Distribution:

Ice Peak, Armadillo Peak and central plateau (Souther, 1988).

Lithology:

Unconsolidated, air-fall pumice of the Sheep Track Member of the Big Raven Formation blankets an area of about 40 km² on the southwest flank of Ice Peak and the adjacent plateau. The maximum clast size occurs along the western margin of Tencho Glacier where fracture-bounded pumice fragments are up to 10 cm across. Clasts become more rounded from the margins of the pile. The pumice has been largely removed from the drainage channels of small intermittent streams on the upper plateau but interfluvial areas are covered to depths of up to 2m. The Sheep Track pumice is a completely vitreous, aphyric froth of trachytic composition. Its source is unknown; probably hidden beneath Tencho Glacier. A deep, circular depression on the ice surface north of Coffee Crater may be an artifact of the Sheep Track eruption.

Relationship:

The Sheep Track Member is a unit of the Big Raven Formation (Mount Edziza Complex). It was deposited on all the Big Raven lava flows and cinder cones of the Snowshoe Lava Field except "The Saucer" which is covered by only thin drifts of wind-blown pumice (Souther, 1992).

History:

Initially appeared as the Sheep Track Formation in Souther et al. (1984).

Other Citations:

Mihalynuk et al., 1996.

References:

Mihalynuk, M., Bellefontaine, K., Brown, D., Logan, J., Nelson, J., Legun, A. and Diakow, L., 1996. Digital Geology, NW British Columbia (94/E, L, M; 104/F, G, H, I, J, K, L, M, N, O, P; 114/I, O, P); Ministry of Energy, Mines and Petroleum Resources, Open File 1996-11.

Souther, J.G., 1988. Geology, Mount Edziza volcanic complex, British Columbia; Geological Survey of Canada, "A" Series Map no. 1623A, 2 sheets.

Souther, J.G., 1992. The Late Cenozoic Mount Edziza Volcanic Complex, British Columbia; Geological Survey of Canada, Memoir 420, 329 p.

Souther, J.G., Armstrong, R.L., and Harakal, J., 1984. Chronology of the peralkaline, late Cenozoic Mount Edziza Volcanic Complex, northern British Columbia, Canada; Geological Society of America Bulletin, March 1984, Vol. 95, Issue 3, pp. 337-349.