| dc.description.abstract | A geoarchaeological investigation was north of Highway 11/17, 34km east
of Thunder Bay, Ontario. Five archaeological sites (Mackenzie 1, Mackenzie 2,
RLF, Woodpecker 1, and Woodpecker 2) and seven additional sediment
exposures were examined for stratigraphic analysis to accompany the
archaeological excavations. River-mouth sediments at 268m asl and a series of
deltas indicate that the study area was subaqueous while placement of the
Superior lobe prevented drainage to the Superior basin. This elevation is
consistent with Lake Beaver Bay, an ice-contact lake that received glacial
meltwater from the north (the Hudson Bay lobe) as well as the south (the
Superior lobe). This is demonstrated by southward and northward prograding
deltaic sequences within the study area.
As the Superior lobe made its final retreat, Lake Beaver Bay dissipated
into the Superior basin marking the beginning of the Minong phase, likely around
9,900 14C yrs BP. Additional sequences representing river-mouth, beach
shoreface, and deltaic depositional environments indicate that a series of
shorelines within the study area represent subsequent Minong lake levels. The
highest, and likely oldest of these strandlines is an erosional feature at 256m asl,
consistent with wave-cut terraces previously identified in the Thunder Bay region.
Relative lake level drops occurred, likely due to a combination of gradual
erosion of the Nadoway Point sill and isostatic rebound of the recently
deglaciated land. Beach and river-mouth sequences representing subsequent
shorelines are located at 249m, 243m, and 240m asl. Artifacts on each of these
beach terraces suggest they were occupied by Paleoindian groups. | en_US |
