The Shot Rock Gold Property
Seabourne Resources Inc., a wholly-owned subsidiary of Northern Shield Resources, has signed an option agreement with a local prospector to earn an 80% interest on the Shot Rock Property in Nova Scotia.
To earn its interest, Seabourne must incur $2 million of exploration expenditures on the property within 4 years and make cash and share payments to the prospector over the same time period.
The Shot Rock Property is composed of 1,200 mining claims units staked under the terms of the Mineral Resources Act of Nova Scotia, which represents a total area of 185 square km. It is located between New Glasgow and Antigonish, and covers an epithermal gold setting of a type not previously recognized in Nova Scotia.
Seabourne’s decision to acquire the claims now called the Shot Rock Property was based on the hard work of a local prospector who had spent years diligently compiling data from numerous sources, prospecting old reports in libraries as much as the brooks and mountains, and after self-learning geology, re-interpreting the source of the gold that he was finding in the streams.
He pitched his theory on this gold project to Northern Shield at a mining exploration convention in Toronto in 2017. Shortly thereafter, we decided to throw our resources behind him and agreed to explore the project through an Option Agreement.
- Gold panned from streams that appears to be related to a specific geological unit
- Boulders with low grade gold but with pathfinder elements (including Hg, As and Sb) associated with epithermal gold mineralization not previously recognized in Nova Scotia
- Up to 44,000 ppb Au in historic Heavy Mineral Concentrate samples (sources on map).
- Potential for District-Scale mineralization comparable to deposits in Nevada, USA, a prolific gold producer
- Geologists from Department of Natural Resources have identified similar rocks 80 km to the west
The Shot Rock Property is located in the Antigonish Highlands, along the southern margin of Avalonia, a fault-bounded terrane between the Meguma Terrane to the South and the Ganderia Terrane to the North throughout the northern Appalachian orogen. The following descriptions are mostly based on White (2012) are references therein.
The oldest rocks found within the property are part of the Late Proterozoic Georgeville Group, including units from the Keppoch, James River and Bears Brook formations. The three formations are in conformable contact and include mostly volcanic rocks (mostly lapilli tuff of rhyolitic or dacitic but local basaltic compositions) and sedimentary rocks (laminated siltstone and cherty siltstone, sandstone, arkosic sandstone, and conglomerate) but felsic and mafic dikes and sills are not uncommon.
The bulk of the property is underlain by rocks from the Silurian Arisaig Group composed of shales, mudstone, siltstone and sandstone sequences (some fossiliferous) and red carbonate units and limestone. There are no known volcanic rocks nor sills and dikes associated with the Arisaig Group.
About Epithermal Gold
The following description is mostly based on a thorough compilation paper by Simmons et al. (2005), in which references to a large number of relevant papers can be found.
Epithermal systems have been and continue to be a very important source of gold and even more important source of silver. The typical orebody found in an epithermal system varies in shape, size and grade, and can easily be hidden underneath a blanket of barren alteration or even unaltered volcanic rocks. Deposit-size to district-size range from <10 km2 to 200 km2.
Drilling is crucial in exploring for epithermal deposits because surface features may not be representative of what is at depth.
Efficient exploration must include the integration of the following at every scale, from deposit to regional:
- Geological data – vein mineralogy and texture, patterns of hydrothermal alteration
- Geochemical data – patterns of dispersion
- Geophysical data – three dimensional signatures
Deposits form in the lower temperature, shallow portion (< 1.5 km depth and < 300° C) of a high temperature hydrothermal system.
This type of hydrothermal system most commonly develops in association with magmatic sequences of andesite, dacite and rhyolite of calc-alkaline and alkaline affinity, which are related to volcanic arc at convergent margins, intra-arc, back-arc and postcollisional rift settings. Au-rich deposits (low Ag/Au ratio) are also found in tholeiitic bimodal (basalt-and rhyolite) systems.
The mineralization develops in zones of high permeability within the volcanic rocks genetically related to the hydrothermal system and in the older basement rocks below them. Steep dipping veins are generally host to the highest-grade ore. Lower-grade but potentially high tonnage ore can also be found in breccias, coarse clastic rocks and intensely leached rocks.
Epithermal deposits are historically classified based on either:
- Alteration and gangue mineral assemblages
- Metal content
- Sulphide content
- Sulphide mineral assemblages
The first is generally preferred because potentially high degree of oxidization of the ore can make the other three methods difficult.
Two main types or mineral assemblages reflecting pH of hydrothermal solutions are recognized:
1. Mineralization associated with quartz ± calcite ± adularia ± illite
- Au-Ag, Ag-Au or Ag-Pb-Zn
- Au and Ag in electrum, acanthite, silver sulfosalts, silver selenides and Au-Ag tellurides
- Sphalerite, galena and chalcopyrite generally minor but occasionally dominant
- Quartz is main gangue, other minerals are chalcedony, adularia, illite, pyrite, calcite and/or rhodochrosite (in Ag-base metal rich deposits)
- Banded, cruciform-colloform textures, lattice textures of platy calcite and their quartz pseudomorphs
- Hydrothermal alteration is zoned from bottom to top:
- Deep regional propylitic
- Increasing amounts of clay, carbonate and zeolite minerals
- Proximal enveloping orebody is quartz, adularia, illite and pyrite
- Mineralization can be concealed under a regional alteration blanket of clay-carbonate-pyrite or kaolinite-alunite-opal ± pyrite
2. Mineralization associated with quartz ± alunite ± pyrophyllite ± dickite ± kaolinite
- Au ± Ag ± Cu ores
- Au and Ag as native gold and electrum
- Variable amounts of pyrite, Cu-bearing sulphides (mainly enargite, a high sulfidation indicator) and sulfosalts, sphalerite and telluride minerals
- Main gangue is massive and vuggy quartz and alunite, other minerals are kandite minerals (dickite and/or kaolinite) and/or pyrophyllite
- Hydrothermal alteration forms concentric envelops, from inside out:
- Ore-hosting vuggy and massive quartz
- Alteration zone of quartz and alunite, dickite ± kaolinite or pyrophyllite and illite or smectite
- Regional propylitic alteration
- Zone of illite or pyrophyllite alteration may occur in the roots below deposit
Hibbard, J P, van Staal, C R, Rankin, D W, Williams, H. 2006: Lithotectonic map of the Appalachian Orogen, Canada-United States of America. Geological Survey of Canada, "A" Series Map 2096A, 2 sheets, https://doi.org/10.4095/221912
Simmons, S.F., White, N.C. and John, D.A., 2005. Geological characteristics of epithermal precious and base metal deposits. Economic Geology 100th Anniversary Volume, pp. 485-522.
White, C. E. 2012: Preliminary geology of the Antigonish Highlands, northern mainland Nova Scotia; in Mineral Resources Branch, Report of Activities 2011, ed. D. R. MacDonald and E. W. MacDonald; Nova Scotia Department of Natural Resources, Report ME 2012-001, p. 75-91. https://novascotia.ca/natr/meb/data/pubs/12re01/12re01_14White.pdf