Geology of the Thor Ag-Pb-Zn-Au-Cu Deposit
Since 2007, Taranis Resources Inc. has completed 152 drill holes, 35 trenches and extensive geophysical
and geochemical surveys on the Thor Property. The exploration work has outlined an extensive Ag-PbZn-Au-Cu Deposit that covers five old “mines” including (from south to north) the Broadview, Great
Northern, True Fissure, St. Elmo and Blue Bell deposits.
Roscoe Postle Associates Inc. is currently completing a detailed assessment of the Resource at Thor and
this is of obvious importance to Taranis Resources Inc. However, understanding the basic geological
controls on mineralization is of prime importance since it remains the best guide to finding other areas
of mineralization at Thor that can augment the existing Resource Base.
In 2012, Taranis geologists completed detailed mapping of the Thor deposit and surrounding area, and
were able to obtain a very concise picture of the main controls of mineralization at Thor. In addition, a
number of important discoveries were made that included some very high-grade gold occurrences (SIF
and Gold Pit areas), and repeated areas of sulphide mineralization in the footwall of the known deposit.
The Thor Deposit sits along a major transition from underlying carbonaceous sediments to an overlying
sequence of greywacke. This transition is commonly marked by the presence of tuffaceous sedimentary
rocks and massive and disseminated sulfide horizons (“Primary Sulphides”) that form the Thor Deposit.
The primary sulphides are delicately laminated - but are commonly annealed to form coarse-grained
sulphides. The coarse-grained variety is the most common, and was the result of later deformation and
emplacement of quartz masses into the sulphide horizon.
Structural geology shows that most of the known mineralization is associated with the east limb of a
major antiform structure called the Thor Antiform – but there is increasing evidence to show that the
west limb of this anticline may also be mineralized.
Primary bedding – and most importantly the sulphide deposits that form the Thor deposit – has been
folded into tight northwest-trending folds that plunge shallowly to the north-west. In some areas, this
has led to repetitions in the sulphide-bearing horizon in the footwall of the known deposit and these are
now top-priority exploration targets.
Sometime after the deposition of the Primary Sulphides along the major stratigraphic contact, and
perhaps during the folding of the deposit – large quartz masses were emplaced along the favorable
sedimentary contact. In many places, these have “assimilated” large volumes of sulphide and constitute
an important part of the Resource at Thor (“Quartz-Sulphide Breccia”).
Superimposed on folding is a foliation surface that dips steeply to the east, and commonly has faulted
the sulphide deposits found along the bedding surface. In places, this foliation surface is also
mineralized although the metal content is decidedly lower and is quartz-dominated. This surface is also
commonly faulted and slickensided, and movement indicates a largely strike-slip motion. There is some
compelling information to suggest that the True Fissure Deposit has been faulted along this surface, and
the bottom portion remains undiscovered.
The top of the Thor Antiform is dominated by a number of gold occurrences that have never been
explored, and are very unique and are dominated by quartz, free gold (multi-ounce) and trace levels of
lead. The most impressive of these is the SIF Occurrence that is associated with a major Northwesttrending VLF conductor and associated EM-37 Conductors. While they exhibit clear structural control
along fault surfaces, the gold has probably been derived from the main Thor Sulphide horizon, and has
been remobilized into structures peripheral to the main sulphide deposit.
In conclusion – Thor is a syngenetic sulphide deposit that has undergone extensive modification by
folding and faulting. This observation will help focus exploration in areas that are capable of hosting
more mineralization at Thor.