Electrical Conductivity Structure in Western Canada and Petrological Interpretation

Caner, B.

doi:10.5636/jgg.22.113

Cited by 47 publications

(24 citation statements)

References 50 publications

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“…An example of one extreme is the mobile belt of western Canada, where the GCE persists for only a short distance inland. The lower crust there is thought to be hydrated [Caner, 1970]. The other extreme is the shield of western Australia, where the GCE persists far inland and magnetotelluric results indicate low conductivity throughout the crust and upper mantle [Everett and Hyndman, 1967b].…”

Section: Tectonic Implicationsmentioning

confidence: 99%

The geomagnetic coast effect

Parkinson¹,

Jones²

1979

Reviews of Geophysics

120

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Section: Tectonic Implicationsmentioning

confidence: 99%

The geomagnetic coast effect

Parkinson¹,

Jones²

1979

Reviews of Geophysics

120

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“…In western Canada, two geomagnetic regions separated by a well-defined boundary have been distinguished, a western one characterized by low I values and an eastern one characterized by high I values (Caner and Cannon 1965, Caner 1970, Camfield et al 1971. Although the boundary lies to the west rather than the east of the Rocky Mountains, it runs parallel to the stable craton edge.…”

Section: Data Presentationmentioning

confidence: 98%

“…The remaining, largely inland, anomalies have been attributed to electrical conductivity contrasts produced by a variety of geological conditions. These have included lateral variations in the conductivity and thickness of sediments (Untiedt 1970), the presence of highly conductive layers in the deeper crust (Niblett and Whitham 1970), possibly as a result of hydration (Caner 1970), and a rise in the isotherms in the upper mantle (Reitzel et al 1970). The association of g.v.a.…”

Section: Introductionmentioning

confidence: 98%

A Geographical Relation Between Geomagnetic Variation Anomalies and Tectonics

Law¹,

Riddihough²

1971

Can. J. Earth Sci.

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A world review of the available geomagnetic variation data, with a standardized presentation of results from North America and Europe, shows that there is a geographical relation between inland geomagnetic variation anomalies and tectonic features. Particularly evident in North America is a correlation between anomalies and the edge of the stable craton. Other anomalies are situated along fold belts (eastern Canadian Arctic) and rift-fault zones (Rhine Graben, Iceland). With the exception of that in Japan, all reported anomalies are shown to occur within these three tectonic categories. In terms of plate theory, these categories and the island arc system related to Japan are characteristic of past or present plate boundary zones. A close association between plate margins and geomagnetic variation anomalies is thus implied.Une revue B I'echelle du globe des donnees geomagnetiques, presentees de facon standard en ce qui concerne 1'AmCrique du Nord et I'Europe, montre qu'il existe une relation geographique entre les variations des anomalies gComagnCtiques et la tectonique. En Amerique du Nord, en particulier, il y a une correlation Cvidente entre les anomalies et la bordure du craton. Les autres anomalies suivent les chaines plissees (Arctique canadien oriental) et les fosses tectoniques (Fosse Rhenan, Islande). A part le Japon, toutes les anomalies connues coincident avec I'une des trois zones tectoniques ci-dessus. Si on se refkre B la theorie des plaques orogeniques, ces zones tectoniques et les gi~irlandes insulaires, type Japon, correspondent A des zones de suture anciennes ou actuelles. I1 y aurait donc une liaison ktroite entre les zones de suture des plaques tectoniques et les variations des anomalies magnetiques.

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“…The 1969 array extended the investigation of western North America north of the Basin and Range Province and into the Canadian Cordillera. Here HYNDMAN (1963), CANER (1970), andCOCHRANE andHYNDMAN (1970) had shown that vertical component fields of periods less than 2 hr were attenuated in the Cordillera. This was confirmed by the array .…”

Section: Electrical Conductivity Structurementioning

confidence: 99%

“…Two-dimensional modelling was used to fit a steps-plus-ridges type of conductive model to these anomalies and to the normal fields on each side . CANER (1970) andCOCHRANE andHYNDMAN (1970) had fitted the normal fields with a model having a conductive layer in the lower crust of the western region. Camfield and Gough have added daily-variation long-period data to the substorm data, and find the mantle step-and-ridge model of to be in conflict with the daily variation data.…”

Section: Electrical Conductivity Structurementioning

confidence: 99%

Electrical conductivity under Western North America in relation to heat flow, seismology, and structure.

Gough

1974

J. geomagn. geoelec

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Western North America between the coastal ranges and the Great Plains, and from the Mexican-United States border to the Trans-Canada Highway has been studied by means of three large two-dimensional arrays of recording magnetometers. The paper discusses the conductive structures found by these arrays in the upper mantle of the region. Highly conductive mantle material at least 100 km thick for conductivity 0.2 S/m underlies the Basin and Range Province and ridges of still higher conductivity (or greater thickness for a given conductivity) underlie the Wasatch Fault Belt and Southern Rockies. Under the Great Plains the upper mantle is more resistive and is of sub-shield type. North of the Basin and Range the Cordillera have a thin layer (10-20 km at 0.2 S/m) of conductive material in the upper mantle and the conductivity indicates a lower level of tectonic activity than in the midlatitudes of the U.S.A. Under the Colorado Plateau the conductivity is of Great Plains type or intermediate between this and that beneath the Basin and Range. Alternative conductive models satisfying variation-field anomalies are discussed with special reference to the poor depth and excellent lateral resolution of magnetometer arrays. The distribution of heat-flow is compared with that of electrical conductivity and it is shown that there is generally close correspondence and full support for association of high conductivity with high temperature. Seismological velocity-depth profiles, station terms in P and S teleseismic times and other parameters are considered and are again consistent with the conductivity and geothermal information.The case for partial melting is considered. It is strongly supported by seismological parameters in the lowvelocity layer and gives the most plausible hypothesis for the contrasts of order 100 in conductivity required by the magnetometer array results. Three tentative suggestions are made concerning tectonics of the region.

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Electrical Conductivity Structure in Western Canada and Petrological Interpretation

Cited by 47 publications

References 50 publications

The geomagnetic coast effect

The geomagnetic coast effect

A Geographical Relation Between Geomagnetic Variation Anomalies and Tectonics

Electrical conductivity under Western North America in relation to heat flow, seismology, and structure.

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