Paleomagnetism of the Precambrian Martin Formation, Saskatchewan

1973 ◽  
Vol 10 (10) ◽  
pp. 1485-1493 ◽  
Author(s):  
M. E. Evans ◽  
D. K. Bingham
Keyword(s):  
North America ◽  
Strong Evidence ◽  
Sedimentary Basins ◽  
Canadian Shield ◽  
Igneous Rocks ◽  
Paleomagnetic Pole ◽  
Oriented Samples ◽  
The Subject

Oriented samples of the Martin Formation were collected from 23 sites, both sediments and igneous rocks being represented. Detailed laboratory treatment yields an overall mean direction corresponding to a paleomagnetic pole at 9 °S, 72 °W (dp = 6.3°, dm = 11.5°). Strong evidence for the primary nature of the magnetization involved is provided by a positive fold test. The paleomagnetic pole obtained provides further evidence for a major eastward loop in the polar wandering path for North America during late Aphebian – early Helikian times. The exact age of Martin Formation deposition is the subject of debate, but extreme limits given by various authors are 1930 to 1490 m.y. However, the paleomagnetic results themselves somewhat restrict this range, and are of use in setting up a regional chronology, since they enable stratigraphic correlations between isolated sedimentary basins of the Canadian Shield to be made.

Paleomagnetism of igneous rocks from the Belcher Islands, Northwest Territories, Canada

1980 ◽  
Vol 17 (7) ◽  
pp. 807-822 ◽  
Author(s):  
P. W. Schmidt
Keyword(s):  
North America ◽  
Northwest Territories ◽  
Igneous Rock ◽  
Pole Position ◽  
Igneous Rocks ◽  
Hudson Bay ◽  
Plate Model ◽  
Polar Wander ◽  
Apparent Polar Wander Path ◽  
Paleomagnetic Pole

Paleomagnetic results from igneous rock units on the Belcher Islands, Hudson Bay, are described. Fold tests for all units studied, as well as a contact test for the intrusive bodies, indicate that both primary (initial), and secondary (post-folding) magnetizations are present.The paleomagnetic pole position from primary directions of the oldest unit studied, the Eskimo volcanics, is situated at 40°S, 002°E (A95 = 12°) and is similar to that derived from equivalent volcanics on the mainland. The younger volcanic unit studied, the Flaherty volcanics, yielded a pole position from primary directions at 0°, 244°E (A95 = 7°). The Haig intrusions, associated with these younger volcanics, yields an almost identical pole position at 1°N, 247°E (A95 = 6°), being derived from directions which are shown to be not only pre–folding but also date from initial cooling. The Eskimo volcanics, which have been more deeply buried than the Flaherty (upper) volcanics, carry substantial components of secondary (post-folding) magnetization which yield a pole position at 19°N, 243°E (A95 = 15°), about 20° north of the pole positions derived from the youngest units.It is argued that the apparent polar wander path (APWP) constructed for the Belcher Islands is representative of the mainland Ungava Craton. Comparison with the equivalent APWP from elsewhere in North America shows that the two APWP's are at variance. Although a two-plate model could be advanced, perhaps a more conservative interpretation is to extend the existing North American APWP eastward to include the Belcher–Ungava APWP, that is, to favour a one-plate model.

PALAEOMAGNETISM OF DIABASE DYKES OF THE CANADIAN SHIELD

1965 ◽  
Vol 2 (4) ◽  
pp. 278-298 ◽  
Author(s):  
W. F. Fahrig ◽  
E. H. Gaucher ◽  
A. Larochelle
Keyword(s):  
Remanent Magnetization ◽  
Lake Superior ◽  
Canadian Shield ◽  
Igneous Rocks ◽  
Palaeomagnetic Data ◽  
The World ◽  
Oriented Samples ◽  
The Mean ◽  
The Individual ◽  
Dyke Swarms

