| Summary: | As part of a major study of the Avalon zone in eastern Newfoundland, the paleomagnetism of the Finn Hill ignimbrite sequence located in the Colliers-Harbour Main area is described. Detailed alternating field and thermal experiments performed on this Hadrynian ash-flow tuff sequence indicate that it is characterized by two significantly different mean directions of magnetization; I) A(S-l28, I=+25, α95 =7.1°, K-171, N=4 sites) in-situ and (D=225, D + 59, α95=13°, K=48) after tilt correction, 2) B (D=69, I=+52, N= 2 sites) in-sltu and (D=303, I=+40) after tilt correction. The A component is believed to be secondary and the paleopole corresponding to the in-situ direction of magnetization is I4°S, l°W. The B tilt corrected component (D=303, I=+40) is interpreted as a pre- or syn-folding direction of magnetization corresponding with the time of formation of the ignimbrite sequence or slightly later; its corresponding paleopole position Is 39°S, 29°E. It is worth noting that the paleopole (14°S, 1°W) of the secondary component found in the present study is not significantly different from the paleopole (5°S, 8°W) obtained in the Cloud Mountain basalt overlying Grenville basement of northwestern Newfoundland, the age of which is close to latest Precambrian (≈620 Ma), this suggests that in tate Precambrian time, the eastern and western Newfoundland blocks were not very distant from each other or else they were far apart but at the same paleolatitude. The secondary component is Interpreted as representing the magnetic imprint of the Avalonian (Cadomlan) orogenic event. This last interpretation is reasonable since nearby Cambrian units (to the west) are located unconformably above the Precambrian units and are almost flat lying. Consequently, the chances of this secondary component being of Acadian age are relatively small. The new data set of this research fills a definite gap in the paleomagnetic record of the Avalon zone. RÉSUMÉ La description du paléomagnetlsme de la séquence ...
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