A paleomagnetic study of the layered mafic intrusion at Sept-Îles, Quebec

1987 ◽  
Vol 24 (7) ◽  
pp. 1431-1438 ◽  
Author(s):  
E. I. Tanczyk ◽  
P. Lapointe ◽  
W. A. Morris ◽  
P. W. Schmidt
Keyword(s):  
North America ◽  
Excellent Agreement ◽  
Host Rock ◽  
Remanent Magnetization ◽  
Mafic Intrusion ◽  
Paleomagnetic Study ◽  
Local Host ◽  
Layered Mafic Intrusion ◽  
The One

A paleomagnetic study of gabbroic and anorthositic members of the Sept-Îles layered mafic intrusion has isolated a remanence with direction D = 333°, I = −29 °(remanence A) and a corresponding pole of 141 °E, 20°N. The rocks are cut by numerous diabase dykes of unknown age. The remanence carried by the dykes has direction D = 188°, I = −85 °(remanence B), with a corresponding pole of 116°E, 59°S. Another remanence, statistically identical to B (D = 186°, I = −85°), is found at dyke contacts and in the local host rock; its associated pole, 115°E, 61°S, is identical to the one derived from the dykes. This overprint is significantly different from remanence A, and is obviously related to dyke emplacement. The location of the pole derived from remanence A is in excellent agreement with many other Cambrian poles from a variety of locations throughout cratonic North America. The rocks at Sept-Îles have been previously dated radiometrically at 540 Ma. Thus, all evidence indicates that remanence A is an original thermochemical remanent magnetization, acquired during initial cooling of the intrusion in the Cambrian and prior to the emplacement of the dykes.

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.

Ambulatory Pediatricians of North America, Unite! Run, Do Not Walk to Your Nearest Grammar School

PEDIATRICS ◽  
1969 ◽  
Vol 44 (2) ◽  
pp. 300-301
Author(s):  
Richard B. Goldbloom
Keyword(s):  
North America ◽  
Scientific Information ◽  
Grammar School ◽  
Medical Specialties ◽  
To Come ◽  
The One

The continuing "explosion" of scientific information and the arborization of medical specialties have caused physicians to invent names and catch phrases to define their new activities. Regrettably, much of this latter-day vocabulary is unmusical and clumsy. Some examples represent a downright assault on the English Ianguage. It is alarming that a profession whose members demand such precision in their work would tolerate such slapdash semantic shenanigans. One has winced at such utterances as "examination of the chest showed no pathology;" one has cringed when otherwise esteemed colleagues have indulged in such semantic horrors as "coagulogram" and "febrile agglutinins;" but, in years to come the one atrocity whose promulgation may be remembered with particular mal de mer by the older pediatricians will be the term "ambulatory pediatrics."

Some Economic Aspects of the Brain Drain

1979 ◽  
Vol 9 (4) ◽  
pp. 7-14
Author(s):  
Harry G. Johnson
Keyword(s):  
United States ◽  
North America ◽  
Brain Drain ◽  
The United States ◽  
The Other ◽  
Economic Aspects ◽  
National State ◽  
The One ◽  
Professional People ◽  
The Brain

The concept of “brain drain” is in its origins a nationalistic concept, by which is meant a concept that visualizes economic and cultural welfare in terms of the welfare of the residents of a national state or region, viewed as a totality, and excludes from consideration both the welfare of people born in that region who choose to leave it, and the welfare of the outside world in general. Moreover, though the available statistics are far from adequate on this point, there is generally assumed to be a net flow of trained professional people from the former colonial territories to the ex-imperial European nations, and from Europe and elsewhere to North America and particularly the United States. The concept thus lends itself easily to the expression of anti-colonial sentiments on the one hand, and anti-American sentiments on the other. The expression of such sentiments can be dignified by the presentation of brain drain as a serious economic and cultural problem, by relying on nationalistic sentiments and assumptions and ignoring the principles of economics—especially the principle that in every transaction there is both a demand and a supply—or by elevating certain theoretical economic possibilities into presumed hard facts.

Neogene Faunas of North America

1984 ◽  
Vol 8 ◽  
pp. 128-138
Author(s):  
S. David Webb
Keyword(s):  
North America ◽  
Adaptive Radiation ◽  
Dispersal Patterns ◽  
Faunal Turnover ◽  
The One

The second half of the Age of Mammals yields many stories worth telling. The one that I find grandest and most central, however is the “Savanna Story.” While featuring it as the principle theme, I hope to weave in the following secondary subjects:1) the adaptive radiation of four representative groups, namely hypsodont horses, camels, elephants and cricetid rodents;2) intercontinental dispersal patterns across Beringia and between the American continents;3) and faunal turnover patterns.

