Ocean Drilling Program Leg 169S: surficial geology, stratigraphy and geomorphology of the Saanich Inlet area, southeastern Vancouver Island, British Columbia

This paper provides: (i) a descriptive overview of the late Pleistocene and Holocene geology and geomorphology of the region surrounding Saanich Inlet ; and (ii) the palaeogeographic setting for discussion of the oceanographic record at ODP leg 169S sites 1033 and 1034. The dominant deposits and land forms in the Saanich Inlet area are similar to those of late Pleistocene ma rine-influenced glacial environments and modem fjord inlets dominated by re treating tide-water glaciers. Patterns of ice retreat, meltwater drainage a nd sea-level change are reconstructed for the interval 4000-15 000 calendar years before present (yrBP). The flux of meltwater and sediment into Saani ch Inlet was greatest between ca. 12 000 and 15 000 yrBP. At that time, sea level was up to 90 m higher relative to land than today. During deglaciati on, tidewater glaciers occupying Chemainus, Cowichan and Koksilah valleys e ntered a marine embayment that formed in the vicinity of Cowichan Bay, Sate llite Channel, Saanich Met and Saanich Peninsula. In the early Holocene, re lative sea level fell to a low stand perhaps tens of metres below the prese nt datum, and the surface area of Saanich Inlet and Satellite Channel was m uch reduced. By the middle Holocene, sea level had risen to near its presen t position, and modem drainage patterns and oceanographic conditions were e stablished. (C) 2001 Elsevier Science B.V. All rights reserved.