1991 Articles

Tectonic Implications of a Remagnetization Event in the Newark Basin

Witte, William K.; Kent, Dennis V.

The Newark basin red beds contain a secondary magnetization (the B component) acquired during the Middle Jurassic after the 5°-20° basin-wide northwesterly dip was imparted to the strata of the basin and after most, if not all, of the limb rotation in the Jacksonwald syncline. The B component magnetization was most likely related to the same hydrothermal event which evidently remagnetized many of the igneous intrusions in the basin and reset their K/Ar systems at 175 Ma. The remagnetization of the red beds occurred over a few million years and was approximately coincident with the transition from continental rifting to seafloor spreading in the adjacent North Atlantic. The B component magnetization direction yields a paleomagnetic pole at 74°N, 96°E (K = 63, A_95 = 2.6°, N = 50 sites) after structural correction for 1/3 of the Jacksonwald folding and none of the regional tilt. This pole supports recent evidence for a high-latitude model of Jurassic apparent polar wander for North America.