Some areas of the Canadian Shield are profusely intruded by swarms of subparallel basaltic dykes. These typically have a diabasic texture and formerly were considered to be strictly the intrusive equivalents of tholeiitic flood basalt.About 650 oriented samples were collected from about 25 dyke swarms and preliminary palaeomagnetic data from six of them are presented here. The Mackenzie swarm has a K–Ar age of 1 295 million years, occurs throughout the western Canadian Shield, and is the most extensive swarm of basic dykes known anywhere in the world. The other swarms are the Molson dykes (1 445 m.y.) in northeastern Manitoba, the Marathon dykes (1 810 m.y.) just north of Lake Superior, the Sudbury dykes (1 285 m.y.) of southeastern Ontario, the Matachewan dykes (2 485 m.y.) of western Quebec and northeastern Ontario, and the Abitibi dykes (1 230 m.y.), which occur from Sault Ste. Marie, Ontario, to Lake Mistassini, Quebec.The palaeomagnetic virtual pole positions of six swarms were derived from the mean of their measured remanent magnetization directions. These directions of magnetization were determined from the samples after they were magnetically washed in an a-c. field of 80 or 130 oersteds. The reasons for the dispersion within the individual swarms are discussed. The pole positions of the Sudbury and Mackenzie dykes are almost identical and the two swarms are the same age within the limits of analytical uncertainty. However, basalt of the Sudbury swarm is alkalic and more undersaturated than basalt of the Mackenzie dykes.No evidence was found to contradict the usual assumption that unaltered basic igneous rocks of this type acquire and generally retain a stable magnetization which was parallel with the earth's magnetic field at the time of the dyke intrusion.

Paleomagnetism of the Michael Gabbro and Possible Evidence of the Rotation of Makkovik Subprovince

1972 ◽  
Vol 9 (10) ◽  
pp. 1287-1296 ◽  
Author(s):  
W. F. Fahrig ◽  
A. Larochelle
Keyword(s):  
North America ◽  
Remanent Magnetization ◽  
Pole Position ◽  
Canadian Shield ◽  
Main Body ◽  
Central Coast ◽  
Tectonic Event ◽  
South Central ◽  
Paleomagnetic Pole ◽  
Paleomagnetic Study

The Michael gabbro forms a belt of thick, predominantly southerly-dipping sheets which extends 200 km inland from the south-central coast of Labrador. The intrusions lie largely within the Makkovik subprovince, have a radioisotopic age of 1500 m.y., and are reversely magnetized with a paleomagnetic pole position of 163 °E, 10 °N. The paleomagnetic results indicate that most of the rocks internal to this belt have not been deformed since the intrusions acquired a stable remanent magnetization, presumably at the time of cooling 1500 m.y. ago. However, the Michael pole position differs significantly from those of rocks of similar age elsewhere in North America. This suggests rotation of the block containing the Michael intrusions relative to these other rocks. The Aillik dikes which also lie within the Makkovik sub-province have a radioisotopic age of about 1100 m.y. and a pole position consistent with that of rocks of similar age elsewhere in the Canadian Shield. The postulated Michael rotation must then have taken place between 1500 and 1100 m.y. ago.The rock at two of the most southerly sites sampled for paleomagnetic study proved to be magnetically unstable and the rock at a third such site, though stably magnetized has a magnetization significantly different from the main body of Michael gabbro intrusions. These three sites may indicate a post-consolidation thermal and tectonic event and their position may help define the Grenville Front in this region.

The paleomagnetism of the Croker Island Complex, Ontario, Canada

1969 ◽  
Vol 6 (2) ◽  
pp. 213-218 ◽  
Author(s):  
H. C. Palmer
Keyword(s):  
North America ◽  
Remanent Magnetization ◽  
Pole Position ◽  
Lake Huron ◽  
Time Interval ◽  
Significant Shift ◽  
Paleomagnetic Pole ◽  
Oriented Samples

