Wells Gray-Clearwater Volcanic Field - Geology - Holocene Epoch

Holocene Epoch

At the end of the last ice age approximately 10,000 years ago, massive floods from the melting glacial ice carved deep canyons into the underlying plateau-capping lava flows. Most of these canyons contain rivers such as the Murtle and Clearwater, and waterfalls such as Canim Falls, Moul Falls, Spahats Falls and the 141 m (463 ft) high Helmcken Falls. The faces of the basaltic lava flows and waterfalls remain vertical due to the nature of the basaltic lava flows. Basaltic lava shrinks as it cools and forms vertical columns of rock called columnar basalt. More recently, the southern end of the volcanic field has experienced continuous volcanic activity since the end of the last ice age. This volcanic activity occurred in three areas; Spanish Creek, Ray Lake and Kostal Lake which were followed by lava fountain eruptions creating cinder cones and lava flows.

Volcanism in the Spanish Creek and Ray Lake areas were synglacial but continued after the glacial ice had melted away. Two cinder cones, known as Flourmill Cone and Pointed Stick Cone, were created in the Spanish Creek area. Lava flows from the two cinder cones lie on glaciated bedrock without an intervening paleosol, indicating an early Holocene age.

Eruptions near Ray Lake built a cinder cone known as Dragon Cone and concluded with an approximately 16 km (9.9 mi) long ʻaʻā lava flow that has been radiocarbon dated at about 7,600 years old. This lava flow, known as "Dragon's Tongue", is at least 15 m (49 ft) thick at the proximal end, but thins to 3 m (9.8 ft) at the distal end, damming the southern end of Clearwater Lake. Tree molds are maintained within the lava flow at the lower end.

The latest volcanic eruption created a small tree-covered basaltic cinder cone at the east end of Kostal Lake called Kostal Cone perhaps as recently as 400 years ago, making it one of the youngest volcanoes in Canada based on tree-growth data.