Eruptive History of the Fort Selkirk Area, Central Yukon

Abstract

Lying at the large-scale tectonic boundary between the Yukon Tanana and northern extremity of the Stikinia and Quesnelia terranes, mafic eruptions have occurred over the past 4 million years in the Fort Selkirk area. Eruptions have included effusive (lava), explosive activity, and subglacial and subaqueous eruptions that produced hyaloclastite complexes. Eruptions have dammed or disrupted Yukon River at least five times. These volcanic rocks and interstratified sediments are collectively referred to as the Fort Selkirk Volcanic Group. Eruptions occurred from seven centers with activity progressively moving north. An explanation for the northern migration of volcanism is elusive at present.