14
Some Unusual Relict Features in the Great
Lakes Coastal Zone
14.1 Introduction
With the exception of features in the modern surf and swash
zones, nearly all of the geomorphic features in the GLCZ are
relict, i.e., have survived from an earlier geologic period and
are being modified by current geomorphic and pedologic
processes. This chapter highlights some of the unusual relict
features from the earliest ancestral Great Lakes. These are
discussed under three categories, including (i) glacial and
periglacial, (ii) lacustrine and glaciolacustrine, and (iii) early
people.
14.2 Glacial and Periglacial
Following recession of the Laurentide glaciers from 13.6 to
ca. 9.5 ky ago, a periglacial climate existed throughout much
of the Great Lakes basin. This is evidenced not only by the
fossil pollen record, but also by landscape features attesting
to a subarctic climate. Solifluction lobes and sheets are types
of slope failure that are common in permafrost environments. Solifluction forms tongue-shaped features due to
differential downhill flow rates. Figure 14.1 shows relict
solifluction lobes at Ead’s Bush 3.6 km southwest of Little
Current on northern Manitoulin Island, Ontario. There are at
least four southeast-facing terraces with lobes at elevation
between 270 and 290 m (885 and 950 ft) on the upper
Glacial Lake Algonquin terraces. The individual lobes range
from 50 to 670 m (165–2,200 ft) in length, 70 to 90 m (230–
295 ft) in width, and 2 to 5 m (6.5–16 ft) in height. The
features are developed on the Farmington soil (Orthic
Melanic Brunisol; Typic Eutrudepts), which contains 30 cm
(12 in.) of calcareous till over dolomitic bedrock. The
solifluction lobes likely developed following the Main
Algonquin ca. 13.8–ca. 12.4 ka.
Relict patterned ground occurs in lowlands of the Great
Lakes, particularly in the Huron Basin (Morgan 1982; Gao
2005; Lusch et al. 2009). Figure 14.2 is a satellite image
showing relict flat-centered ice-wedge polygons near Highwood Glen, 25 km (15 mi) northeast of Sarnia, Ontario. The
polygons are 70–160 m across and the polygon fissures are
5–10 m across. According to Gao (2005; site 2), the polygons range from 1 to over 3 m (3–10 ft) in depth. Permafrost
existed in the area from ca. 13.8 to ca. 12.4 ka.
14.3 Glaciolacustrine and Lacustrine
Raised beaches are one of the more common geomorphic features in the GLCZ. Figure 14.3 shows a “staircase” of raised
beaches on Morphets Siding Road south of Little Current,
Ontario, on the shore of Georgian Bay (Lake Huron). Five of the
eight raised beaches listed in Table 14.1 are shown in the figure,
including the Korah (206 m), Sheguiandah (223 m), Payette
(240 m), Cedar Point (256 m), and the Penetang (271 m)
(Table 14.4). In addition to raised beaches, there are spits,
tombolos, beach ridges, sea stacks, cavettos, deltas, and dunes
distant from the present Great Lakes shoreline. Many of these
features represent Early Lake Algonquin or Iroquois shorelines
but some are from Lake Nipissing. Figure 14.4 shows a tombolo surrounded by uplifted beach ridges on the Point Isabella
Headland on the eastern shore of the Keweenaw Peninsula
(Lake Superior). The current shoreline of Lake Superior is at
183 m (601 ft). The raised beaches range from 186 to 202 m
(610–663 ft) and the tombolo is at 206 m (676 ft), all within the
limits of the former Nipissing shoreline.
© Springer Nature Switzerland AG 2021
J. G. Bockheim, Soils of the Laurentian Great Lakes, USA and Canada,
https://doi.org/10.1007/978-3-030-52425-8_14
149
Some Unusual Relict Features in the Great
Lakes Coastal Zone
14.1 Introduction
With the exception of features in the modern surf and swash
zones, nearly all of the geomorphic features in the GLCZ are
relict, i.e., have survived from an earlier geologic period and
are being modified by current geomorphic and pedologic
processes. This chapter highlights some of the unusual relict
features from the earliest ancestral Great Lakes. These are
discussed under three categories, including (i) glacial and
periglacial, (ii) lacustrine and glaciolacustrine, and (iii) early
people.
14.2 Glacial and Periglacial
Following recession of the Laurentide glaciers from 13.6 to
ca. 9.5 ky ago, a periglacial climate existed throughout much
of the Great Lakes basin. This is evidenced not only by the
fossil pollen record, but also by landscape features attesting
to a subarctic climate. Solifluction lobes and sheets are types
of slope failure that are common in permafrost environments. Solifluction forms tongue-shaped features due to
differential downhill flow rates. Figure 14.1 shows relict
solifluction lobes at Ead’s Bush 3.6 km southwest of Little
Current on northern Manitoulin Island, Ontario. There are at
least four southeast-facing terraces with lobes at elevation
between 270 and 290 m (885 and 950 ft) on the upper
Glacial Lake Algonquin terraces. The individual lobes range
from 50 to 670 m (165–2,200 ft) in length, 70 to 90 m (230–
295 ft) in width, and 2 to 5 m (6.5–16 ft) in height. The
features are developed on the Farmington soil (Orthic
Melanic Brunisol; Typic Eutrudepts), which contains 30 cm
(12 in.) of calcareous till over dolomitic bedrock. The
solifluction lobes likely developed following the Main
Algonquin ca. 13.8–ca. 12.4 ka.
Relict patterned ground occurs in lowlands of the Great
Lakes, particularly in the Huron Basin (Morgan 1982; Gao
2005; Lusch et al. 2009). Figure 14.2 is a satellite image
showing relict flat-centered ice-wedge polygons near Highwood Glen, 25 km (15 mi) northeast of Sarnia, Ontario. The
polygons are 70–160 m across and the polygon fissures are
5–10 m across. According to Gao (2005; site 2), the polygons range from 1 to over 3 m (3–10 ft) in depth. Permafrost
existed in the area from ca. 13.8 to ca. 12.4 ka.
14.3 Glaciolacustrine and Lacustrine
Raised beaches are one of the more common geomorphic features in the GLCZ. Figure 14.3 shows a “staircase” of raised
beaches on Morphets Siding Road south of Little Current,
Ontario, on the shore of Georgian Bay (Lake Huron). Five of the
eight raised beaches listed in Table 14.1 are shown in the figure,
including the Korah (206 m), Sheguiandah (223 m), Payette
(240 m), Cedar Point (256 m), and the Penetang (271 m)
(Table 14.4). In addition to raised beaches, there are spits,
tombolos, beach ridges, sea stacks, cavettos, deltas, and dunes
distant from the present Great Lakes shoreline. Many of these
features represent Early Lake Algonquin or Iroquois shorelines
but some are from Lake Nipissing. Figure 14.4 shows a tombolo surrounded by uplifted beach ridges on the Point Isabella
Headland on the eastern shore of the Keweenaw Peninsula
(Lake Superior). The current shoreline of Lake Superior is at
183 m (601 ft). The raised beaches range from 186 to 202 m
(610–663 ft) and the tombolo is at 206 m (676 ft), all within the
limits of the former Nipissing shoreline.
© Springer Nature Switzerland AG 2021
J. G. Bockheim, Soils of the Laurentian Great Lakes, USA and Canada,
https://doi.org/10.1007/978-3-030-52425-8_14
149