A possible Proterozoic plate boundary in North America

A long, narrow belt of rocks of very high electrical conductivity has been discovered and mapped by means of large arrays of recording magnetometers, over a distance of 1400 km from southeastern Wyoming to the edge of the Canadian Shield in Saskatchewan. Evidence that the conductive belt might be associated with conductive minerals in metamorphosed and fractured rocks in the basement has been discussed in earlier papers. Recent results on the Precambrian geology at both ends of the conductor, in the Churchill Province of the Shield and in southeastern Wyoming, support the hypothesis that the anomaly in electrical conductivity traces a major fracture zone in the lithosphere of Precambrian North America. This paper presents and relates various lines of evidence which together tend to substantiate such a fracture zone or mobile belt. From the age and composition of rocks near the southern end of the structure, Hills and others suggest that a Proterozoic subduction zone is located there. It is possible that the entire fracture zone from the Southern Rockies to the vicinity of Hudson Bay is a Proterozoic continental collision zone or geosuture.

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A geomagnetic induction anomaly from IMS data near Hudson Bay, and its relation to crustal electrical conductivity in central North America

Geophysical Journal International ◽

10.1111/j.1365-246x.1985.tb01349.x ◽

1985 ◽

Vol 81 (1) ◽

pp. 33-46 ◽

Cited By ~ 20

Author(s):

J. C. Gupta ◽

R. D. Kurtz ◽

P. A. Camfield ◽

E. R. Niblett

Keyword(s):

Electrical Conductivity ◽

North America ◽

Hudson Bay ◽

Geomagnetic Induction

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THE EVOLUTION OF THE COASTAL ZONE OF THE PACIFIC - NORTH AMERICA PLATE BOUNDARY IN CENTRAL AND NORTHERN CALIFORNIA: INSIGHTS FROM GEOMORPHIC, GEOLOGIC AND THERMOCHRONOLOGIC RECORDS

10.1130/abs/2017am-306354 ◽

2017 ◽

Author(s):

Jeremy Hourigan ◽

◽

Alexander N. Steely ◽

Jeffrey W. Beeson ◽

Samuel Y. Johnson ◽

...

Keyword(s):

North America ◽

Coastal Zone ◽

Plate Boundary ◽

Northern California ◽

The Pacific

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MODELING THE DEFORMATION EVOLUTION OF THE WESTERN U.S. BASIN AND RANGE PROVINCE WITHIN THE PACIFIC-NORTH AMERICA PLATE BOUNDARY ZONE SINCE 36 MILLION YEARS AGO

10.1130/abs/2017am-307960 ◽

2017 ◽

Author(s):

Alireza Bahadori ◽

◽

William E. Holt ◽

Troy Rasbury

Keyword(s):

North America ◽

Plate Boundary ◽

Basin And Range ◽

Boundary Zone ◽

Basin And Range Province ◽

The Pacific ◽

Plate Boundary Zone

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Late Quaternary uplift along the North America-Caribbean plate boundary: Evidence from the sea level record of Guantanamo Bay, Cuba

Quaternary Science Reviews ◽

10.1016/j.quascirev.2017.10.024 ◽

2017 ◽

Vol 178 ◽

pp. 54-76 ◽

Cited By ~ 3

Author(s):

Daniel R. Muhs ◽

Eugene S. Schweig ◽

Kathleen R. Simmons ◽

Robert B. Halley

Keyword(s):

North America ◽

Sea Level ◽

Late Quaternary ◽

Plate Boundary ◽

Caribbean Plate ◽

The North ◽

Guantanamo Bay

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Morphological and isozyme variation in Salicornia europaea (s.l.) (Chenopodiaceae) in northeastern North America

Canadian Journal of Botany ◽

10.1139/b87-195 ◽

1987 ◽

Vol 65 (7) ◽

pp. 1410-1419 ◽

Cited By ~ 27

Author(s):

S. L. Wolff ◽

R. L. Jefferies

Keyword(s):

North America ◽

Atlantic Coast ◽

Hudson Bay ◽

Salicornia Europaea ◽

Electrophoretic Variation ◽

James Bay ◽

Northeastern North America ◽

Electrophoretic Patterns ◽

Anther Length ◽

Vegetative Characters

Morphological and electrophoretic variation has been documented within and among populations of Salicornia europaea L. (s.l.) in northeastern North America. Univariate and multivariate analyses (discriminant analyses) of measurements of floral and vegetative characters delimited three morphologically distinct groups of populations: Atlantic coast tetraploids (2n = 36), Hudson Bay diploids, and Atlantic coast and James Bay diploids (2n = 18). The two diploid groups were morphologically distinct from the midwestern diploid, S. rubra Nels., based on anther length, width of the scarious border of the fertile segment, and the overall width of the fertile segment. Electrophoretic evidence supported the delimitation of the three distinct morphological groups of populations of S. europaea with the exception of the population from James Bay, which had electrophoretic patterns identical with those of plants from Hudson Bay but resembled the Atlantic coast diploids morphologically. Most enzyme systems assayed were monomorphic. Only homozygous banding patterns were detected in diploid plants and electrophoretic variation was not observed within populations of S. europaea or S. rubra but was detected between groups of populations. Four multilocus phenotypes were evident; these corresponded to the major groups recognized on the basis of ploidy level and morphology. Reasons that may account for the paucity of isozymic variation are discussed.

