Magmatism and Metallic Mineralization of the Rocky Mountain Fold-and-Thrust Belt, Southwestern Alberta (NTS 82G, 82H and 82J): Mineralogy, Geochemistry and Petrology of Selected Occurrences

This report provides whole-rock and in-situ geochemical and quantitative mineralogical analyses and interpretation for samples of magmatic and sedimentary rocks from the Rocky Mountain Foreland fold-and-thrust belt of the Canadian Cordillera in southwestern Alberta.

Analyzed samples were taken from selected outcrops of

- the Mesoproterozoic Belt-Purcell Supergroup and mafic sills and dikes, and the Cretaceous alkaline sills and dikes in the Clark Range area;

- the Crowsnest Formation volcanic and epiclastic rocks in the Crowsnest Pass area;

- the Oldman River Mississippi Valley-type lead-zinc prospect within the Upper Devonian Palliser Formation dolomitized limestone on the east flank of Mount Gass; and

- the overlying Devonian/Mississippian Exshaw Formation black shale.

Based on geochemical and petrological evidence, the authors propose that the Belt-Purcell intracontinental rifting accompanied by voluminous tholeiitic- to alkali-basalt magmatism may have been triggered by a Mesoproterozoic mantle plume. Their observations and study of the exposed strata in the Rocky Mountain Foreland fold-and-thrust belt of the Canadian Cordillera in southwestern Alberta can help to better understand the geology, depositional environments and mineral resources for the rest of Alberta, where equivalent strata in subsurface are not as easily studied.