Recent development of Arctic air routes

Polar Record ◽  
1962 ◽  
Vol 11 (72) ◽  
pp. 261-264
Author(s):  
John Grierson
Keyword(s):  
North America ◽  
Long Range ◽  
North Pole ◽  
The Real ◽  
The North ◽  
The World ◽  
North Polar ◽  
The One ◽  
Over The Top

Since Andrée's magnificent failure to fly to the North Pole in a balloon in 1897, two great epochs have been marked in polar aviation. The first was the epoch of adventure, lasting nearly 60 years, which attracted to its ranks such men as Roald Amundsen, Lincoln Ellsworth, Umberto Nobile, Richard Byrd, Charles Lindbergh, Gino Watkins and the real father of Arctic aviation, Hubert Wilkins. Many others added their quota of experience until enough was known, and the technique of long-range polar flying had developed sufficiently far, for a regular air line to start operations across the North Polar Basin. That was on 15 November 1954 when Scandinavian Airways System (SAS) opened the first air route over the top of the world, from Europe to North America. This heralded the second epoch—the one of consolidation, and the purpose of this article is to describe very briefly the course of developments during these last seven and a half years.

The Historiographical Legacy of Salo Wittmayer Baron: The Medieval Period

AJS Review ◽  
1993 ◽  
Vol 18 (1) ◽  
pp. 29-37
Author(s):  
Robert Chazan
Keyword(s):  
Twentieth Century ◽  
North America ◽  
Middle Ages ◽  
Jewish History ◽  
Essential Element ◽  
Medieval Period ◽  
History Of ◽  
The One ◽  
Almost All ◽  
The Impact

The impact of Salo Wittmayer Baron on the study of the history of the Jews during the Middle Ages has been enormous. This impact has, in part, been generated by Baron's voluminous writings, in particular his threevolume The Jewish Community and–even more so–his eighteen-volume Social and Religious History of the Jews. Equally decisive has been Baron's influence through his students and his students' students. Almost all researchers here in North America currently engaged in studying aspects of medieval Jewish history can surely trace their intellectual roots back to Salo Wittmayer Baron. In a real sense, many of Baron's views have become widey assumed starting points for the field, ideas which need not be proven or irgued but are simply accepted as givens. Over the next decade or decades, hese views will be carefully identified and reevaluated. At some point, a major study of Baron's legacy, including his influence on the study of medieval Jewish history, will of necessity eventuate. Such a study will have, on the one hand, its inherent intellectual fascination; at the same time, it will constitute an essential element in the next stages of the growth of the field, as it inevitably begins to make its way beyond Baron and his twentieth-century ambience.

Reconciling physical properties with surface seismic data from a layered mafic intrusion

1997 ◽  
Vol 271 (1-2) ◽  
pp. 59-74 ◽  
Author(s):  
D.C. Adams ◽  
K.C. Miller ◽  
H. Kargι
Keyword(s):  
Physical Properties ◽  
Seismic Data ◽  
Mafic Intrusion ◽  
Layered Mafic Intrusion

Extent of Grenvillian remanence components in rocks of the Southern Province

1982 ◽  
Vol 19 (4) ◽  
pp. 698-708 ◽  
Author(s):  
M. Stupavsky ◽  
D. T. A. Symons
Keyword(s):  
Magnetic Field ◽  
North America ◽  
Thin Section ◽  
Sedimentary Rocks ◽  
Pole Position ◽  
River Valley ◽  
Field Reversal ◽  
Paleomagnetic Study ◽  
Northern Portion ◽  
Sediment Matrix

Early Aphebian Gowganda sedimentary rocks and intruding Nipissing diabase sills were sampled for paleomagnetic study at 88 sites (~500 cores, ~1000 specimens) along two ~42 km long profiles extending north from the Grenville Front into the Cobalt Plate of the Southern Structural Province in the River Valley – Lake Temagami area of Ontario. After AF demagnetization a postfolding pre-Nipissing ~2200 Ma remanence was found in eight of the 37 Gowganda sediment sites that were > 2 km north of the front, giving a pole at 109°W, 63°N (dp = 10°, dm = 19°). The Nippissing diabase from > 2 km north of the front retains a stable antiparallel prefolding N1 remanence direction in 22 of 40 sites, giving a pole position of 85°W, 17°S (dp = 6°, dm = 10°). These "south and down" remanence directions found in the southern portion of the plate contrast with the antiparallel "north and up" directions found in the northern portion, thereby indicating the occurrence of either two nearly cogenetic Nipissing intrusive events or the sequential emplacement of the Nipissing during an Earth's magnetic field reversal across the plate. At two sites a Nipissing remagnetized remanence was found in Gowganda sediments with a pole of 115°W, 18°S. Also three "Nipissing" sites give a pole at 164°W, 3°N, which is close to the known pole for the later ~1.25 Ga Sudbury olivine diabase dikes. One site is adjacent to a large dike and two were found on thin-section examination to be olivine diabase. The eight sites in Gowganda sediment matrix and conglomerate clasts and in Nipissing diabase from within < 2 km from the front were found to have a postfolding metamorphic remanence with a Grenville orogenic pole at 45°W, 51°N (dp = 19°, dm = 21°). Finally, the results lead to a suggested revision in the APW path for the ~2300–~1650 Ma interval for North America.

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