Photograph by B. Edwards
Photograph by B. Edwards
The Nisga’a Memorial Lava Beds Provincial Park, a park designed largely around lava flows from the Tseax River cones, is ~60 km north of Terrace, British Columbia and is centered around cinder cones and the accompanying lava flows of the Aiyansh/Tseax River volcano. The photograph above shows a tumulus in the middle of the broad lava plain that formed in the Nass River valley during the eruptions. The cinder cones are situated in a valley above and east of the Tseax River, ~20 km south of the river’s junction with the larger Nass River. The most recent cone, 290 m in diameter at the base, rests on the remains of an earlier and somewhat larger, dissected 460 m diameter cone. The cones formed in the narrow confines of a tributary of the Tseax River and comprise basaltic bombs and cinder. The most recent lava flowed 22.5 km from the vent to the Nass River where, according to legend of the Nisga'a First Nations people, it blocked the flow of the Nass River. Along the south edge of the Nass River, the exposed lava contains structures indicative of lava that has flowed over wet ground. The provincial park is a must for volcano enthusiasts because it is easily accessible and a wide range of lava flow morphologies can be viewed within the park, including pahoehoe and aa lava flow morphologies. Tseax cone is the southermost volcano in 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, Canada.
Geological Society of America Bulletin, 112, 1280-1295.
Sutherland Brown, A. 1969. Aiyansh lava flow, British Columbia. Canadian
Journal of Earth Sciences,
v. 6, p. 1460-68.
Symons, D.T.A. 1975. Age and flow direction from magnetic measurements
on the Historic Aiyansh flow,
British Columbia. Journal of Geophysical Research, v. 80, p. 2622-26.Wuorinen,
V. 1978. Age of Aiyansh
volcano, British Columbia. Canadian Journal of Earth Sciences, v. 15,
p. 1037-1038.
