Surficial Geology, Gnawed Mountain Area, British Columbia, Parts of NTS 92-I/6, NTS 92-I/7, NTS 92-I/10, and NTS 92-I/11

The Gnawed Mountain area includes the Highland Valley Copper mine (porphyry Cu-Mo) which is a major copper producer in Canada. The most areally extensive glacial sediment in the region of the mine is till deposited during the Late Wisconsinan Fraser Glaciation. Glaciers dominantly flowed south to southeastward during this glacial event as indicated by the orientation of numerous drumlins and flutings. During ice retreat, lateral meltwater channels were eroded in the flanks of valleys and the hillsides ofmountains indicating that ice occupied low ground when higher elevations were ice-free. Accumulations of glaciofluvial sand and gravel, too small to be mapped at this scale, can be found in proximity to these meltwater channels. The glaciofluvial drainage was generally to the south during ice retreat with aggradation of glaciofluvial sediments in the Guichon Creek valley. Glacial lake sediments in the Witches Brook valley were deposited in a glacial lake which formed when the eastward drainage was blocked by a mixture of ice and sediments. Mine tailings (anthropogenic deposits) are present near the open-pits and in the valley which extends northwest from the mine (previously occupied by Pukaist Creek). Limited field work was completed in this region in 2011 and 2012. Field station locations are shown on the map.