Summary:
The Klaza project hosts a multi-episodic epithermal vein system of both the intermediate sulphidation and low-sulphidation classes. These veins are interpreted to be in the distal setting of a porphyry complex which is located near the centre of the Mount Nansen Gold Camp.
The metals of primary interest at the Property are gold and silver. These metals are intimately associated with lead, zinc and copper in various forms and concentrations throughout the mineralizing system. Gold and silver enriched mineralization is developed within a northwest trending structural corridor, which is interpreted to have focused fluid flow away from weak porphyry centres related to a Late Cretaceous stock in the southeastern corner of the Property. Several of the mineralized structural zones are continuously mineralized for strike lengths of up to 2,400 m, and at least one of the structures is mineralized to a depth of 520 m down-dip from the current geographic surface. The mineralized structures remain open to extension along strike and down-dip.
Fluid inclusion work reveals that the veins formed at shallow depths (<1 km) and have low to intermediate sulfidation epithermal fluid characteristics (Main, 2015). Textures and mineralogy observed at the Property share a number of similarities with Carbonate Base Metal (CBM) deposits (Tarswell and Turner, 2013).
CBM deposits are a recently recognized sub-class of epithermal deposits that encompass a family of similar deposits located around the world. CBM deposits have mainly been discovered around the Pacific Rim and include multi-million ounce gold deposits such as Porgera (New Guinea), Buritica (Colombia) and Kelian (Indonesia).
The CBM class of deposits has yet to be identified elsewhere in the Yukon, but some researchers have recognized that mineralization on the Property has some of the characteristics of mineralization now categorized as CBM deposits (ex. Smuk, 1999). Given the limited academic research on the Property and the absence of significant syn-mineralization carbonate, more studies need to be undertaken.
The Property lies within the northern part of the Mount Nansen Gold Camp (MNGC), a northwest trending structural belt that hosts more than 30 known mineral occurrences, several of which are categorized as deposits and have produced historically and as recently as 1999 (Hart and Langdon, 1997).
Mineralization within the MNGC is dominated by gold-silver rich structures associated with a zonation model ranging from weak porphyry copper molybdenum centres, outward to transitional anastomosing sheeted veins, and lastly to more cohesive and continuous base and precious metal veins. The age of the mineralizing events within the MNGC is now considered to be Late Cretaceous.
The main mineralized structural zones range from 1 to 100 m wide and are usually associated with feldspar porphyry dykes. Mineralization occurs within veins, sheeted veinlets and some tabular breccia bodies. The host granodiorite exhibits pervasive weak argillic alteration immediately adjacent to, and up to 30 m peripherally from, them. Sericitization and potassic alteration are developed directly adjacent to hydrothermal channel ways. The granodiorite is magnetite bearing except where the magnetite has been replaced by sulphide minerals around and within mineralized structures.
Depth of surface oxidation ranges from 5 to 100 m below surface, depending on fracture intensity, the type of mineralization and local geomorphology. The deepest weathering occurs in wide, pyritic veins located along ridge tops or on south facing slopes.
Detailed evaluation of oriented drill core and measurements taken from trench exposures has identified two main structural orientations that control mineralization. The primary structural set strikes between 135° and 155° and dips 60° to 80° to the southwest. The secondary mineralized trend strikes between 110° and 130° and dips 60° to 70° to the south. The secondary structures may represent either Riedel shears of the primary structural set or a separate structural event altogether. The best gold mineralization is sometimes localized in areas where the two structural trends converge. The plunge of these structural intersections is towards the southeast.
Quartz is the dominant gangue mineral in veins in Work Area 2. It occurs in a variety of textures including chalcedonic, comb, banded, speckled and vuggy. Smoky quartz is the most common colour variation, but milky and clear quartz are locally abundant. Carbonate occurs mainly as ankerite and rhodochrosite and typically ranges between 5 and 20% of the veins by volume.
Breccias form tabular bodies consisting of heterolithic wallrock clasts, which include granodiorite and various volcanic or sub-volcanic lithologies. Matrices are enriched with fine grained, disseminated to blebby pyrite, arsenopyrite, sphalerite and galena. Breccias are mostly observed within drill core from the Klaza zone where they range up to 2 m in width.
Mineralization within most structures is interpreted to be spatially and genetically related to porphyry dykes, which strike northwesterly and dip steeply to moderately toward the south. The dykes pinch and swell in three dimensions and are usually unmineralized. Some faults identified to date likely post-date emplacement of the dykes as they are occasionally cut by mineralized veins.
The known surface mineralization on the Dade claims (Work Area 3) is hosted in two, sinusoidal zones of quartz veining and stockwork (V1 and V2) striking about 040° and dipping 60°-75° north, hosted in coarse-grained hornblende-quartz granodiorite to diorite gneiss (Burrell, 2013). V1 (formerly, the Grizzly Vein) and V2 are epithermal quartz vein and stockwork zones that exhibit pervasive silicification and moderate to strong clay alteration. In 2011, trenching exposed V1 over widths of 9 to 20 m along a 175 m strike length and V2 over widths of 2 to 12 m along a 125 m strike length (Burrell, 2013). The veins comprise white to grey quartz with boxwork limonite and locally 1-3% disseminated arsenopyrite and pyrite.