Stratigraphical Studies on the Shoreline Displacement of Lake Superior

1975 ◽  
Vol 12 (2) ◽  
pp. 300-319 ◽  
Author(s):  
Matti Saarnisto
Keyword(s):  
Water Level ◽  
Lake Superior ◽  
Morphological Data ◽  
Glacial Lakes ◽  
Land Uplift ◽  
The North ◽  
History Of ◽  
Shoreline Displacement ◽  
Late Wisconsinan ◽  
Lake Minong

Shoreline displacement in the Lake Superior basin was followed, independently of morphological data, by studying sediments of small lake basins at different elevations in the vicinity of Sault Ste. Marie, Wawa, and Marathon, Ontario. Emergence of small lakes, resulting from water level changes in the main basin, is documented in bottom sediments, and can be dated by radiocarbon and pollen analyses. The new stratigraphical findings were correlated with the earlier established morphological shorelines, and thus the Late Wisconsinan and Holocene history of lake levels was worked out.High post-Main Algonquin glacial lakes formed the highest shorelines along the east shore from Sault Ste. Marie up to Alona Bay between approximately 11 000 and over 10 100 B.P. Contemporaneously a series of Post-Duluth glacial lakes occupied the western Superior basin, subsequent to Glacial Lake Duluth. As the ice retreated to the north shore at 9500 B.P., Lake Minong came into existence. Its level was apparently controlled by a threshold higher than the present at Sault Ste. Marie. The water level of Lake Superior fell to the low water Houghton stage by 8000 B.P. The transgression which resulted in the Nipissing Great Lakes reached the Superior basin about 7000 B.P. and culminated 5500 B.P. Land uplift on the east shore of Lake Superior was very rapid immediately after the deglaciation, followed by decreasing rates up to the present, and there are all indications that the process has been continuous.

A post-Lake Minong transgressive event on the north shore of Lake Superior, Ontario: possible evidence of Lake Agassiz inflow

1994 ◽  
Vol 31 (11) ◽  
pp. 1638-1641 ◽  
Author(s):  
Brian A. M. Phillips ◽  
Philip W. Fralick
Keyword(s):  
Water Level ◽  
Lake Superior ◽  
Lower Portion ◽  
Fluvial Sediments ◽  
Lake Agassiz ◽  
North Shore ◽  
The North ◽  
Level Oscillation ◽  
Water Level Oscillation ◽  
Lake Minong

Modification of an ice-contact delta built on the margin of Lake Minong (9500 BP) is ascribed to a transgressive event. Reworking of fluvial sediments by wave action and the infilling of the lower end of a distributary valley demonstrate a post-Minong transgression and reoccupation of the lower portion of the delta. Estimated to be in the order of 18 m, this water-level oscillation may represent evidence of one of several catastrophic discharges of Lake Agassiz into the Superior basin, proposed to have occurred between 9.5 and 8.0 ka BP.

Late Wisconsinan and Holocene history of southwestern Saskatchewan

1994 ◽  
Vol 31 (12) ◽  
pp. 1822-1837 ◽  
Author(s):  
Rudy W. Klassen
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Lakes ◽  
Grassland Vegetation ◽  
Southern Limit ◽  
Northern Margin ◽  
The North ◽  
Proglacial Lakes ◽  
History Of ◽  
Late Wisconsinan

The Late Wisconsinan Laurentide Ice Sheet reached the limit of glaciation along the north-facing slope of the unglaciated part of the Cypress Hills nunatak, but elsewhere around the Cypress Hills and Wood Mountain uplands of southwestern Saskatchewan it did not reach the limit of glaciation. An interval of deglaciation was followed by a readvance of the ice sheet, about 15 ka, to a position near the Late Wisconsinan limit, and was marked by strong flow of Keewatin ice from the north and weaker flow of Hudson ice from the northeast. Final deglaciation resulted in the formation of glacial lakes around the Cypress Hills nunatak. A network of ice-marginal and subglacial trenches, presently occupied by the Frenchman Valley and its tributaries, was formed when these lakes drained along, over, and under ice towards the western part of the Wood Mountain Upland to the east. The main trench joined an ancestral part of Frenchman Valley along the ice-free southern slopes of Wood Mountain Upland. Meltwater from the ice bordering the northern margin of the upland drained southward, excavating trenches across the highest parts of the upland and deepening ancestral valleys across the southern slopes. A succession of proglacial lakes fronted parts of the ice margin as it retreated downslope to the north. The area was deglaciated about 13.5 ka. The southern limit of a north to south forest–grassland transition was established by 13 ka along the regional drainage divide across the study area. Prairie grassland vegetation covered the southern slopes of the uplands and forests of deciduous and coniferous trees covered the highest parts of uplands and drift-mantled parts of the continental glacier to the north. The belt of forest–grassland transition had shifted well to the north of the study area by 9 ka, and a climate that was warmer and drier than at present continued to about 5 ka, when conditions became somewhat cooler.

