Tusks
North and South Tusks
View of the Tusks looking northwest. Conductive tusks are shown in magenta and underlying the Thor epithermal deposit
What Do the Tusks Look Like?
The “Tusks” at Thor are real geological features — large, deep, conductive bodies beneath the Thor epithermal deposit — and they have a very specific geometry and physical character. They are not exposed at surface, but MT geophysics have outlined them clearly. They form one of the most important structural elements in the entire Thor system.
Elliptical in plan view — two parallel, elongated bodies (North Tusk and South Tusk).
Elliptical in plan view — two parallel, elongated bodies (North Tusk and South Tusk).
- Drill hole Thor‑242 penetrated the top of the South Tusk at ~576 m depth and encountered:
- • Black graphitic schist • Pyrite “bombs” up to 4 cm • White altered fragments • High graphitic carbon content (4.7% C in the black schist)
Drill core from hole Thor-242-549m showing what Taranis calls the 'Bomb Unit". This drill hole contains large fragments of pyrite and bleached grey color patches.
What are the Tusks?
Additional Information
The Tusks at Thor are two areas of low resistivity that wrap around the Thor epithermal deposit. There are the South and North Tusks, and each of these areas corresponds to a physical area within the host rocks at Thor having resistivities in the < 70 ohm*m values.
Magnetotelluric data are inverted to produce 3‑D electrical resistivity models that reveal the geometry of faults, intrusions, alteration zones, and potential ore-bearing structures. The core idea is to take the MT measurements—natural variations in electric and magnetic fields—and solve the inverse problem to find the subsurface resistivity distribution that best explains those signals.
At Thor, the Tusks are known to be related to hydrothermal alteration related to the Thor epithermal deposit as the Tusks crosscut the host rocks and underlay the epithermal deposit. Areas of low resistivity can be related to clay alteration, sulfide mineralization or carbonaceous material
Magnetotelluric data are inverted to produce 3‑D electrical resistivity models that reveal the geometry of faults, intrusions, alteration zones, and potential ore-bearing structures. The core idea is to take the MT measurements—natural variations in electric and magnetic fields—and solve the inverse problem to find the subsurface resistivity distribution that best explains those signals.
At Thor, the Tusks are known to be related to hydrothermal alteration related to the Thor epithermal deposit as the Tusks crosscut the host rocks and underlay the epithermal deposit. Areas of low resistivity can be related to clay alteration, sulfide mineralization or carbonaceous material
The only glimpse of the Tusk comes from a deep drill hole that targeted this feature in 2024 deep drilling (Thor 242) and is shown in the picture above. These rocks are highly sheared and contain large 'bombs' of pyrite that have a brassy yellow color.One thing is clear about the origins of this unit - It crosscuts the sedimentary folding associated with the Silver Cup Anticline, and therefore it is related to a hydrothermal event that occurred after formation of the Silver Cup Anticline.
It does not appear to be directly related to the formation of the epithermal deposit, as this hydrothermal event was too small to have produced such a large concentric feature. What it does appear to be spatially related to is the large I-1 intrusive feature, and for this reason it is one of the main reasons to believe that Thor is underlain by a large, buried calc-alkaline intrusive body.
It does not appear to be directly related to the formation of the epithermal deposit, as this hydrothermal event was too small to have produced such a large concentric feature. What it does appear to be spatially related to is the large I-1 intrusive feature, and for this reason it is one of the main reasons to believe that Thor is underlain by a large, buried calc-alkaline intrusive body.