PALAEOMAGNETISM AND TECTONICS, A REVIEW

A critical review is given of applications of palaeomagnetism to tectonics in its broadest sense. Only the most general geotectonic problems, such as the hypotheses of continental drift and/or seafloor spreading have been excluded. Palaeomagnetic studies of the following areas and tectonic structures have been reviewed (they are numbered for the sake of easy reference): (1) Newfoundland; (2) the Lewis thrust plate; (3) the Appalachian Mountains; (4) the Columbia arc (northwestern U.S.A.); (5) Japan; (6) the Arabian Peninsula; (7) the Inner Sudetic Basin and the Bohemian Massif; (8) the Choč nappe (Carpathian Mountains); (9) the Iberian Peninsula; (10) Corsica; (11) Sardinia; (12) the Southern Alps (northern Italy) and their bearing on major shear movements in the Tethys mobile belt; (13) anticlines of the Tadzhik Depression (Uzbek and Tadzhik S.S.R.); (14) the younger gabbros of Aberdeenshire, Scotland. A limited number of related problems are touched upon. The present reviewers conclude that the following ideas must be accepted on the basis of the available palaeomagnetic evidence: the absence of differential rotations within the Lewis thrust plate (2), the bending of Japan (5), the relative rotation of the Inner Sudetic Basin and the Bohemian Massif (7), the rotation of the Choč nappe (8), the anti-clockwise rotation of the Iberian Peninsula (9), the secondary distortion of the anticlines of the Tadzhik Depression (13) and the absence of differential post-consolidation movements in the younger gabbros of Aberdeenshire (14), the non-oroclinal nature of the Appalachians in Pennsylvania (3). There is strong palaeomagnetic evidence for the oroclinal nature of the Columbia arc (Mendocino and Idaho coupled oroclines, 4) and the rotation of Corsica (10) and Sardinia (11). Still essentially undecided are the rotation of Newfoundland (1), and the rotation of Arabia (6). The claim for major dextral shear movements in the Mediterranean area, based on palaeomagnetic studies in northern Italy (12) is considered as not having been established. © 1969.