Water in the Wilderness: The Group of Seven and the Coastal Identity of Lake Superior

2021 ◽  
pp. e20200049
Author(s):  
Isabelle Gapp
Keyword(s):  
Environmental History ◽  
Lake Superior ◽  
Indigenous Communities ◽  
Coastal Lake ◽  
Group Of Seven ◽  
North Shore ◽  
The North ◽  
The People ◽  
Coastal Landscapes ◽  
History Of

This paper challenges the wilderness ideology with which the Group of Seven’s coastal landscapes of the north shore of Lake Superior are often associated. Focusing my analysis around key works by Lawren Harris, A.Y. Jackson, J.E.H. MacDonald, and Franklin Carmichael, I offer an alternative perspective on commonly-adopted national and wilderness narratives, and instead consider these works in line with an emergent ecocritical consciousness. While a conversation about wilderness in relation to the Group of Seven often ignores the colonial history and Indigenous communities that previously inhabited coastal Lake Superior, this paper identifies these within a discussion of the environmental history of the region. That the environment of the north shore of Lake Superior was a primordial space waiting to be discovered and conquered only seeks to ratify the landscape as a colonial space. Instead, by engaging with the ecological complexities and environmental aesthetics of Lake Superior and its surrounding shoreline, I challenge this colonial and ideological construct of the wilderness, accounting for the prevailing fur trade, fishing, and lumber industries that dominated during the nineteenth and early twentieth centuries. A discussion of environmental history and landscape painting further allows for a consideration of both the exploitation and preservation of nature over the course of the twentieth century, and looks beyond the theosophical and mystical in relation to the Group’s Lake Superior works. As such, the timeliness of an ecocritical perspective on the Group of Seven’s landscapes represents an opportunity to consider how we might recontextualize these paintings in a time of unprecedented anthropogenic climate change, while recognizing the people and history to whom this land traditionally belongs.

A Sault-outlet-referenced mid- to late-Holocene paleohydrograph for Lake Superior constructed from strandplains of beach ridges

2012 ◽  
Vol 49 (11) ◽  
pp. 1263-1279 ◽  
Author(s):  
John W. Johnston ◽  
Erin P. Argyilan ◽  
Todd A. Thompson ◽  
Steve J. Baedke ◽  
Kenneth Lepper ◽  
...  
Keyword(s):  
Water Level ◽  
Linear Trend ◽  
Lake Superior ◽  
Optically Stimulated Luminescence ◽  
Glacial Isostatic Adjustment ◽  
Beach Ridges ◽  
The Past ◽  
Isostatic Adjustment ◽  
History Of ◽  
Past Millennium

The most detailed Lake Superior paleohydrograph relative to the current outlet near Sault Ste. Marie, Ontario–Michigan, was constructed from four strandplains of beach ridges. This provides a history of water-level, glacial isostatic adjustment (GIA), and the active outlet prior to monitoring and regulation. Four relative paleohydrographs that are offset and subparallel owing to differences in GIA were produced from 321 basal foreshore elevations and 56 optically stimulated luminescence ages. Subtracting modeled elevations in defined millennial lake phases between relative paleohydrographs and similarity between an inferred Sault Ste. Marie (hereinafter, Sault) paleohydrograph and data near the zero isobase corroborates rates of GIA derived from water-level gauges. A change in trend in the Sault paleohydrograph is related to the final separation of Lake Superior from Lakes Michigan and Huron and is the youngest age reported at 1060 ± 100 years. A near-horizontal trend in the Sault paleohydrograph for the past millennium has an intercept that is close to the historical average for Lake Superior. A consistently linear trend from about 2 to 1 ka suggests a relatively stable outlet similar to the past millennium, but a decreasing trend from 3 to 1 ka suggests an outlet other than the Sault. Although intercept data beyond the last millennium are similar in elevation to the reported bedrock sill near Chicago (Hansel et al. 1985), we argue that the Port–Huron outlet was the active outlet during this time and the inferred paleohydrograph of Baedke and Thompson (2000) requires reevaluation.

scholarly journals The tribe Scrophularieae (Scrophulariaceae): A Review of Phylogenetic Studies

Hacquetia ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 337-347 ◽  
Author(s):  
Mehrshid Riahi ◽  
Farrokh Ghahremaninejad
Keyword(s):  
Phylogenetic Relationships ◽  
Molecular Data ◽  
Morphological Data ◽  
Hybrid Speciation ◽  
The North ◽  
Phylogenetic Studies ◽  
Phylogenetic Reconstructions ◽  
Data Collection And Analysis ◽  
History Of ◽  
Review Reports

