1982 Articles

Paleomagnetism of Siluro-Devonian rocks from eastern Maine: Reply

Kent, Dennis V.; Opdyke, Neil D.

Roy's discussion of our paper covers two topics. First, he attempts to show on the basis of various statistical tests that the characteristic magnetizations we reported in the Hersey red beds and the Eastport Formation were acquired after tectonic tilting and represent what he refers to as an "orogenic" remanence. Second, he presents an interpretation of paleomagnetic data from eastern Appalachian rock units proposing that low paleoatitudes are in general derived from orogenic remanences of Devonian-Carboniferous age whereas the intermediate to high paleoatitudes are derived from older remanences. In reply, we argue that Roy's statistical methods may not be appropriate and nevertheless are not sufficient to demonstrate a post-folding origin of remanence and that the weight of evidence in fact favors remanence acquisition near the time of formation of the Siluro-Devonian rock units. Independent of the question of pre- or post-folding magnetization of these rock units, we find that the available paleomagnetic data from the eastern Appalachians do not support his model of a relatively simple paleolatitudinal progression with age for this area, but rather point to the results from Acadian (Devonian) intrusive rocks as anomalous for reasons that are not yet entirely clear.