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.

The Deglaciation History of the Lake Superior Region and its Climatic Implications

1974 ◽  
Vol 4 (3) ◽  
pp. 316-339 ◽  
Author(s):  
Matti Saarnisto
Keyword(s):  
Lake Superior ◽  
Cold Climate ◽  
Northern Ontario ◽  
The North ◽  
Lake Algonquin ◽  
Western Lake ◽  
History Of ◽  
Ice Retreat ◽  
Main Lake ◽  
High Level

A zone of synchronous end moraines has been recognized in the Lake Superior region across northern Ontario and Michigan. The moraines were formed between 11,000 and 10,100 y.a. as cold climate resulted in successive halts in the general ice retreat. The cold climate is also indicated by the presence of tundra near Lake Superior until about 10,000 y.a. This episode is here referred to as the Algonquin Stadial. It was preceded and followed by rapid deglaciation. The Algonquin Stadial is comparable in age with the Younger Dryas Stadial of Europe, and indicates a reversal in the continuous trend toward a warmer climate during Late-Wisconsin (an) time. The apparent conflict between the present result (based on geologic evidence) and earlier pollen stratigraphical studies with no reversal is discussed.Glacial Lake Duluth formed in the western Lake Superior basin before 11,000 BP, followed by a series of Post-Duluth lakes between approximately 11,000 and over 10,100 BP. The Main Lake Algonquin stage in the Huron and Michigan basins terminated approximately 11,000 BP. The subsequent high-level post-Main Algonquin lakes, which were contemporaneous with the Post-Duluth lakes, existed in the southeastern Lake Superior basin. When the ice margin was along the north shore 9500 BP Lake Minong occupied the whole Lake Superior basin. By 9000 BP the ice had retreated north of Lake Superior-Hudson Bay divide.

Within-field Pathogenic Diversity of Phytophthora sojae in Commercial Soybean Fields in Iowa

2009 ◽  
Vol 10 (1) ◽  
pp. 8 ◽  
Author(s):  
Alison E. Robertson ◽  
Silvia R. Cianzio ◽  
Sarah M. Cerra ◽  
Richard O. Pope
Keyword(s):  
The United States ◽  
Phytophthora Sojae ◽  
Soil Samples ◽  
Soybean Plant ◽  
North Central Region ◽  
North Central ◽  
The North ◽  
History Of ◽  
The Many ◽  
Pathogenic Diversity

Phytophthora root and stem rot (PRR), caused by the oomycete Phytophthora sojae, is an economically important soybean disease in the north central region of the United States, including Iowa. Previous surveys of the pathogenic diversity of P. sojae in Iowa did not investigate whether multiple pathotypes of the pathogen existed in individual fields. Considering the many pathotypes of P. sojae that have been reported in Iowa, we hypothesized multiple pathotypes could exist within single fields. In the research reported herein, several soil samples were collected systematically from each of two commercial fields with a history of PRR in Iowa, and each soil sample was baited separately for isolates of P. sojae. Numerous pathotypes of P. sojae were detected from both fields. As many as four pathotypes were detected in some soil samples (each consisting of six to eight soil cores), which suggests that a single soybean plant could be subjected to infection by more than one pathotype. This possibility presents important implications in breeding resistant cultivars and in the management of PRR. Accepted for publication 14 July 2009. Published 8 September 2009.

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.

Alternate Strip Clearcutting in Upland Black Spruce: VIII. Shallow-soil Ecosystems and Their Classification

1988 ◽  
Vol 64 (1) ◽  
pp. 70-75 ◽  
Author(s):  
Richard A. Sims ◽  
William D. Towill
Keyword(s):  
Black Spruce ◽  
Mineral Soil ◽  
Fragile Sites ◽  
Soil Types ◽  
Northern Ontario ◽  
North Central ◽  
The North ◽  
Shallow Soil ◽  
Soil Ecosystems ◽  
Shallow Soils

Shallow-soil sites in the Nipigon-Beardmore area of northern Ontario are widespread and pose unique operational problems for forest managers. Several working definitions of shallow soils are used in Ontario. More accurate regional definitions are required in order that silvicultural decisions for these sometimes fragile sites may be refined or new ones developed. Harvesting and silvicultural options for shallow-soil sites are limited in the North Central Region.A program of Forest Ecosystem Classification (FEC) for the North Central Region has been designed to provide better understanding of shallow sites and a framework of standardized definitions. The FEC describes several shallow-soil types that occur over boulder pavement or bedrock, and differentiates mainly on the basis of depth-to-rock contact, surface organic material thickness and texture of the primary mineral soil particles. Operational application of this classification may require identification of complexes of shallow-soil types.

Exhumational history of the north central Pamir

Tectonics ◽  
2010 ◽  
Vol 29 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
William H. Amidon ◽  
Scott A. Hynek
Keyword(s):  
North Central ◽  
The North ◽  
History Of

Early Medieval Fortifications near Rome

1964 ◽  
Vol 32 (1) ◽  
pp. 89-122
Author(s):  
A. W. Lawrence
Keyword(s):  
Middle Ages ◽  
Local Development ◽  
Central Italy ◽  
Field Work ◽  
Relevant Information ◽  
North Central ◽  
The North ◽  
Key Sites ◽  
Natural Decay ◽  
Work Done

The few scholars who have specialised upon military architecture in Italy have, very naturally, concentrated their attention on the spectacular work of the thirteenth to the sixteenth centuries, chiefly in Apulia and Sicily, to a lesser extent in the North; Central Italy as a whole, has been neglected, and particularly the neighbourhood of Rome. There alone can the unimpressive fortresses of the early middle ages be seen in abundance, most of them untouched except by natural decay, because they were not rebuilt when their obsolescence became recognised, but abandoned—in a large number of instances, so documents imply, during the fourteenth century. This article is an attempt to trace the course of local development down to 1300, as shown mainly at certain key-sites. The argument rests on a basis of combined archaeological and documentary evidence; the former is limited by the amount of field-work done by my predecessors or by myself, the latter I have derived entirely from the regional historians of the past hundred years. Investigation of sites not yet reported, and of documents not yet searched for relevant information, should eventually lead to a more precise chronology than is now feasible.

