Lava Fork, NW British Columbia/SE Alaska

Location: 56.48 N, 130.77 W
Elevation: 3940 feet (1200 m)
Last Updated: November 2000


                                                                                    Photograph by B. Edwards

Lava Fork volcano, which is probably the youngest volcano in Canada, is a small cinder pile on top of a remote mountain ridge in the Coast Mountains of British Columbia. The volcano's vent, shown above, is a pile of loose ash, lapilli-sized tephra and volcanic bombs. Lava Fork is the southernmost of ten volcanoes in the Iskut volcanic field, which includes volcanoes at Hoodoo Mountain and Iskut River. All volcanoes in the Iskut volcanic field are part of the northern Cordilleran volcanic province (Edwards & Russell 2000).
 


                                                                                    Photograph by B. Edwards

The valley-filling lava flows (shown above) traveled south 5 km where they crossed the border into Alaska and dammed the Blue River, forming several small lakes. In total the lava flows are approximately 22 km long.
 


                                                                                  Photograph by B. Edwards

The surface of the lava flows still have well-preserved flow features (pressure ridges and lava channels), pits formed when the overlying solidified lava collapsed into underlying lava tubes, and tree molds (seen in the picture above). Also seen in the picture above, locally large trees are embedded in the top of the lava flows. Based on dating of tree-ring cores and radiometric ages from 14C dating, the youngest of these lava flows is probably only 150 years old (Hauksdottir et al., 1994).
 

-summary by Ben Edwards, Grand Valley State University, MI



Sources of Information:

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., and 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.

Russell, J.K. & Hauksdottir, S. 2000. Estimates of crustal assimilation in Quaternary lavas from the northern cordillera, British Columbia.
Canadian Mineralogist, 39, 361-383.

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.


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