Geology

Regional Geology

The Property geology is dominated by Siluro-Devonian stratigraphy that formed in a paleo-basin adjacent to the ancient North American Platformal sediments. The east-dipping and west-dipping thrusts, define the present margins of the Prairie Creek paleo-basin in which sediments accumulated.

Units within the Prairie Creek paleo-basin underwent structural deformation in the form of folds and faults during regional Laramide deformation. The prevalent regional structural trend is approximately north-south; the Prairie Creek paleo-basin is broken into a series of north-south trending, five to 20 kilometre fault blocks. Canadian Zinc’s mineral claims and leases overlie two major fault blocks of sediments: the Prairie Creek Block and western Gate Block.

The Prairie Creek block is located on the southern part of the Property. It is outlined by a one to two kilometre wide, doubly plunging antiform with a north-south trending fold axis. It is underlain by a conformable sedimentary sequence ranging from Lower Ordovician to Silurian in age. The antiform plunges at about 15 degrees to the north, so the geological units young in age to the north.

RegionalGeology2011 - CopyRegional Geology (Click to Enlarge)

Gate FaultWebpageGate Fault Structure Along Folded Mountain

Site Geology

The Mine Site is situated on the western flank of the Prairie Creek antiform, referred to as the Main Zone. It is Main Zone mineralization that was and is the focus for mine development and exploitation. The Ordovician, Upper Whittaker Formation is the oldest geological formation in this area. It is composed of interbedded cherts and dolomites that form the core of the Prairie Creek antiform. The Whittaker Formation is in turn overlain by a large exposure of the carbon-rich graphitic-shales/dolomites of the Road River Formation. The iron-bearing Cadillac Formation shales overly the Road River Formation and are located immediately adjacent to the mine site. The bluff-forming rocks immediately to the west of the mine site are formed by the cherty Arnica Formation which overlies the Cadillac Formation and forms the more resistant hilltops in the immediate vicinity of the Mine Site.

The Gate Block is located to the west of the main mining leases and overlies similar type rock assemblages to those found on the Prairie Creek Block. Grassroots exploration was completed on this ground to test for mineralization similar to that found in the Prairie Creek Block.

Four main styles of base metal mineralization have been identified on the Property: vein mineralization, stratabound sulphides (SMS), stockwork (STK) and Mississippi Valley type (MVT) mineralization. Base metal mineral showings occur along the entire 16 kilometre north to south length of the property.

 

MineStratigraphyWebpageStratigraphy and Structure Looking North From Zone 6

 

Mine Site Geology  June 2012 2Cross Section of Mine Site Geology

 

Vein Type Mineralization

The most significant mineralization on the property is the vein mineralization. Vein mineralization comprises massive to disseminated galena and sphalerite with lesser pyrite and tennantite-tetrahedrite in a quartz-carbonate-dolomite matrix. Secondary oxidation is locally developed to variable levels of severity, yielding mainly cerussite (lead oxide) and smithsonite (zinc oxide). Silver is present in solid solution with tennantite-tetrahedrite and to a lesser extent with galena. Vein widths vary between less than 0.1 metres and more than 5 metres. Overall averages indicate a horizontal thickness, but not a true thickness, of approximately 2.7 metres.

 

The most extensively developed vein is the Main Quartz Vein (MQV). Underground development has proved 940 metres of strike length and diamond drilling to date has indicated its continuance for a further 1.2 kilometres. The MQV trends approximately north-south and dips between the vertical and 55 degrees east with an average dip of 65 degrees east. It remains open to the north and evidence from a surface showing suggests it continues for a further four kilometres to the south. Diamond drilling to depth has indicated its continuance, but little information is currently available below an elevation of 600 metres amsl (i.e. about 250 metres below the Mine Site elevation).

 

Main Quartz VeinWebpageVein Mineralization In the Underground 930 Level, X-Cut 09

 

MQV CoreWebpageMineralized Quartz Vein Drill Core Intercept PC-04-144

Stratabound Type Mineralization

Stratabound (SMS) mineralization occurs at depth beneath the trend of the Prairie Creek Vein System over a strike length of more than 3 kilometres. SMS mineralization occurs close to both the vein system and the axis of the Prairie Creek anticline. An apparent thickness of 28 metres of SMS mineralization has been intersected in Main Zone drillholes where it occurs approximately 200 metres below 870 metre Level. The vein structure cuts through the SMS indicating the vein mineralization to be younger.

SMS mineralization is generally fine-grained, banded to semi-massive and comprises massive fine-grained sphalerite, coarse-grained galena and disseminated to massive pyrite and very little copper. SMS contains only half as much galena, but substantially more iron sulphide/pyrite than typical vein material. Silver is contained in solid solution within galena.

SMS CoreWebpageStratabound Massive Suphide Drill Core Intercept PC-04-150

 

Stockwork Type Mineralization

Stockwork (STK) mineralization occurs as a series of narrow massive sphalerite-tennantite veins developed at about 40 degrees difference in strike to the average trend of the MQV. This mineralization has developed in sub-vertical tensional openings formed by primary movement along the main vein structure. The sulphide mineral assemblages are similar to those outlined for MQV material. To date, the STK mineralization has only been located in around the exposure on the 930mL underground workings.

StockworksWebPageStockwork Mineralization in 930 Level

Mississippi Valley Type Mineralization

The MVT mineralization found on the property is comprised of colliform rims of sphalerite, brassy pyrite-marcasite and minor galena, with or without later dolomite infilling. The mineralization appears to occur discontinuously within coarse biohermal reefs of the Root River Formation, and always at approximately the same stratigraphic horizon. It appears to be classic MVT mineralization, insofar as it occurs in open cavity-type settings.

MVT SampleWebPageMississppi Valley Type Mineralization Sample