Cinder cones along the east and west sides of the Iskut River (shown above), near its confluence with Forrest Kerr River, produced a minimum of twelve basaltic lava flows in the last 70 000 years. The lava flows commonly have clinkery surfaces and occasionally, preserved lava flow features. Several of the Iskut River lava flows were large enough to block the Iskut River; the river has subsequently cut down through the lava flows to form the Iskut canyon, which is an extremely rugged, narrow gorge and has among other things blocked the migration of salmon into the upper reaches of the Iskut River drainage. The youngest Iskut River lava flows have not been successfully dated, but are less than a flow dated at 2555 radiocarbon years before present (Hauksdottir et al., 1994). The Iskut River lava flows are part of the Iskut volcanic field, which includes several other young lava flows (< 100 000 years old) including Lava Fork, Hoodoo Mountain, Snippaker Creek, Tom McKay Creek, King Creek, and Second Canyon. All of the volcanoes in the Iskut volcanic field are part of the northern Cordilleran volcanic province (Edwards & Russell 2000).
-summary by Ben Edwards, Grand Valley State University, MI
Edwards, B.R. & Russell, J.K. 2000. The distribution, nature and
origin of Neogene-Quaternary magmatism
in the Northern Cordilleran Volcanic Province, northern Canadian Cordillera.
Geological Society of America Bulletin, v. 112, no. 8, 1280-1295.
Elliot, R.L., Koch, R.D., & Robinson, S.W., 1981, Age of basalt
flows in the Blue River Valley, Bradfield Canal quadrangle,
in The United States Geological Survey in Alaska; Accomplishments during 1979: USGS Circ. 823-B, B115-B116.
Grove, E.W., 1974, Deglaciation-A possible triggering mechanism for
recent volcanism: Internat. Assn. Volc. Chem.
Earth's Interior, Proc. Symp. Andean Antartic Volcanology Problems, Santiago Chile, Sept. 1974.
Hauksdottir, S. 1994. Petrography, geochemistry and petrogenesis of
the Iskut-Unuk rivers volcanic centres,
NW British Columbia. Unpub. M.Sc. Thesis, University of British Columbia, 253 p.
Hauksdottir, S., Enegren, E.G., & Russell, J.K. 1994. Recent basaltic
volcanism in the Iskut-Unuk rivers area,
northwestern British Columbia. In Current Research 1994-1A, Geological Survey of Canada, p. 57-67.
Souther, J.G., 1990. Iskut-Unuk River Cones, Canada. In Wood, C.A.,
& Kienle, J. (eds.). Volcanoes of North
America, Cambridge Univ. Press: Cambridge, p. 128-29