Publication Type:Book Chapter
Source:Report of activities 2012; Manitoba Innovation, Energy and Mines, Manitoba Geological Survey, Manitoba Geological Survey, Winnipeg, MB, Canada, p.104-113 (2012)
Keywords:Canada, cleavage, deformation, faults, folds, foliation, gold ores, host rocks, lithostratigraphy, Manitoba, metal ores, Snow Lake Manitoba, structural analysis, tectonics, thrust sheets, Western Canada
The New Britannia mine is a structurally controlled gold deposit hosted in mafic and felsic volcanic and volcaniclastic rocks. Mineralization is spatially associated with the hangingwall of the McLeod Road Thrust (MRT), and the gold deposits are located at stratigraphic contacts between units of contrasting competency at the intersection of a fault and a secondary structure, typically a fold hinge. Completion of the 2012 lithostratigraphic mapping of the McLeod Road-Birch Lake thrust panel (MB panel) has identified additional thrust faults, which repeat stratigraphic units of the panel. These structures appear to be truncated by the MRT and have been interpreted as early D (sub 1) structures. The main foliation in the MB panel (S (sub 1) ) is defined by the flattening of the clasts and is interpreted as a fabric formed during D (sub 1) folding and thrust imbrication of the MB panel. The S (sub 1) foliation is axial planar to the Nor-Acme anticline (F (sub 1) fold) and is consistently parallel to the MRT (late D (sub 1) thrust) contact. These D (sub 1) structures are overprinted by a spaced cleavage (S (sub 2) ), which overprints the Howe Sound Fault, the MRT and the Nor-Acme anticline. This fabric is correlative with the regional S (sub 2) fabric in the Burntwood Group, and it is inferred that the S (sub 2) fabric in the MB panel may be related to sinistral reactivation of the MRT. A spaced, steeply dipping, S (sub 3) fracture cleavage related to the Threehouse synform (F (sub 3) fold) consistently overprints all fabric elements. Gold mineralization is associated with D (sub 1) structures and there is evidence to suggest that emplacement was late D (sub 1) with later remobilization during D (sub 2) .
GeoRef, Copyright 2018, American Geological Institute.<br/>2013-058481<br/>McLeod Road-Birch Lake thrust panel