ABSTRACT: -Quaternary geology and till geochemistry of the Bonavista Peninsula.

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Surficial geology mapping and a regional till geochemistry survey were completed on the Bonavista Peninsula and areas to the west. Mapping involved the identification of landform and sediment types and included the measurement of paleo ice-flow indicators, as a means of reconstructing the areas' ice-flow history. Sampling of surface tills was at a density of 1 sample per 1 km (super 2) in areas of road access, to 1 sample per 4 km (super 2) in areas where helicopter support was required. A total of 1135 samples were collected during the survey. During the last glaciation, the Bonavista Peninsula was almost entirely covered by eastward-flowing ice, derived from an ice dispersal centre to the west of the study area, likely Middle Ridge. Glacier flow was drawn down into Goose Arm, Sweet Bay and Southern Bay and thence into Bonavista Bay, or through Smith Sound, Northwest Arm or Trinity Harbour into Trinity Bay. This drawdown effect was more pronounced as the ice began to thin and became topographically controlled during deglaciation. The Bonavista Peninsula, north of a line between Trinity and Plate Cove West, was covered by an independent ice centre. Ice flow from this latter centre was coastward from a northeast-southwest-trending ice divide that followed the height of land. Deglaciation was toward the major dispersal centres. The trend of esker ridges on the Tug Pond area shows westward retreat, likely toward the Middle Ridge area. Raised marine terraces are found at similar elevations around the peninsula (maximum 28 m asl), suggesting simultaneous retreat of ice and the accompanying marine incursion. The timing of deglaciation and the pattern of postglacial sea-level change are uncertain because of the paucity of dateable material.

Bibliography of Canadian Geomorphology