Tennena Cone

The cone is almost completely surrounded by Mount Edziza's ice cap and is one of several volcanoes in the Snowshoe Lava Field on the Big Raven Plateau.

Tennena Cone is part of the Mount Edziza volcanic complex, a group of overlapping volcanoes that have formed over the last 7.5 million years.

[2][6] In his 1992 report The Late Cenozoic Mount Edziza Volcanic Complex, British Columbia, Jack Souther gave Tennena Cone the numeronym SLF-1, SLF being an acronym for the Snowshoe Lava Field.

[6][17][18] The Big Raven Plateau is a major physiographic feature of the Mount Edziza volcanic complex, which consists of a group of overlapping shield volcanoes, stratovolcanoes, lava domes and cinder cones that have formed over the last 7.5 million years.

[22][23] Mount Edziza Provincial Park is in the Tahltan Highland, a southeast-trending upland area extending along the western side of the Stikine Plateau.

[23][24] Tennena Cone is part of the Northern Cordilleran Volcanic Province, a broad area of volcanoes and lava flows extending from northwestern British Columbia northwards through Yukon into easternmost Alaska.

[7][25] The dominant rocks comprising these volcanoes are alkali basalts and hawaiites, but nephelinite, basanite and peralkaline[a] phonolite, trachyte and comendite are locally abundant.

[38][39] Sheep Track pumice is lithologically distinct from the rest of the Big Raven Formation, consisting mainly of comenditic trachyte rather than alkali basalt or hawaiite.

[5][44] Lava flows from Tennena Cone travelled west through tunnels created by eruption-generated meltwater escaping at the base of the enclosing ice.

[44] The longest lava flow at the head of Sezill Creek valley 4.3 kilometres (2.7 miles) west of Tennena Cone travelled to the western edge of the enclosing ice, causing a violent steam explosion.

[4][6][46] Although the lava flow was quenched by meltwater throughout its entire length, it has a thickness of 2–4 metres (6.6–13.1 feet) and travelled into small depressions of the current topography.

[13] The exact age of Tennena Cone is unknown, but it may have formed during the Last Glacial Maximum between 23,000 and 18,000 years ago when the Mount Edziza volcanic complex was covered by the Cordilleran Ice Sheet.

[3][47] Another possibility is that the cone formed under an expansion of the Mount Edziza ice cap during the Younger Dryas between 12,900 and 11,600 years ago or during a more recent glacial advance.

[52] The degree of glacial erosion and the deposition of morainal detritus on the summit ridge of Tennena Cone suggest the volcano was overlain by significantly thick ice.

[53] Tennena Cone overlies the Armadillo, Ice Peak, Nido and Raspberry formations, all of which are older stratigraphic units of the Mount Edziza volcanic complex.

A black cone-shaped mountain rising over glacial ice and three climbers in the foreground
Glacier of Mount Edziza with the summit of Tennena Cone obscured by clouds in the background
Three climbers standing on a dark glacier with a black mountain in the right background
Glacier of Mount Edziza with the summit of Tennena Cone obscured by clouds in the right background