Meaningful paleomagnetic results were obtained from 23 of 30 oriented samples from the Croker Island Complex, North Channel of Lake Huron, Canada. The age of the complex is estimated to be 1475 ± 50 m.y. from a Rb–Sr isochron. The paleomagnetic pole calculated from the directions of remanent magnetization after partial ac demagnetization is 143 °West, [Formula: see text] North. This result, when compared with other paleomagnetic results from North America, indicates little or no polar wandering in the time interval 1.48 b.y. to 1.1 b.y. However, a significant shift in the pole position is indicated during the time interval 1.7 to 1.48 b.y.

scholarly journals I.—History of the Names Cambrian and Silurian in Geology

1873 ◽  
Vol 10 (111) ◽  
pp. 385-395 ◽  
Author(s):  
T. Sterry Hunt
Keyword(s):  
Great Britain ◽  
North America ◽  
Upper Cambrian ◽  
History Of ◽  
Lower Palaeozoic ◽  
The Subject

It is proposed in the following pages to give a concise account of the progress of investigation of the lower Palæozoic rocks during the last forty years. The subject may naturally be divided into three parts: 1. The history of Silurian and Upper Cambrian in Great Britain from 1831 to 1854; 2. That of the still more ancient Palæozoic rocks in Scandinavia, Bohemia, and Great Britain up to the present time, including the recognition by Barrande of the so-called primordial Palæozoic; fauna; 3. The history of the lower Palæozoic rocks of North America.

scholarly journals Argument ellipsis in Colloquial Singapore English and the Anti-Agreement Hypothesis

2013 ◽  
Vol 50 (2) ◽  
pp. 365-401 ◽  
Author(s):  
YOSUKE SATO
Keyword(s):  
Strong Evidence ◽  
Recent Theory ◽  
Argument Position ◽  
Comparative Syntax ◽  
Argument Ellipsis ◽  
Principled Explanation ◽  
The Subject

This paper provides new data from Colloquial Singapore English (CSE) showing a hitherto unnoticed subject–object asymmetry: empty objects, but not empty subjects, exhibit sloppy/quantificational readings. According to a recent theory of argument ellipsis in Japanese/Korean (Oku 1998; S. Kim 1999; Takahashi 2007, 2008a, b, 2010), these readings obtain as a result of the LF-Copy of an overt argument from a full-fledged clause onto the corresponding empty argument position in an elliptical clause. Şener & Takahashi (2010) and Takahashi (2010) hypothesize that this operation is blocked by ϕ-agreement. This hypothesis provides a principled explanation for the subject–object asymmetry in CSE, coupled with the new observation that primary substrates of CSE – Mandarin, Cantonese, Hokkien and Malay – exhibit the same asymmetry as CSE. My analysis has significant implications for the comparative syntax of argument ellipsis and for theories of contact genesis. Among others, the analysis supports the claim (Miyagawa 2010) that Chinese possesses ϕ-agreement despite the lack of morphological manifestations. The results in this paper also provide strong evidence for the general substratist explanation on the emerging grammar of CSE (Bao 2005).

scholarly journals I.—The Metamorphosis of the Lizard Gabbros

1886 ◽  
Vol 3 (11) ◽  
pp. 481-489 ◽  
Author(s):  
J. J. H. Teall
Keyword(s):  
Mechanical Energy ◽  
Earth Pressure ◽  
Careful Consideration ◽  
Point Of View ◽  
Igneous Rocks ◽  
General Point ◽  
Present Moment ◽  
General View ◽  
Original Rock ◽  
The Subject

