Paleomagnetism of the Caldwell lavas, Eastern Townships, Québec.



Forty two oriented samples (97 specimens) were obtained from 17
sites in metavolcanic rocks from the Caldwell Group of the Appalachians
of Southern Québec (longitude: 71u00'-71"30' W, latitude: 46°00'-46"10'N).
These metavolcanics of Lower Cambrian age are massive or pillowed lavas
of andesitic and mainly basaltic composition metamorphosed to the
sub-greenschist facies. Magnetite and occasionally hematite are the frequent
magnetic memory carrier.
In order to obtain some pertinent information relative to the stability
of the remanent magnetization component, stepwise alternating field
demagnetization was conducted on 35% of the specimens and the others
were demagnetized at an optimum alternating field. After AF treatment,
the paleopole position of the tilted formation from 16 localities is 148°E,
43°N (dp=11.3°, dm = 22.4°). After omission of 3 localities for which
a95>30°, the new paleopole position obtained is 173°E, 26°N. This formation
of Early Cambrian age is characterized by a reversed polarity.

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Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X