I.—Belgic and Roman Silchester: the Excavations of 1954–8 with an Excursus on the Early History of Calleva

Archaeologia ◽  
1969 ◽  
Vol 102 ◽  
pp. 1-81 ◽  
Author(s):  
George C. Boon
Keyword(s):  
Field Work ◽  
Early History ◽  
Total Evidence ◽  
The South ◽  
Public And Private ◽  
Ordnance Survey ◽  
North West ◽  
The North ◽  
History Of

SummaryThe excavations were undertaken by the Silchester Excavation Committee supported by donations from public and private bodies and from individuals and by permission of the Duke of Wellington, K.G., F.S.A. Their purpose was the investigation of (a) a previously unsuspected polygonal enclosure of about 85 acres, here named the Inner Earthwork, which lay partly inside and partly outside the line of the familiar Roman town wall; and (b) a western extension to the known line of the Outer Earthwork, which increased the size of this enclosure from about 213 to 233 acres. With the assistance of the Ordnance Survey, the aerial traces of these earthworks, first observed and recorded by Dr. J. K. St. Joseph, F.S.A., were confirmed and extended by field-work and excavation, and have been planned as appears on pl. I.The excavations showed that the Inner Earthwork was a defence of Gaulish ‘Fécamp’ type, and that it was erected, on the south, over an area of late pre-Roman occupation, the first clearly identified at Calleva Atrebatum, but one with strong ‘Catuvellaunian’ influences in its pottery-series. It is claimed that the Inner Earthwork was constructed by the client King Cogidubnus in or shortly after A.D. 43–4, as the defence of this, the most important settlement in the north-west of his dominions. It is further suggested that the Inner Earthwork was replaced by the Outer Earthwork also during the reign of Cogidubnus.The excursus attempts to collate with the results of excavation the earlier discoveries of pre-Conquest material. The total evidence is finally related to the Belgico-Roman topography of Silchester and its neighbourhood, within the historical framework of the century and a half which separated the arrival of the earliest Belgic immigrants in the region from the death of Cogidubnus and the consequent emergence of the Roman Civitas Atrebatum.

Sedimentology and stratigraphy of the Cretaceous Virginian Ridge Formation, Methow Basin, Washington

1985 ◽  
Vol 22 (9) ◽  
pp. 1274-1285 ◽  
Author(s):  
James H. Trexler Jr.
Keyword(s):  
Upper Cretaceous ◽  
Western North America ◽  
The West ◽  
Detailed Model ◽  
North Central ◽  
North American Cordillera ◽  
The North ◽  
History Of ◽  
Tectonic Settings ◽  
Overlying Strata

The Cretaceous Methow Basin of north-central Washington is the southernmost of a series of Mesozoic successor basins in the Cordillera of western North America. The Albian–Campanian(?) Virginian Ridge Formation comprises three members, newly defined here, that gradationally interfinger with each other and grade laterally and upward into overlying strata. Detailed stratigraphic analysts of the Virginian Ridge Formation and of the intimately related parts of the Winthrop and Midnight Peak formations indicates that these units represent complexly interfingering facies derived from a variety of sources, both to the west and to the east of the basin and locally within the system. This study suggests a detailed model for the history of the Upper Cretaceous Methow Basin: generation of a restricted basin with a stable, roughly north–south-trending axis, filled by a stable, east-derived fluvial and deltaic system (Winthrop Formation) interfingering with a laterally amalgamated, west-derived northward and eastward transgressive fan-delta system (Virginian Ridge Formation). The sequence grades upward into, and finally is overwhelmed by, locally derived volcanics of the Midnight Peak Formation. Similar, and in part coeval, successor basin sequences throughout the North American Cordillera may have been generated in response to similar tectonic settings.

HURONIAN STRATIGRAPHY OF THE McGREGOR BAY AREA, ONTARIO: RELEVANCE TO THE PALEOGEOGRAPHY OF THE LAKE SUPERIOR REGION

1966 ◽  
Vol 3 (2) ◽  
pp. 203-210 ◽  
Author(s):  
Grant M. Young
Keyword(s):  
United States ◽  
Lake Superior ◽  
Lake Huron ◽  
North Central ◽  
North Shore ◽  
Bay Area ◽  
The North ◽  
Central United States ◽  
Iron Formations

Mapping in the McGregor Bay area of Ontario has shown the presence of a sequence of formations which closely resembles that of the original Huronian of the Bruce Mines–Blind River area. Iron-rich siltstones and argillites above the Lorrain formation are correlated with the lower part of the Animikie iron-formations of the Port Arthur region of Lake Superior and the north central United States. The oldest Proterozoic rocks of the region south of Lake Superior are considered to be correlatives of the Cobalt group of the north shore of Lake Huron.

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