The Shield Archaic tradition occupied the northern boreal forest and tundra during the “Climatic Optimum” or Hypsithermal, beginning about 6500 years ago. Indian sites are as widespread in this warm period as Pre-Dorset sites were in the preceding cold period. Shield Archaic tundra sites are divided into Early, Middle and Late phases using point change and 11 dates as a criterion for their evolution. The 5450-6,450 year-old Early phase is associated only with a small notched point from KjNb-7 at Warden’s Grove. The 4450-5450 year-old Middle phase has eight dates, five from KkLn-4 (Migod) at Grant Lake and three from Warden’s Grove sites. The 3500-4450 year-old Late phase is dated from as far north as Aberdeen and Grant Lakes, as far south as Whitefish Lake and southeast into Manitoba. A 4040 year-old date (S-1435) from level 5 at Whitefish Lake is associated with a Plains Archaic McKean-Duncan point.

Several Shield Archaic tundra sites are at Hornby-Lookout Points, Ursus Island-Thelon Bluffs and Grant and Beverly-Aberdeen Lakes. Site clusters, which at that time were forested, resemble later site clusters when the area, along with the middle Dubawnt River, became tundra in Pre-Dorset; e.g., Warden’s Grove, Eyeberry Lake and Grassy Island on the Thelon River. Remote forest sites are at Thanakoie Narrows, Artillery Lake, and Boyd Lake on the upper Dubawnt River, and Black and Athabasca Lakes and Pipestone River in Saskatchewan.

Shield Archaic sites were used much longer seasonally than later traditions when forest extended north under a postglacial 4 deg. C rise in spring and 1 deg. at other times (Foley et al. 1994). Sphagnum peaks along with spruce and other pollen support a mean July temperature 4 deg. higher than present, with trees 120 km northwest of Grant Lake 5-6000 years ago (Terasmae and Craig 1958). Forest advance from Ennadai to Dubawnt Lakes (Nichols 1967a) is verified by 5000 year-old spruce micro-fossils in upper Thelon River sites (Mott, pers. comm., 1975). Rowe (1972), Larsen (1974) and Nichols’ (1976) treeline applies to both Shield Archaic and Plano traditions, but summers were warmest 4800-5200 years ago in the Middle Shield Archaic phase and 3800-4000 years ago in Late phase (Nichols 1976a, 1976b), periods of maximum Shield Archaic expansion. As higher rainfall in this period was balanced by evaporation, river runoff resembled that of today, as seen in Migod’s three Shield Archaic strata which are less than a meter above the Dubawnt River (Gordon 1976).

All Barrenland peoples hunted caribou during their late summer and early autumn migration, but Shield Archaic peoples profitted from expanding forest to push their hunting and habitation into areas that became tundra in Pre-Dorset. They were able to hunt at open river-crossings in spring because higher temperatures brought earlier break-up. Indeed, examination of caribou teeth increments from a jaw associated with the oldest Shield Archaic radiocarbon date (KjNb-7) reveal a May kill (Gordon 1985). Likewise, a later autumn extended hunting at water crossings well into autumn, and shortened winter south of the Hypsithermal treeline. Later cultures, and especially Pre-Dorset, had to master long range tundra hunting to approach the caribou calving ground.

from Gordon 1996. People of Sunlight; People of Starlight: Barrenland Archaeology in the Northwest Territories of Canada.Archaeological Survey of Canada, Mercury Series Paper 154. Canadian Museum of Civilization, pp.199-200.