Paleomagnetism of the Upper Ordovician Juniata Formation of the central Appalachians revisited again

Miller, John D.; Kent, Dennis V.

Two components of magnetization were isolated in the Upper Ordovician Juniata Formation sampled in the area of the Pennsylvania salient. The thermally distributed, reversed polarity B component was most likely acquired during Alleghenian deformation, and although it is poorly grouped, it is similar to other Appalachian synfolding magnetizations. The pre-Alleghenian age C magnetization is entirely of normal polarity and shows a difference in declinations between the mean magnetizations isolated on the northern and southern limbs of the salient of 24° ± 23°. This anomaly is consistent with the sense and magnitude of declination anomalies observed in pre-Alleghenian magnetizations isolated in other throughgoing Appalachian red beds of Silurian, Devonian, and early Carboniferous age. The mean inclination of -44.7° suggests a paleolatitude of about 26°S for the central Appalachians in the Late Ordovician. This paleolatitude fits a trend of southward motion of North America from the Ordovician to the Early Devonian, followed by northward drift through the remainder of the Paleozoic.

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Also Published In

Journal of Geophysical Research

More About This Work

Academic Units
Lamont-Doherty Earth Observatory
Biology and Paleo Environment
Published Here
August 30, 2011