Geologic Map and Structural Evolution of the Black Hills Creek Area in the Smash Minerals Whiskey Project, Yukon Territory. Jones, Stacie
This increase in activity in the Yukon-Tanana terrane from advances in the understanding of intrusion-related and orogenic gold mineralization, has led to the development of a joint academic-industry endeavour to further the magmatic, metallogenic and structural understanding of the area of interest. This project was developed and jointly- supported by Smash Minerals and the Yukon Gold Project, a joint MDRU-industry endeavour. Currently, the structural model developed by MacKenzie et al. (2006, 2008, and 2010) has helped elucidate the structural control on gold mineralization in the Golden Saddle deposit, Klondike District, and elsewhere in the western Yukon. Therefore, understanding the structural evolution of gold properties in the surrounding region is considered to be of considerable importance in locating new gold occurrences. The ultimate goal of this project was the construction of a geologic framework that respects all field observations. Supplementary analyses were used to define the structural evolution and timing and nature of mineralization of the Black Hills Creek area. The study area, approximately a 200m by 50m exposure of continuous bedrock, had been thoroughly exposed by previous placer operations along Black Hills Creek allowing for a detailed mapping study to be completed during the summer of 2011. Three main lithologic units were identified: a quartz-biotite schist, a quartzite and a felsic dyke. The entire map area had a pervasive foliation striking NW-SE and variably dipped to the SW. The felsic dyke commonly cuts this pervasive foliation at a low angle suggesting a later emplacement. U-Pb dating of monazites and zircons, using ID-TIMS and CA-TIMS methods, was done to establish ages of peak metamorphism and the timing of the felsic intrusion furthermore, Pb-isotopic analysis of sulphides were completed in an effort to correlate the timing and nature of mineralization to know mineralization in the surrounding areas. The study concluded that although all five phases of deformation anticipated from the model by MacKenzie et al. (2006, 2008 and 2010) are not present within the Black Hills Creek study area the structural evolution correlates with the regional development. With a peak metamorphic age of 260 m.y ago correlating to the Klondike orogeny and felsic dykes resembling both physically and chemically the Permian intrusives of the area it can be said that the Black Hills Creek area has a at least two events (D2 and plutonic intrusions) that parallel the region model defined by MacKenzie et al., (2006, 2008 and 2010).
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