Abstract Molecular data have been increasingly used to study the phylogenetic relationships among many taxa, including scrophs. Sometimes they have provided phylogenetic reconstructions that are in conflict with morphological data leading to a re-evaluation of long-standing evolutionary hypotheses. In this paper, we review reports of the recent knowledge of the phylogenetic relationships within Scrophularieae (2011–2017). The results of these analyses led to the following conclusions. (1) Species of Scrophularia have undergone one or more Miocene migration events occurred from eastern Asia to the North America with subsequent long dispersal and diversification in three main directions. (2) Allopolyploid and aneuploid hybrid speciation between Scrophularia species can occur, so hybridization and polyploidy have an important role for history of diversification. (3) The ancestral staminode type for the genus Scrophularia seems to be a large staminode. (4) Monophyly of the genus Verbascum with respect to the genus Scrophularia is strongly supported. (5) Oreosolen, is not monophyletic, because all accessions of Oreosolen were nested within Scrophularia. We discuss methods of data collection and analysis, and we describe the areas of conflict and agreement between molecular phylogenies.

scholarly journals Mine Flooding History of a Regional Below-Drainage Coalfield Dominated by Barrier Leakage (1970–2014)

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Joseph J. Donovan ◽  
Eric F. Perry
Keyword(s):  
Water Level ◽  
Mine Water ◽  
Underground Mines ◽  
Water Level Fluctuations ◽  
Water Control ◽  
Near Surface ◽  
The North ◽  
Mining History ◽  
History Of ◽  
Mine Flooding

A 44-year record of water level fluctuations in a series of adjacent closed underground mines documents the history of closure and mine flooding in the Fairmont Coalfield, one of the oldest coal mining districts in the Pittsburgh coal basin, West Virginia, USA. As closures proceeded and mines began to flood, US environmental regulations were first enacted mandating mine water control and treatment, rendering uncontrolled surface discharges unacceptable. The purpose of this study is to present this flooding history and to identify critical events that determined how mine pools evolved in this case. Also examined is the strategy developed to control and treat water from these mines. Flooding is visualized using both water level hydrographs and mine flooding maps with the latter constructed assuming mine water hydraulic continuity between one or more mines. The earliest flooding formed small pools within near-surface mines closed prior to 1962 yet still pumped following closure to minimize leaking into adjacent still-active workings. These subpools gradually enlarged and merged as more closures occurred and the need for protective pumping was removed, forming what is today referred to as the unconfined Fairmont Pool. Later, deeper mines, separated by intact updip barriers from the Fairmont Pool, were closed and flooded more gradually, supplied in large part by leakage from the Fairmont Pool. By 1985, all mines except 2 had closed and by 1994 all had fully flooded, with the Fairmont Pool interconnected to deeper single mine pools via barrier leakage. As protective pumping ceased, the Fairmont Pool rose to a water level 3 m higher than surface drainage elevation and in 1997 discharged from an undermined section of Buffalo Creek near the Monongahela River. The principal mine operator in the basin then designed a pumping system to transfer water from the Fairmont Pool to their existing treatment facilities to the north, thus terminating the discharge. It may be concluded that the progress of mine flooding was influenced by mining history and design, by the timing of closures, by barrier leakage conditions, and by geologic structure. A key element in how flooding proceeded was the presence of a series of intact barriers separating deep from shallow mines. The shallow mines closed and flooded early, but then lost sufficient water by barrier leakage into the deeper mines to delay the completion of flooding until after the deep mines had all closed and flooded as well. Intensive mine water control has continued from the 1997 breakout to the present. The final water control scheme was likely unanticipated and serendipitous; future district-wide mining efforts should be advised to consider in advance closeout strategies to control mine water postmining.

Glacial history of Northeastern Ontario II. The Timiskaming–Algoma area

1968 ◽  
Vol 5 (1) ◽  
pp. 97-109 ◽  
Author(s):  
A. N. Boissonneau
Keyword(s):  
Lake Superior ◽  
Great Lakes Basin ◽  
Upper Peninsula ◽  
North Shore ◽  
The North ◽  
Sequence Of Events ◽  
Glacial Chronology ◽  
History Of ◽  
Surficial Deposits ◽  
Upper Peninsula Of Michigan

The surficial deposits, ice movements, and glacial lakes within an area of 34 500 square miles in northeastern Ontario are described. Some of the moraines of the study are tentatively correlated with moraines to the west in the upper peninsula of Michigan, in the Nipigon area, and along the north shore of Lake Superior. The glaciolacustrine deposits and sequence of events in the study area in relation to the glacial features and chronology of the southern Great Lakes basin provide a basis for a partial glacial chronology for the study area. A knowledge of the glacial features of this area further elucidates the integration of movements of two advancing ice lobes, which was observed in northwestern Quebec.

