Magnetic anomalies across the southern Central Indian Ridge: evidence for a new transform fault

Abstract

Bathymetric and magnetic studies along seven northeast-southwest profiles across the Central Indian Ridge segment between latitudes 18 and 22°S and longitudes 66 and 69°E reveal a northwest-southeast trending median valley, associated with a broad and high-amplitude magnetic anomaly (the central anomaly) along the ridge crest. A series of linear magnetic anomalies parallel to the ridge are identified as sea-floor spreading lineations 2,2A,3,3A and 4. A half spreading rate of 2.2 cm y^-1 is estimated for the last 10 Ma. The ridge jump between the anomalies 2-2A (approx. 2.5 Ma) and a new left lateral transform fault offsetting the ridge axis about 50 km are indicated to explain the magnetic pattern.