Spreading history of the Arabian Sea: Some new constraints

Abstract

Based on a new identification of magnetic anomalies, additional constraints are provided on the two episodes of spreading history of the Arabian Sea. Commencing at A27, the older phase ended at A21 and sprading of the younger phase started shortly before the formation of All. The hiatus between these spreading spisodes, characterizEd. by a magnetic quiet zone., was much shorter (18 x 10 sup(6) yr) than previously believed. After spreading restarted, the younger phase continued at a very slow rate (0.7 cm/yr) till anomaly 6A. This rate increased between anomalies 5C and 6A and the spreading continued to the present at about 1.2 cm/yr. The data also enabled identification of a new NE-SW trending fracture zone, which right laterally offsets the entire magnetic anomally sequences 1 through 11 across the Carlsberg Ridge by about 50 km