72 Paleoindian Western North America: Climate and Life at the Last Glacial Termination (Posters)

THE ENVIRONMENT OF LATE PLEISTOCENE - EARLY HOLOCENE QUEEN CHARLOTTE ISLANDS ARCHIPELAGO, WESTERN CANADA AND IMPLICATIONS FOR EARLY HUMANS

Paper number: 72-2
Program: SYMPOSIA
Time: 1:30 PM – 4:30 PM

Authors

Abstract

Paleogeographical and paleoenvironmental reconstructions identify a complex glacio-isostatic and sea level history along Canada’s northeast Pacific margin during and subsequent to the last glacial maximum (LGM). An estimated 690 m of glacial ice began retreating from Dixon Entrance after 14.5 and before 12.6 ka BP. Prior to this time navigation along northern Queen Charlotte Islands (QCI) and Dixon Entrance was precluded due to the presence of ice; early migrants would have skirted outer QCI or traveled over land (ice). Lowered eustatic sea level combined with crustal uplift permitted terrestrial conditions to develop on two emergent coastal plains. The northern plain was present from ~14.0 to at least 9.1 ka BP. The southern plain remained until as late as 7.8 ka BP. Northern Hecate Strait closed by ~11.7 ka BP creating a landbridge that connected the British Columbia (BC) mainland and the QCI, facilitating faunal, floral, and potential land-based human migration.

By at least 13.2 ka BP productive estuaries, quiet water bays, and deltas were home to many edible intertidal molluscs, indicating the region had a suitable climate not only for them, but for early human inhabitants as well. Numerous resource-rich coastal zones and estuaries in Hecate Strait and QC Sound have been cored and dated and although these would make excellent potential early archaeological site locations, they are now drowned and difficult to access. Paleocoastlines obtained by overlaying paleogeographic reconstructions over present-day subaerial topography outline the location of potential early archaeological sites. Paleocoastlines of particular archaeological interest lie along the west coast of QCI, where early migrators likely first traveled and westernmost sites along the BC mainland.

Reduced coastal zone productivity during a cooler “Younger Dryas” interval between ~10.9 and 10.2 ka BP potentially altered migration and habitat conditions, forcing early peoples to migrate greater distances to collect coastal resources and/or increase their reliance on land-based resources. By at least 9.0 ka BP the currently turbulent outer coast region was highly productive and by ~8.9 ka BP edible molluscan biomass densities were within viable commercial harvest levels in southern Moresby Island.