Volcanology of Northern Canada that remain unvegetated and appear to be only a few hundred years old. However, dating of sediments in a lake impounded by the lava flows indicated that the youngest lava flows could not be younger than mid-Holocene and could be early Holocene or older. Therefore, the most recent activity in the Fort Selkirk volcanic field is unknown. The lava flows from Volcano Mountain are unusual because they originate much deeper in the Earth's mantle than the more common basaltic lava flows found throughout the Yukon and are very uncommon in the geological record. This lava, known as olivine nephelinite, is
Lava River Cave ago. The source is believed to be near Mokst Butte southeast of the entrance. The same volcanic flow that formed the cave underlies much of the Bend area and almost reaches Redmond, Oregon. However, the specific vent that created the cave has been buried by several younger flows. The Lava River Cave was created by lava flowing downhill from a volcanic vent. The lava flowed northwest from the vent toward the Deschutes River. The flow began as a river of lava flowing in an open channel. Eventually, a lava crust solidified over the top of the flowing lava. This formed