MASTODONS, THEIR GEOLOGIC AGE AND EXTINCTION IN ONTARIO, CANADA

1967 ◽  
Vol 4 (4) ◽  
pp. 663-675 ◽  
Author(s):  
A. Dreimanis
Keyword(s):  
Great Lakes ◽  
Ice Sheet ◽  
Late Glacial ◽  
Hardwood Forests ◽  
Radiocarbon Date ◽  
Southern Ontario ◽  
Spruce Forests

Most Canadian occurrences of mastodons are from southern Ontario. About four-fifths of them have been found below Lake Warren shore, thus being younger than 12 400 years B.P.; the youngest radiocarbon date is 8 910 ± 150 years B.P. Though most mastodons entered Ontario after the retreat of the Wisconsin ice sheet, a few occurrences may belong to the Mid- and Early Wisconsin interstadials. Association of spruce pollen with mastodon bones and concentration of mastodons in the poorly drained lacustrine plains during the late-glacial and early postglacial time suggest that mastodons preferred spruce forests or woodlands. The extinction of mastodons might have been initiated by gradual shrinking of these spruce forests, and completed by their disappearance from southwestern Ontario, owing to increasing warmth and dryness of postglacial climate, and improvement of drainage along the lowered Great Lakes. Mastodons did not find their way to the northern boreal spruce forests, being separated from them by a wide belt of pine and hardwood forests, which meanwhile had developed over the better drained morainic areas of southern Ontario. Weakened by less suitable food, mastodons became more sensitive to diseases and an easier prey to the Paleoindians.

scholarly journals Stratigraphic Architecture and Sediment Facies of the Western Oak Ridges Moraine, Humber River Watershed, Southern Ontario*

2006 ◽  
Vol 58 (2-3) ◽  
pp. 241-267 ◽  
Author(s):  
Hazen A.J. Russell ◽  
Robert W.C. Arnott ◽  
David R. Sharpe
Keyword(s):  
Ice Sheet ◽  
Lake Ontario ◽  
Late Glacial ◽  
Southern Ontario ◽  
Oak Ridges Moraine ◽  
River Watershed ◽  
Subglacial Lake ◽  
Humber River ◽  
Sand And Gravel ◽  
Subglacial Meltwater

Abstract The Oak Ridges Moraine in southern Ontario is a ca. 160 km long east-west trending ridge of sand and gravel situated north of Lake Ontario. Study of the Oak Ridges Moraine in the Humber River watershed was undertaken to assess its role in the groundwater system of the buried Laurentian Valley. The Oak Ridges Moraine is interpreted to have been deposited in three stages. Stage I records rapid deposition from hyperconcentrated flows where tunnel channels discharged into a subglacial lake in the Lake Ontario basin. Low-energy basin sedimentation of Stage II was in a subglacial and ice-contact setting of a highly crevassed ice sheet. Stage III sedimentation is characterized by rapid facies changes associated with esker, subaqueous fan, and basinal sedimentation. Detailed sediment analysis challenges the concept that the Oak Ridges Moraine was deposited principally from seasonal meltwater discharges, climatic modulated ice-marginal fluctuations, or in an interlobate position. Instead it is interpreted to have formed in response to late-glacial ice sheet events associated with subglacial meltwater ponding, episodic and catastrophic subglacial meltwater discharge, and subsequent seasonal meltwater discharge. The moraine probably formed as the glacial-hydraulic system re-equilibrated to the presence of a thinned, grounded ice shelf and a subglacial lake in the Lake Ontario basin.

Paleohydrology of the upper Laurentian Great Lakes from the late glacial to early Holocene

2009 ◽  
Vol 71 (3) ◽  
pp. 397-408 ◽  
Author(s):  
Andy Breckenridge ◽  
Thomas C. Johnson
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Lake Superior ◽  
Late Glacial ◽  
Lake Huron ◽  
Michigan Basin ◽  
Great Lakes Basin ◽  
Lake Agassiz ◽  
Sharp Drop ◽  
Freshwater Fluxes

