JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 99, NO. B3, PAGES 4625--4641, MARCH 10, 1994 Paleomagnetismof the Catoctin volcanic province: A new Vendjan-Cambrian apparent polar wander path for North America Joseph G. Meert and Rob Van der Voo Department of Geological Sciences, University of Michigan,Ann Arbor Troy W. Payne Department of Environmental Studies, University of Virginia, Charlottesville The Vendian/Cambrian segment of the Lauretian 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 570ñ 35 Ma (Rb-Sr) and 597 ñ 18 Ma (U-Pb) and therefore presented an excellent palcomagnetic 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 revealed three ancient directions of magnetization. The youngest, C component, fails the fold test and yielded a characteristic in situ direction of D=147 ø, I = +44 ø (k=21, c•95=9ø). The corresponding palcopole falls along the Middle Ordovician segment of the LaurentJan 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 ø , I= +17 ø (k=16, c•95=13ø). The corresponding palcopole at 4øS, 193øE 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 ø, I = +84 ø (k=59, ot95=9ø). 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 43øS, 128øE falls significantly away from previously proposed Vendian poles for Laurentia. A reevaluation of previous palcomagnetic 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. INTRODUCTION The Wilson cycle of continental assembly and dispersal [Wilson, 1966] is one of the fundamental tenets of plate tectonic theory. The assembly of Pangea in the late Paleozoic and its subsequent Mesozoic dispersal is the best example of global scale, Wilson cycle, tectonism. It is postulated that an earlier aggregation of continental landmasses occurred during the late Proterozoic [Dalziel, 1992; Hoffman, 1991; Piper, 1987; Bond et al., 1984; Piper, 1982]. The assembly and dispersal of this supercontinent, recently called Rodinia Copyright 1994 by the American Geophysical Union. Paper number93JB01723. 0148- 0227/94/93JB-01723505.00 [McMenamin and McMenamin, 1990], coincided with major changes in biological evolution, seawater chemistry and, by inference, palcoclimate. Most of the arguments favoring Rodinia were based on geologic evidence because the paleomagnetic evidence was considered of insufficient quality to provide rigorous tests of continental configurations [Van der Voo and Meert, 1991]. Nevertheless, paleomagnetism offers the only quantitative tool for determining pre-Mesozoic plate motions and plate configurations. Laurentia occupied the central part of Rodinia, and detailed knowledge of its paleogeographic history during the Vendian will provide the initial framework for the paleogeography of the surrounding landmasses. The Vendian-Early Cambrian (650-540 Ma) portion of the Laurentian apparent polar wander 4625