987 and 1992 a total of 1437 metres were drilled in 18 diamond drill holes on the Konkin, AW, Goat Trail and GR2 zones.
In 1993, the Eureka zone was discovered on the Treaty Nunatak where the Treaty Gossan is located. The zone comprises a core of silicification within advanced argillic alteration which returned 4.63 grams per tonne Au over 9.1 metres including 9.33 grams per tonne Au over 1.6 metres. Prime Resources Group Inc optioned the Treaty Creek property in 1994 and completed a two-stage program of 1:5000 and 1:2500 scale geological mapping, 90 metres of blast trenching in 11 trenches and 8 diamond drill holes totaling 866.42 metres. During the program 206 rock samples and 9 whole rock geochemistry samples were collected on surface and a total of 596 core samples were collected for analysis. The first stage comprised 1:5000 scale mapping of the Treaty Nunatak and 1:2500 scale mapping, trenching and rock sampling of the Main Gossan and the Orpiment zone. A total of 60 chip samples were taken from 11 trenches which traced the Eureka zone over 370 metres of strike length. A total of 9.7 kilometres of grid was re-established on the Main Gossan and 1.2 kilometres of new grid developed on the Eureka zone to assist in geological mapping and rock sampling. Work concentrated on testing the mineral potential of the Eureka zone identified during 1993. Stage 2 of the program involved drilling seven holes totaling 634.9 metres on the Eureka zone and one hole totaling 231.5 metres on the Orpiment zone. Continued geological mapping concentrated on the Goat Trail zone and evaluation of the AW and GR2 zones.
In 1995, with Explore B.C. Program support, Teuton Resources Corporation completed 77 metres of trenches and collected and assayed 96 rock samples from the AW and Ridge Veins zones, 3.4 kilometres west of the Treaty Gossan occurrence. Best trench results from the AW zone were 3.7 grams per tonne gold, 1168.9 grams per tonne silver and 2.9 per cent lead across 2.7 metres; best values from the Ridge Veins zone were 136.7 grams per tonne silver and 2.22 per cent lead across 1.5 metres (Explore B.C. Program 95/96 - G167).
Teuton and Global Explorations Ltd. drilled 8 holes on the property in 1997.
Heritage Explorations Ltd., becoming active in the Treaty Creak area in 2001 became the operating company to explore a 2200-unit claim consolidation in the Iskut district. St. Andrew Goldfields Ltd. and Zebrex Holdings Inc. held a controlling interest in Heritage. The property largely surrounds the Eskay Creek holdings of Barrick Gold Corp. and covers favourable folded stratigraphy from the McKay syncline eastward to the McTag anticlinorium, including the Treaty Creek and Bonsai prospects optioned from Teuton Resources Corp. Heritage undertook an ambitious digital compilation to build a comprehensive topographic, geological, geochemical and geophysical model to explore for Eskay Creek-type precious metal mineralization.
In 2003, Lewis Geoscience conducted field mapping at the request of Geoinformatics Exploration. Geoinformatics was coordinating and conducting much of the 2003 exploration programs for Heritage Exploration Ltd. who held an option on several claims in the Treaty Glacier area.
In 2004, Heritage Exploration acquired mineral rights over an extensive area in the Eskay Creek region of north-western British Columbia. Fieldwork at Treaty Creek in 2003 by Peter Lewis greatly improved the knowledge and understanding of the various zones in the area. The geological mapping and evaluation highlighted several areas for follow up work. Re-evaluation of airborne EM data indicated a porphyry target 1.5 kilometres southeast of the East Treaty (Eureka) prospect. The porphyry target was drill tested in 2004 with a 496-metre hole at UTM 430959E, 6271940N (Assessment Report 27578). The hole was collared in a quartz sericite pyrite altered felsic to intermediate volcanic, part of the highly altered prominent Sulphur Knob unit exposed to the northwest of the drill site. Results were disappointing. Unaltered intermediate to mafic volcaniclastics with minor argillites were intersected. An airborne EM-magnetic survey was flown late in the 2004 field season. Both the Eskay-SIB trend and the Treaty Glacier areas were covered. The survey was undertaken by Aeroquest Limited using their AeroTEM time domain system.
In 2007, American Creek Resources Ltd. optioned the property from Teuton Resources Corp. and conducted a diamond drill program totaling 5,467.66 meters in the Eureka, ND, Copper Belle and GR2 zones. Mineralized altered quartz monzonite was intersected in core on the Copper Belle, a bulk-tonnage type gold-copper-molybdenum porphyry occurrence.
In 2008, American Creek conducted a ground VLF-EM survey over the gossan immediately east of the Eureka zone, covering an airborne AeroTEM anomaly obtained from Aeroquest when the Treaty property in the Eskay Creek area was surveyed during September and October 2004. At the same time, drillcore from Copper Belle and GR2 zones was re-logged and re-interpreted.
he 2009 Treaty Creek drill program consisted of 32 holes with a combined total of 9519.50 metres of diamond drilling within four separate mineralized occurrences: Copper Belle, GR2 (104B 370), Treaty Ridge and Eureka (104B 078). A total of 11 holes were drilled on the GR2 zone (Mama Susu); 17 on the Copper Belle., 3 on the Treaty Ridge and 1 on the Eureka.
After the 2009 drill program was complete, work on the property was suspended due to a legal dispute between American Creek Resources Ltd. and Teuton Resources Corp.
The 2010 and 2015 field seasons were lost due to property title litigation between Teuton Resources Corp and American Creek Resources.
In 2016, the property legal dispute between American Creek and Teuton Resources was settled. The Treaty Creek project soon became a 60:20:20 joint venture with Tudor Gold as operator (60 per cent owner). Teuton and American Creek Resources each own a 20 per cent carried interest, meaning neither company must contribute to exploration costs until a production notice is made.
In 2016, Tudor Gold Corp conducted a Magnetotelluric (MT) survey on a portion of the Treaty Creek property prior to a drill program. Tudor Gold drilled eight holes on the Treaty Creek claims in 2016. Three holes were drilled on the Copper Belle are including two on a new zone to the northeast. The remaining five holes were drilled on the Treaty Gossan and Eureka zone (104B 078)
In 2017, Tudor drilled 13,722 metres in 27 diamond-drill holes on their Treaty Creek property. The target was the Copper Belle zone.
In 2020, Tudor Gold Corp. completed 52 diamond drill holes, totalling 45 517 metres, on the Goldstorm (MINFILE 104B 704) and Perfect Storm zones of the Treaty Creek Gold property.
Refer to Copper Belle (104B 518) for related geological and work history details which pertain to work done on the Eureka area, all part of the Treaty Creek property.