RELATIONSHIP BETWEEN RIFT SPREADING AND LONGITUDINAL PROPAGATION RATES

Abstract

Work of recent years has convincingly shown that virtually all rift structures, whether continental or oceanic, expand in two directions simultaneously. Thus, the rift undergoes not only transverse extension (spreading), but also propagates, in a direction roughly perpendicular to the spreading, into the older lithosphere, breaking it up as the fault advances. Also, it is well known that the rates of these two components of expansion are not steady. We have analyzed rift generation in some regions where the evidence for advancement of oceanic rifts into continents in Recent or ancient times is strong. The rates of transverse extension (spreading) were estimated by the traditional approach, computing the distance between the pairs of identifiable magnetic anomalies of the same age.