not_specified

A copy of this thesis is available at the EMR library – QE195.M3 1997. This thesis is available online at https://doi.org/10.7939/R3DJ58N76.

A mineral assessment of the Tombstone study area was undertaken by the Department of Economic Development in the summer of 1998 at the request of the Department of Renewable Resources. The purpose of the mineral assessment was to produce a mineral potential map, which was to be used to assist with the finalization of the boundaries of the Tombstone Territorial Park. Following an initial compilation, a field program was designed to document known mineral occurrences, test and improve the existing regional mapping, investigate geochemical anomalies, characterize favourable environments for mineralization, sample for lithogeochemistry, and prospect for mineralization. A field program resulted in the discovery of several new mineral occurrences, as well as the discovery of previously unmapped geological formations. Fieldwork was followed by a compilation phase that integrated the new information to the existing geoscientific data. The geology of the study area was subdivided into thirteen geological tracts. A panel of five industry and government experts, familiar with the geology, mineral occurrences and mineral deposit types to be found in the area, was convened in June 1999. Based on the final compilation and their expertise, they produced a relative ranking of all the tracts according to their potential to host mineral deposits, from highest potential to lowest. The highest-ranking tracts are those that include, or are near the Cretaceous intrusions (Tombstone, Mount Brenner and smaller intrusions) and have strong potential for intrusion-hosted (Fort Knox-type, porphyry uranium, skarn) and intrusion-related (skarns, veins, replacement) mineralization. Other tracts demonstrate potential for Wernecke Breccia, shale-hosted nickel sulphide, ultramafic-hosted nickel and listwaenite, Carlin-type, Mississippi Valley-type or replacement lead-zinc, as well as volcanogenic mineralization. A final boundary was adopted in December 2000; it includes land outside of the original study area. This final boundary therefore includes areas that were not assessed in this study. All our wildlife sightings were documented and were included in the subsequent wildlife survey.

not_specified

We present new field and U-Pb analytical data from the Sonora Gulch Project that demonstrate a protracted history of polymetallic mineralization (Au-Ag-Cu-Zn ± Mo) associated with several pulses of Cretaceous magmatism. Recent exploration on the Sonora Gulch Project has highlighted the presence of two important mineralized zones: the Nightmusic zone, a mesothermal Au-enriched base metal skarn, and the Amadeus zone, an epithermal Au-Ag system. Four U-Pb age dates determined from each of two feldspar porphyry dykes (ca. 74 Ma), a weakly mineralized quartz porphyry stock (ca. 75 Ma) within the Nightmusic zone and the Au-Ag mineralized Amadeus stock (ca. 75 Ma), demonstrate the widespread occurrence of Late Cretaceous magmatism. The age determinations indicate that mineralization occurring within the Sonora Gulch project area are temporally equivalent to the Casino Cu-Au-Mo deposit, located roughly 40 km to the west-northwest. These new data extend the currently known eastern limit of Late Cretaceous magmatism and associated mineralization.