Overview of Results from the Greenstone ... - Geology Ontario

Mine stratigraphic succession, have also been interpreted to be Theo’s and Fred’s flows, recognized at the
Potterdoal Mine north of the Warden Hill fault (Arndt 1977, Arndt, Naldrett and Pyke 1977). Thus, the
north limb of McCool syncline is interpreted to be repeated across the Warden Hill fault.
At Potterdoal Mine, the volcanic succession is divided into 2 units structurally repeated by the Buster
fault (Epp 1997, Epp and Crocket 1999). The lowest unit in the area consists of thick layered tholeiitic
flows: Theo’s flow and the Ore flow. The upper unit is a thick layered komatiitic flow: Fred’s flow.
Theo’s flow and the Ore flow are interpreted to be at the same stratigraphic level, the present
superposition of the flows being due to movement along the Buster fault (Epp 1997, Epp and Crocket
1999). The mineralization at Potterdoal Mine occurs in a breccia unit within a sedimentary and
volcaniclastic unit between the Ore flow and Fred’s flow. The breccia was interpreted to be “tectonic”
and to have formed in a scarp depression. Along strike from the “tectonic” breccia, mafic volcaniclastic
deposits are observed similar to the pyroclastic rocks at Potter Mine (Epp 1997, Epp and Crocket 1999,
Péloquin, Houlé and Gibson 2005).
The mafic to ultramafic volcanic contact favourable to volcanogenic massive sulphide deposits is
structurally repeated in the North Munro block (Figure 23): 1) at Potter Mine north of the Centre Hill
fault; 2) on the north limb of McCool syncline, south of the Warden Hill fault; and 3) at Potterdoal Mine
Figure 23. Map of the North Munro block showing the repetition of Fred’s and Theo’s flows (from Péloquin, Houlé and Gibson
2005, p.18). Mineral occurrence and deposit numbers listed are from Péloquin, Houlé and Gibson (2005, p.44, Table 2); the Potter
Mine (formerly known as the Centre Hill Mine) and Potterdoal Mine (numbers 11 and 9, respectively) are discussed in the text.
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