Plate Motion Statistics and Relation of Propagation and Overlap for the Juan de Fuca Ridge

点击翻译按钮获取中文摘要

Lithospheric plates that compose the outer shell of the earth form by volcanic processes at mid-ocean ridges (spreading centers) where igneous material is added more or less symmetrically to each plate which borders on the mid-ocean ridge. This growth process is accompanied by relative motion between the two plates on either side of the ridge crest-motion that can be determined from a study of amgnetic anomalies observed at the sea surface over the mid-ocean ridge. Over a short period of geologic time ( few million years) this relative motion can be described in terms of rotation about a point (pole) that remains fixed to each plate. Over longer periods of time the motion is moe complicated and is accompanied by changes in the configuration of the mid-ocean spreading center, changes which are manifest as overlapping spreading centers and proagating rifts. %%% This project investigates the details of this process for the Juan de Fuca Ridge, a spreading center off the Washington- Oregon coast. Wilson plans to determine a revised rotation pole with confidence limits for motion of the Juan de Fuca plate with respect to the Pacific plate. In the process he will make computer modesl to demonstarate the development of overlapping spreading centers and propagating rifts. He will also attempt to determine over what interval the relative plate motion can be described in terms of a sample rotation.