Paleomagnetic poles for the Jurassic Corral Canyon sequence and Glance Conglomerate in southern Arizona have been used to construct apparent polar wander (APW) paths for the North American plate, but they are controversial and conflict with higher-latitude poles from New England. Lower Jurassic dacites and ash flow tuffs of the Mount Wrightson Formation in the Santa Rita Mountains were initially sampled to provide an additional paleopole for southern Arizona. These rocks, however, have a predominantly reversed-polarity characteristic magnetization (in situ, I=-47¿, D=154¿, α95=9¿) which is statistically indistinguishable from that for the nearby latest Cretaceous Elephant Head pluton (I=-48¿, D=165¿, α95=8¿). Although magnetizations of both polarities are observed in the ash flow tuffs, they are mostly carried by hematite, and dual polarity components are observed within some specimens.

Moreover, widespread mineralization and a K-Ar age of ~67 Ma for altered rocks of the Mount Wrightson Formation imply that these rocks were subjected to a prolonged episode (greater than one polarity interval) of low-temperature alteration and remagnetization. Middle Jurassic ash flow tuffs of the Corral Canyon sequence in the Patagonia Mountains to the south have a similar geologic setting: They are exposed along strike amid mineralized rocks on the eastern flank of a mountain range cored by Paleocene intrusions. Hematite is also the dominant remanence carrier in most of the Corral Canyon sequence, and its predominantly normal-polarity direction (in situ, I=51¿, D=326¿, α95=9¿) is indistinguishable from that for the nearby Patagonia Granodiorite (I=49¿, D=342¿, α95=8¿). Rocks of the Corral Canyon sequence therefore are likely remagnetized as well. Problems also exist with the Glance Conglomerate pole. These rocks are situated within a caldera structure and have been potassium metasomatized. This potassic alteration could have occurred shortly after emplacement or at a later time, postdeformation. The low-latitude Jurassic APW path for North America and J-2 cusp therefore are not well supported and may need revision. ¿ American Geophysical Union 1994