Let’s see – area residents have heard of the Bridge River Valley, the Bridge River Indian Band, the Bridge River Power Project and, yes, the Bridge River-Lillooet News.
But how many have heard of the Bridge River Cones?
The Bridge River Cones, sometimes referred to as the Lillooet Cones or Salal Creek Cones, is the name given to a volcanic field, located on the north bank of the Bridge River about 40 kilometres (25 miles) west of Gold Bridge. The cones sit atop a group of passes between the Bridge River and the Lord River, which flows north to the Chilcotin. They are located at the northern edge of the Garibaldi Volcanic Belt.
The Bridge River Cones are included in an article in the upcoming fall edition of British Columbia magazine called “British Columbia’s 18 Sleeping Volcanoes.”
Mount Meager, northwest of Pemberton, is also featured in the article about the province’s volcanoes, which the article describes as “dormant and beautiful in their slumber.”
According to the magazine, while there are hundreds of volcanic fields and volcanic centres in B.C., “there are only 18 proper volcanoes.” The largest cluster lies in the north near the coast, but others are scattered across the province.
Most of B.C.’s volcanoes last
erupted at the end of the Pleistocene Age about 10,000 years ago, while the most recent eruption occurred 250 years ago.
The Bridge River Cones, which have a height of 2,500 metres, cluster around Tuber Hill, a small basaltic stratovolcano formed by retreating glaciers. The last notable eruption was thought to be 1,500 years ago, but there may have been small lava flows as recently as 50 years ago.
According to the book, “Volcanoes of North America,” published by Cambridge University Press, Sham Hill, a 60-metre high volcanic plug is the oldest volcano in the field and has a potassium-argon date of one million years. The Sham Hill Plug is approximately 300 metres wide. The Salal Glacier Volcanic Complex has a potassium-argon date of 0.97 to 0.59 million years. Tuber Hill has an estimated age of 0.6 million years.
Mount Meager is located 50 kilometres from Pemberton at the northern end of the Pemberton Valley. It is topped by several eroded volcanic edifices including lava domes, plugs and overlapping lava flows, which form six major summits on the mountain.
Geologists and volcanologists say Mount Meager produced the largest volcanic eruption in Canada in the last 10,000 years About 2,400 years ago an explosive eruption formed a volcanic crater on the northeastern flank of the mountain, sending cascades of hot ash, rock fragments and volcanic gases down the slope.
According to the Smithsonian Institution’s Global Volcanism Program, that eruption would have been similar to the 1980 eruption of Mount St. Helen’s. The Mount Meager eruption sent a massive Plinian column at least 20 kilometres into the atmosphere and westerly winds carried volcanic ash from the explosion as far east as Alberta.