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Detailed Reference Information |
Meert, J.G., Van der Voo, R. and Payne, T.W. (1994). Paleomagnetism of the Catoctin volcanic province: A new Vendian-Cambrian apparent polar wander path for North America. Journal of Geophysical Research 99: doi: 10.1029/93JB01723. issn: 0148-0227. |
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The Vendian/Cambrian segment of the Laurentian apparent polar wander path (APWP) has been poorly constrained and the subject of some controversy. The Catoctin volcanic province in central Virginia is well-dated at 570¿35 Ma (Rb-Sr) and 597¿18 Ma (U-Pb) and therefore presented an excellent paleomagnetic target for resolving the Laurentian Vendian-Cambrian APWP. A total of 206 samples from 32 sites were collected from the Catoctin basalts, feeder dikes and sills. The study reveals three ancient direction of magnetization. The youngest, C component, fails the fold test and yielded a characteristic in situ direction of D=147¿, I=+44¿ (k=21, α95=9¿). The corresponding paleopole falls along the Middle Ordovician segment of the Laurentian APWP and we consider this component to be the result of a Taconic remagnetization. The second component, the B component, is carried by hematite, exhibits dual-polarities and passes a fold test. The tilt-corrected B component characteristic direction is D=92¿, I=+17¿ (k=16, α95=13¿). The corresponding paleopole at 4¿S, 193¿E falls near a well-established Late Cambrian (505 Ma) pole for Laurentia, and we consider this component to be a remagnetization during a Late Cambrian tectonic event in the central Appalachians. The third component isolated in the Catoctin basalts, the A component yields a tilt-corrected mean of D=68¿, I=+84¿ (k=59, α95=9¿). This component passes a fold and reversal test. A suite of samples was collected from two Catoctin feeder dikes and surrounding country rocks that yield a positive baked contact test. The A pole at 43¿S, 128¿E falls significantly away from previously proposed Vendian poles for Laurentia. A reevaluation of previous paleomagnetic studies from coeval rock units reveals similarly steep directions and leads us to propose a new APWP. This new APW track indicates that Laurentia was located near the pole during the interval 615--580 Ma and drifted rapidly (16 cm yr-1) toward its Late Cambrian equatorial position. |
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Keywords
Geomagnetism and Paleomagnetism, Paleomagnetism applied to tectonics (regional, global), Tectonophysics, Plate motions—general, Tectonophysics, Continental tectonics—general, Tectonophysics, Dynamics of lithosphere and mantle—general |
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American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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