PALEOENVIRONMENTAL RECONSTRUCTION OF THE ALPENA-AMBERLEY RIDGE SUBMERGED LANDSCAPE DURING THE LAKE STANLEY LOWSTAND (CA. 8.4-9 KA CAL BP), LAKE HURON

The Great Lakes basin has high potential for submerged archaeological sites due to considerable water level changes during deglaciation and as a result of Holocene climate change. The Holocene period in the Great Lakes basin (ca. last 12,000 years) was marked by several phases of drier climate and low lake levels (lowstands) including major events between ca. 11,300-8,400 cal BP recorded in sediments in Lake Huron and Georgian Bay (Lake Hough and Lake Stanley lowstands). During the Lake Stanley phase water levels in the Lake Huron basin were up to 70-100 m below present and large areas of the lake bed were exposed terrestrial landscapes. In 2007 and 2008, a 300 meter-long series of boulders was discovered on the Alpena-Amberley Ridge in 30 m of water in Lake Huron during a side-scan sonar survey. The boulders, when mapped, resembled caribou drive lanes which are well-documented in the Arctic. During the Lake Stanley lowstand phase, the Ridge was a sub-aerially exposed causeway separating the lake into two basins, and the discovery of the potential drive lanes provides compelling albeit circumstantial evidence that the Ridge supported human habitation during the early Holocene. Little is known about the paleogeography and environment of the Ridge since there is limited sedimentation, and most lake-level and paleoenvironmental research in Lake Huron has focused on the more sediment loaded basins of the Georgian and Saginaw Bays. In 2011 and 2012, a total of sixty-seven core, sediment and rock samples were collected by divers and ponar sampler on an ROV. Thirty-six surface sediment grab samples and six short (10-25 cm) cores were obtained for analysis of microdebitage, microfossils, grain size, and organic content. Cores were sub-sampled at 2 cm intervals for analysis, lithofacies logged in detail and photographed. Preliminary paleoenvrionmental reconstructions based on results from these samples indicate that during the last Lake Stanley phase, the Ridge was a relatively stable landscape with sub-artic vegetation, small shallow ponds, sphagnum bogs, wetlands and rivers, and would have provided numerous potential resources for both caribou and pre-historic hunter-gathers.