AbstractBetween 10,500 and 9000 cal yr BP, δ18O values of benthic ostracodes within glaciolacustrine varves from Lake Superior range from − 18 to − 22‰ PDB. In contrast, coeval ostracode and bivalve records from the Lake Huron and Lake Michigan basins are characterized by extreme δ18O variations, ranging from values that reflect a source that is primarily glacial (∼ − 20‰ PDB) to much higher values characteristic of a regional meteoric source (∼ − 5‰ PDB). Re-evaluated age models for the Huron and Michigan records yield a more consistent δ18O stratigraphy. The striking feature of these records is a sharp drop in δ18O values between 9400 and 9000 cal yr BP. In the Huron basin, this low δ18O excursion was ascribed to the late Stanley lowstand, and in the Lake Michigan basin to Lake Agassiz flooding. Catastrophic flooding from Lake Agassiz is likely, but a second possibility is that the low δ18O excursion records the switching of overflow from the Lake Superior basin from an undocumented northern outlet back into the Great Lakes basin. Quantifying freshwater fluxes for this system remains difficult because the benthic ostracodes in the glaciolacustrine varves of Lake Superior and Lake Agassiz may not record the average δ18O value of surface water.

Late-glacial flow patterns, deglaciation, and postglacial emergence of south-central Baffin Island and the north-central coast of Hudson Strait, eastern Canadian Arctic

1996 ◽  
Vol 33 (11) ◽  
pp. 1499-1510 ◽  
Author(s):  
William F. Manley
Keyword(s):  
High Tide ◽  
Ice Sheet ◽  
Late Glacial ◽  
Flow Patterns ◽  
Sediment Provenance ◽  
Radiocarbon Dates ◽  
Ice Cap ◽  
The North ◽  
South Central ◽  
Ice Stream

New georaorphic, sedimentologic, and chronologic data are used to reconstruct late Quaternary ice-sheet flow patterns, deglaciation, and isostatic uplift along the largest marine trough connecting the Laurentide Ice Sheet with the North Atlantic Ocean. The Lake Harbour region was targeted for study given its potential to record flow from several ice-dispersal centers. Striations and sediment provenance indicators define flow patterns. Thirty-four radiocarbon dates constrain a chronology of events. Centuries or millennia(?) before deglaciation, a southeast-flowing ice stream impinged on southernmost Big Island, as recorded by a single striation site and delimited in extent by geomorphic evidence of cold-based ice. During the Cockburn Substagc (9000–8000 BP), the region was scoured by southward to southwestward flow from an ice cap on Meta Incognita Peninsula, as recorded by 60 striation sites along 200 km of coastline. Carbonate erratics are uncommon in till above the marine limit. Where present, they suggest that southward flow reworked older drift. At about 8200 BP, the area was dcglaciated, and the marine limit was established at elevations of 67–141 m above high tide. Iceberg calving and sediment discharge from an ice margin in Ungava Bay, Hudson Bay, or Foxe Basin then blanketed the area with limestone-rich glaciomarinc sediment. Afterward, the region experienced slow but sustained emergence. The data revise the maximum lateral extent of a Late Wisconsinan ice stream in Hudson Strait and emphasize the extent of a late-glacial ice cap on western Meta Incognita Peninsula.

scholarly journals Fish and maize: Bayesian mixing models of fourteenth- through seventeenth-century AD ancestral Wendat diets, Ontario, Canada

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Robert S. Feranec ◽  
John P. Hart
Keyword(s):  
Native American ◽  
Seventeenth Century ◽  
Great Lakes ◽  
Tooth Enamel ◽  
Mixing Models ◽  
Agricultural Systems ◽  
Southern Ontario ◽  
Bayesian Mixing Models ◽  
Freshwater Bodies ◽  
Dietary Mixing

Abstract Freshwater and marine fish have been important components of human diets for millennia. The Great Lakes of North America, their tributaries and smaller regional freshwater bodies are important Native American fisheries. The ethnohistorical record, zooarchaeological remains, and isotopic values on human bone and tooth collagen indicate the importance of fish in fourteenth- through seventeenth-century ancestral Wendat diets in southern Ontario, which is bordered by three of the Great Lakes. Maize (Zea mays ssp. mays) was the primary grain of Native American agricultural systems in the centuries prior to and following sustained European presence. Here we report new Bayesian dietary mixing models using previously published δ13C and δ15N values on ancestral Wendat bone and tooth collagen and tooth enamel. The results confirm previous estimates from δ13C values that ancestral Wendat diets included high proportions of maize but indicate much higher proportions of fish than has previously been recognized. The results also suggest that terrestrial animals contributed less to ancestral Wendat diets than is typically interpreted based on zooarchaeological records.

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