ABSTRACT: An examination of the morphology and petrology of the Ring Creek Lava Flow, south-West British Columbia.

CGRG Bibliography of Canadian Geomorphology
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Abstract

The Ring Creek lava flow is the youngest event in a series of Quaternary volcanic activity in Mount Garibaldi Volcano of south-west British Columbia, Canada, occurring between 10.7 – 9.3 ka. The lava flow erupted from parasitic Opal Cone and extends south 6.5 km before making a sharp turn and continues another 11.5 km. At this turn, the flow width reaches approximately 2.5 km. Examination of outcrops along the southern flow margin yield thickness estimates in excess of 200 m. The centre of the flow contains lava blocks up to 2 m in diameter, linear ridges parallel to flow direction ranging from 9 – 11 m in amplitude with a 26m peak to peak distance, and pressure ridges perpendicular to flow direction ranging from 4 – 13 m height with 21 – 35 m wavelength. Flow front breccia approximately 200 m in thickness is observed at the toe of the flow. The presence and magnitude of these features coupled with the mineral assemblage (pl+hbl+bt ± pyx ± mt) are typical of high viscosity flows. The Ring Creek lava flow is anomalous in that it was able to travel 18 km down-valley. This apparent contradiction is even more striking when compared to other flows on Mount Garibaldi with similar mineralogy, which are typically short thick flows or domes. This suggests that a factor other than viscosity has played an important role in determining the behaviour of the Ring Creek lava flow. Our investigation will address alternative governing factors of the Ring Creek flow, how they relate to other flows, and the implications of this anomalous activity for volcanic hazards.

Bibliography of Canadian Geomorphology