Posted by: lillooetproject | March 15, 2009

Property Geology

The Port Douglas property covers a large portion of the Early Cretaceous Fire Lake pendant, one of several scattered Jurassic-Cretaceous pendants located in the southern Coast Mountains. The pendant is surrounded by plutonic rocks of the Coast Plutonic Complex. Rocks within the pendant are termed the Fire Lake Group and are correlated with the Gambier Group, based on lithological similarities. This correlation is important from a mineral potential perspective, since it suggests the potential for volcanogenic massive sulfide mineralization in the Fire Lake Group. The Britannia Mine near Squamish (65 km west-southwest of the Port Douglas property) is an example of massive sulfide mineralization within the Gambier Group. The Britannia Mine produced approximately 47.8 million tones, of ore grading 1. 1 % Cu, 0.65% Zn, 6.8 g/t Ag and 0.6 g/t Au between 1905 and 1977. At the time of the mine closure, drill indicated reserves were 1.4 million tones grading 1.9% Cu.

 

A number of regional structures are present. The oldest structure, situated southeast of the Port Douglas property, is a shallow angle south-southeast-directed thrust fault which emplaces rocks of the Peninsula Formation onto rocks of the younger Brokenback Hill Formation. Cutting the property from southeast to northwest is a major southwest directed, high angle thrust fault, regionally known as the Fire Creek Thrust. This fault has significance to exploration because of the spatial association of gold bearing quartz veins to the thrust. A major shear zone, the Harrison Lake shear, is situated within the Lillooet River valley. The Harrison Lake shear has been well studied by Ray (1986) and others, and is felt to be an important control for Tertiary plutonic activity and related epithermal style mineralization. The final phase of deformation seen in the region of the Port Douglas property consists of Tertiary northeast-striking dextral normal dip-slip block faults. Again, these structures have significance to exploration because they appear to control the emplacement of Tertiary felsic plutons and dykes which are regionally associated with epithermal gold mineralization.

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