SURFICIAL GEOLOGY OF THE ST. FINTAN'S, LITTLE FRIARS COVE AND FLAT BAY MAP AREAS (NTS 12B/2, 12B/3 and 12B/7)

The surficial geology of southern St. George's Bay consists of a broad coastal plain covered by till inland and gravel closer to the coast. In the highland areas, a mix of bedrock, till veneers and patches of thicker till is found. Ice-flow mapping was through a combination of till fabric analysis and striation mapping. An early, coast parallel flow, possibly originating from outflow from the Stephenville area, deflected by ice in the Gulf of St. Lawrence, is identified. As ice retreated, ice-flow directions changed to be dominantly westward, from an ice cap centred over the adjacent Long Range Mountains. Although there is no conclusive evidence, erratics and striae found in the Anguille Mountains suggest that their summits were over-topped by ice. Further retreat led to topographic control of ice flow, with diversion of ice along the valley containing Codroy Pond. Deglaciation resulted in complex sedimentary sequences, now exposed at the coast, as the ice sheet grounded in the sea. Thick marine clays pose a geotechnical problem in construction. Such clays are highly susceptible to slope failure, as shown by large rotational slumps along the coast. The coast is eroding rapidly, and construction close to the current cliff edge should be avoided.