GEOLOGY OF THE MOUNT GARIBALDI MAP-AREA, SOUTHWESTERN BRITISH COLUMBIA, CANADA PART II: GEOMORPHOLOGY AND QUATERNARY VOLCANIC ROCKS
The Mount Garibaldi map-area is in the southern Coast Mountains of British Columbia. The bold topography of the area is a product of two cycles of stream erosion modified by continental and alpine glaciation and by Quaternary vulcanism. The volcanic rocks of the map-area are lavas and pyroclastic rocks which postdate the second cycle of stream erosion; most if not all are Pleistocene, and many appear to have been erupted during periods of glaciation. Many of the anomalous structures can be attributed to deposition of lava or pyroclastic debris against, beneath, or onto glacial ice. Extrusive rocks range in composition from basalt to dacite; the latter are most voluminous.