ROTATION ABOUT AN INCLINED AXIS - 3-DIMENSIONAL MATRICES FOR RECONSTRUCTING PALEOMAGNETIC AND STRUCTURAL DATA

We derive matrices for calculating the three-dimensional finite rotati on that restores a rigid block to its pre-displacement attitude. To us e this technique an initial horizontal bedding is assumed, and the fol lowing orientations must be known: the expected field orientation of m agnetization, the in situ orientation of the paleomagnetic vector and the bedding normal. The restoring rotation is decomposed into two conv enient steps, represented by rotation matrices, such that they restore the in situ paleomagnetic vector together with the tilted bedding nor mal to their original orientation. These auxiliary rotations combine a lgebraically to a single finite rotation from which an inclined axis a nd amount of rotation are obtained. We demonstrate this method by reco nstructing a distinct section of the Mount Sedom salt diapir (Dead Sea Rift Valley, Israel). Here, the conventional tilt correction that bri ngs the bedding to horizontal fails to position the paleomagnetic vect or in its expected orientation. Only a rotation of 125 degrees about a n axis which plunges 50 degrees southward can restore both bedding and magnetization to their expected orientations.