If we take a general view of the present position of geological science, we are struck by the fact that, although there is substantial agreement amongst geologists on matters relating to the origin of the rocks usually designated as aqueous and igneous, the greatest diversity of opinion prevails with regard to the circumstances under which the so-called metamorphic rocks have been produced. Every fragment of evidence calculated to throw light on the origin of these rocks, therefore, deserves the most careful consideration. Of recent years special attention has been directed to the effects of mechanical energy in modifying the mineralogical and structural characters of rocks originally formed by aqueous and igneous agencies; and a suspicion has been aroused that it is in this direction that we must look for a solution of many of the problems connected with the origin of the crystalline schists. A visit to the Lizard Peninsula of Cornwall during the present summer has convinced me of the immense importance of this view so far as that district is concerned. That portion of the peninsula which lies south of a line drawn from Porthalla on the east to Polurrian Cove on the west is formed.partly of igneous rocks—such as gabbro, greenstone, serpentine, and granite—and partly of crystalline schists. The igneous rocks, in certain places, become foliated and sohistose and sometimes show a definite banding due to a variation in the relative proportions of the different constituents. In other words they present characters which are usually regarded as distinctive of the crystalline schists. There is, moreover, evidence to show that these characters are mainly the result of a yielding to earth-pressure subsequent to the consolidation of the original rock. At the present moment, having just returned from the district, I am unable to treat the subject from a general point of view with any prospect of success; but it has occurred to me that some details with regard to one of the rocks may not be without interest to members of the Association.

scholarly journals ICD, Mental Disorder and British Nosologists: An assessment of the uniquely British contribution to psychiatric classification

1994 ◽  
Vol 165 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Michael Shepherd
Keyword(s):  
North America ◽  
Mental Disorder ◽  
Historical Survey ◽  
Psychiatric Classification ◽  
The Subject ◽  
The Uk ◽  
National Systems ◽  
The Way

During several recent international meetings on classification, there have been frequent references to national systems of classification developed and used in Europe, North America and many other countries. The UK has been notably absent from this list. As Professor Kendell, in his brief historical survey of the subject, points out: “British psychiatry does not have, and indeed never has had, any important diagnostic concepts of its own in the way that French, American, and Scandinavian psychiatry still do” (Kendell, 1985).

Luhmann’s ›Other‹ Book on Law: Observations on the Reception of Niklas Luhmann’s A Sociological Theory of Law

2014 ◽  
Vol 19 (1) ◽  
Author(s):  
Marc Hanna
Keyword(s):  
North America ◽  
Sociological Theory ◽  
Sociology Of Law ◽  
Substantial Impact ◽  
Legal Scholarship ◽  
The Subject ◽  
Nuanced Understanding ◽  
Theory Of Law ◽  
Anglophone World ◽  
Relative Accessibility

AbstractEven though Niklas Luhmann’s general sociology of law has made a substantial impact upon socio-legal scholarship in the Anglophone world in recent years, his first book on the subject to be translated into English has received relatively little attention. The paper presents this as something of an anomaly by highlighting both the relative accessibility of the book and the way in which it has proved foundational for systems theoretical accounts of law in world society. In tracing the book's reception in both Britain and North America, the paper identifies the general problems of timing and communication the book faced. But it also considers whether the relatively humanist undertones of the book's focus on the development of law from the interaction of individuals proves unsettling to the now relatively more accepted concept of law as autopoiesis. The paper concludes, however, that it is this which should recommend the book to a contemporary audience, as offering a more nuanced understanding of Luhmann’s sociology of law and the potential contained therein.

Does Civil Society Matter? Governance in Contemporary India

2006 ◽  
Vol 39 (2) ◽  
pp. 456-457
Author(s):  
Reeta Chowdhari Tremblay
Keyword(s):  
Civil Society ◽  
North America ◽  
Case Studies ◽  
New Delhi ◽  
Actual Case ◽  
The North ◽  
Fresh Perspective ◽  
The Subject ◽  
The Relationship ◽  
Theoretical Conceptualization

Does Civil Society Matter? Governance in Contemporary India, Rajesh Tandon and Ranjita Mohanty, eds., New Delhi: Thousand Oaks, London: Sage Publications, 2003, pp. 363.In the last decade in North America, there has been an explosion of books on the subject of civil society. Like so many other concepts in contemporary political science, the notion of civil society has been imported to analyze other polities outside the North American hemisphere, and India is no exception. However, Tandon and Mohanty's edited book presents a fresh perspective by combining academic analysis with that of on-the-ground practitioners to examine the relationship between civil society and governance. The book is divided into two parts: the first deals with the theoretical conceptualization of civil society and the second with actual case studies.

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