Paleomagnetic results from the Mauch Chunk Formation: A test of the origin of curvature in the Folded Appalachians of Pennsylvania

Specimens of red siltstone were collected at twenty-five sites in the Upper Mississippian Mauch Chunk formation of Pennsylvania. The sites were so distributed as to test whether the curve in the folded Appalachians was formed after the magnetization of the beds or whether the orginal geosyncline in Mississippian time was curved in plan. All specimens were partially demagnetized to isolate the stable component. When the beds are rotated back into a horizontal position, the stable components show a decrease in the scatter between the sites, indicating that the direction of magnetization was acquired before the folding of the Appalachians. The directions of demagnetization were found to be the same around the curve of the Appalachians, apparently ruling out their horizontal rotation after the acquisition of their stable magnetization. The pole position calculated from the Mauch Chunk is at 43°N, 127°E with a Δp = 3.1, Δm = 6.3. This pole position is in general agreement with other late Paleozoic poles.