GLACIAL FEATURES OF THE NORTH-CENTRAL LAKE SUPERIOR REGION, ONTARIO

1967 ◽  
Vol 4 (3) ◽  
pp. 515-528 ◽  
Author(s):  
S. C. Zoltai
Keyword(s):  
Lake Superior ◽  
Field Work ◽  
Aerial Photographs ◽  
Northern Ontario ◽  
Radiocarbon Dates ◽  
North Central ◽  
The North ◽  
Glacier Ice ◽  
History Of ◽  
Differential Uplift

The surficial glacial features and glacial events of a 13 000 square mile area in northern Ontario are described, based on field work and study of aerial photographs. Ice-laid and glaciolacustrine materials suggest a complex history of stationary ice fronts and glacial lakes during deglaciation. Lakes in the Lake Nipigon and Lake Superior basins inundated large areas. Post-Minong lake stages in the Superior basin intruded far to the north, dammed by ice at the largest moraine, the Nakina. The northern part of this lake was later separated from the post-Minong lake by differential uplift and was named Lake Nakina. After the withdrawal of the ice, Glacial Lake Barlow–Ojibway occupied the northeastern part of the area, and much of it was later overridden by the last glacial readvance. Stratigraphic correlations with radiocarbon dates suggest that the Nakina moraine was built some 9 400 years ago, and that the last glacier ice disappeared before 6 390 years ago.

GEOGRAPHIC DISTRIBUTION AND BIOGEOGRAPHY OF REPRESENTATIVE SPECIES OF XERIC GRASSLAND-ADAPTED NEARCTIC LYGAEIDAE IN WESTERN NORTH AMERICA (INSECTA: HETEROPTERA)

1993 ◽  
Vol 125 (S165) ◽  
pp. 75-113 ◽  
Author(s):  
G.G.E. Scudder
Keyword(s):  
North America ◽  
Geographic Distribution ◽  
Restriction Site ◽  
Sequence Data ◽  
The North ◽  
Representative Species ◽  
History Of ◽  
Dna Restriction ◽  
Present Distribution ◽  
Late Wisconsinan

AbstractThis paper outlines the known distribution of eight xeric grassland-adapted species of Lygaeidae, and examines these distributions with respect to the glacial history of North America during the Pleistocene, and past and present distribution of grassland vegetation. Four of these species (Neosuris castanea, Sisamnes claviger, Ligyrocoris latimarginatus, and Melanopleurus perplexus) probably survived the Pleistocene in refugia south of the Late Wisconsinan ice sheet. Differences in climatic requirements may explain the variations in geographic distribution exhibited by these four insects and a methodology for testing this is discussed. The four other species (Crophius ramosus, Kolenetrus plenus, Slaterobius insignis, and Emblethis vicarius) may have occurred in the north prior to 1.2 mya and survived the Late Pleistocene in both the northern Beringian refugium and in southern refugia. Molecular systematics, especially use of DNA restriction site or sequence data, might provide the evidence needed to test historical biogeographic postulates based on the extant distribution of these species.

Dating thermal anomalies in sedimentary basins: the diagenetic history of clay minerals in the Triassic sandstones of the Paris Basin, France

Clay Minerals ◽  
1992 ◽  
Vol 27 (2) ◽  
pp. 211-226 ◽  
Author(s):  
J. R. Mossmann ◽  
N. Clauer ◽  
N. Liewig
Keyword(s):  
Clay Minerals ◽  
North Atlantic Ocean ◽  
Sedimentary Basins ◽  
Morphological Data ◽  
Burial Depth ◽  
Paris Basin ◽  
Hydrothermal Conditions ◽  
Thermal Anomalies ◽  
The North ◽  
History Of

AbstractRhaetian (Upper Triassic) sandy horizons were sampled from the Paris Basin from SW to NE, crosscutting the Rhaetian at different depths from outcrop in the NE to 2700 m in the centre of the basin. The smallest day sub-fractions (<0·2 μm) from the deepest samples consist mainly of illite and chlorite having a K-Ar age of 〜190 Ma. Both minerals probably formed under specific hydrothermal conditions at high temperature, but at a burial depth of only 500 m. This thermal event could represent an echo of the "crustal" breakdown of the Northwestern European craton during the opening of the North Atlantic Ocean. Two other generations of illite-smectite mixed-layers formed in the same Rhaetian horizons at somewhat lower temperatures about 150 and 80 Ma ago. The three generations of clay minerals could be characterized and dated because of combined mineralogical, crystallographical and morphological data supporting the dating attempts.

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