Blackcomb Mountain 50-70 Million Years Older Than Whistler

Blackcomb Mountain is approximately 150 million years old, formed during the Jurassic Period from granodiorite, while Whistler Mountain is about 80 million years old, composed of sedimentary and volcanic rock from the Cretaceous Period. The Fitzsimmons Fault separates the two mountains and runs through Whistler's Ego Bowl and along Highway 99. Prospector Jimmy Fitzsimmons staked copper claims in the area, and the fault and creek bear his name. Blackcomb was pushed up by the Pacific Plate, while Whistler rose due to the Fitzsimmons Fault. The Horstman Glacier on Blackcomb is named after prospector Henry 'Harry' Horstman, who arrived in 1913 but did not stake claims on Blackcomb. The Alta Lake Mining Company mined bog iron from the Fitzsimmons Delta from 1916, producing up to 150 tonnes per day, transported to Squamish and then Washington state. Geologist Steve Carney explained that the diverse geology results from rocks transported by oceanic plates and accreted to continental America starting 100 million years ago. The area is proposed as a UNESCO GeoRegion.