A clustering of paleomagnetic poles for rock units of mid-Paleozoic (ca. 400 Ma) age in eastern New England indicates that a variety of lithologic types may be used to obtain virtual geomagnetic poles (VGP's) in an igneous–metamorphic terrain. These rock types include chilled margins of basaltic dikes or narrow dikes, hydrothermal alterations such as epidote veinlets, mafic rocks reset by low-grade metamorphism, and hypabyssal igneous bodies, particularly where there is evidence of hydrothermal activity.The results suggest the approach to be followed to obtain valid VGP's in similar geological belts in the Precambrian. The remanence directions in Devonian and Mississippian rock units in eastern Massachusetts and southern and northern Maine are close to other determinations of similar age within the Maritime block, demonstrating the potential usefulness of the procedures.

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