Plate Reconstruction: Mathematical-Physical Framework and Selected Case Studies

Engen, Ø., 2000, Plate reconstruction; mathematical-physical framework and selected case studies [term paper]: Oslo, University of Oslo, 25 p. Literature treating plate reconstructions has been examined. On this background both the theoretical framework and practical reconstruction procedures are presented, along with case studies from the North Atlantic, the South Atlantic, and the Indian Ocean. The physical framework is based on the assumption of rigid lithospheric plates moving on a viscous asthenosphere. If one plate is held fixed and no internal deformation is assumed, it is possible to treat plate motion in a quantitative manner. A mathematical framework is then needed. Euler’s fixed-point theorem states that motion on the Earth’s surface can always be described as a rotation about a central axis. There are two types of rotations: Finite rotations bring two points on adjacent plates into coincidence, regardless of the actual drift path between them; infinitesimal rotations describe each minute segment of a flow line. Thus, a plate reconstruction has to find rotation vectors given by poles and rotation angles that can accommodate the observed plate motion. Pitman and Talwani (1972) delineate a practical reconstructio