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Distribution of the middorsal stripe dimorphism in the wood frog, Rana sylvatica, in eastern North America

Canadian Journal of Zoology ◽

10.1139/z80-226 ◽

1980 ◽

Vol 58 (9) ◽

pp. 1643-1651 ◽

Cited By ~ 2

Author(s):

Frederick W. Schueler ◽

Francis R. Cook

Keyword(s):

United States ◽

North America ◽

Rana Sylvatica ◽

Wood Frog ◽

Eastern North America ◽

Hudson Bay ◽

Northeastern United States ◽

Southern Ontario ◽

Maritime Canada ◽

Eurasian Species

The frequency of the middorsally striped morph of Rana sylvatica in Ontario and Manitoba varies from absence in southern Ontario to 80% on the coast of Hudson Bay, with a general value of 20–30% in the boreal forest, a rise to 50% on the forest–grassland ecotone in southern Manitoba, and a decline westward to 20% on the edge of the prairies. This morph is rare in the northeastern United States and Maritime Canada. The suggested relationship between its frequency and the "grassiness" of the background on which predators view it is reexamined, and it is suggested that a linkage with earlier transformation as demonstrated in Eurasian species may explain certain anomalies.

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Investigation of the relationship between landform classes and electrical conductivity (EC) of water and soil using a fuzzy model in a GIS environment

Solid Earth ◽

10.5194/se-7-873-2016 ◽

2016 ◽

Vol 7 (3) ◽

pp. 873-880

Author(s):

Marzieh Mokarram ◽

Dinesh Sathyamoorthy

Keyword(s):

Electrical Conductivity ◽

Fuzzy Model ◽

Chemical Properties ◽

Geographical Information ◽

Fars Province ◽

Fuzzy Method ◽

The North ◽

The Relationship ◽

Very High ◽

Soil And Water

Abstract. Soil genesis is highly dependent on landforms as they control the erosional processes and the soil physical and chemical properties. The relationship between landform classification and electrical conductivity (EC) of soil and water in the northern part of Meharloo watershed, Fars province, Iran, was investigated using a combination of a geographical information system (GIS) and a fuzzy model. The results of the fuzzy method for water EC showed 36.6 % of the land to be moderately land suitable for agriculture; high, 31.69 %; and very high, 31.65 %. In comparison, the results of the fuzzy method for soil EC showed 24.31 % of the land to be as not suitable for agriculture (low class); moderate, 11.78 %; high, 25.74 %; and very high, 38.16 %. In total, the land suitable for agriculture with low EC is located in the north and northeast of the study area. The relationship between landform and EC shows that EC of water is high for the valley classes, while the EC of soil is high in the upland drainage class. In addition, the lowest EC levels for soil and water are in the plains class.

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Present and postglacial rates of uplift for glaciated northern and eastern North America derived from postglacial uplift curves

Canadian Journal of Earth Sciences ◽

10.1139/e70-069 ◽

1970 ◽

Vol 7 (2) ◽

pp. 703-715 ◽

Cited By ~ 43

Author(s):

J. T. Andrews

Keyword(s):

North America ◽

Eastern North America ◽

Hudson Bay ◽

High Cell ◽

Uplift Rate ◽

Radiocarbon Dates ◽

Marine Deposits ◽

Maximum Value ◽

Current Maximum ◽

A Current

Average rates of postglacial uplift reach a maximum value of nearly 4 m 100 y−1 over southeastern Hudson Bay, and another high cell, with rates of about 2.5 m 100 y−1, lies between Bathurst Inlet and Southampton Island. Current rates of uplift are underestimated if exponential curves are fitted solely to dated raised marine deposits without considering the amount of future recovery. Rates of rebound are, instead, derived from A/t where A is uplift in the first 1000 y since deglaciation, and t is time since deglaciation. For the northwest margin of the former ice sheet coefficients of determination for rate of uplift, at specific times, as a function of distance are [Formula: see text]. Maps of rates of uplift for northern and eastern North America are presented for 8000 y B.P., 6000 y B.P. and the present day. They reveal the existence of three uplift centers and show that rates of uplift declined from a maximum of 10 to 12 m 100 y−1, immediately following deglaciation, to a current maximum of about 1.3 m 100 y−1. Agreement is satisfactory when calculated rates of uplift are compared with those derived from geological observations, radiocarbon dates, and from water-level records. A final map shows isochrones on the uplift rate of ~1 m 100 y−1. The rate dropped to this value about 10 000 y ago on the outer northwest and southeast coasts, whereas the value might not be reached for another 2000 y in southeastern Hudson Bay.

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