Evolution of the Carlsberg Ridge between 60 and 45 Ma: Ridge propagation, spreading asymmetry, and the Deccan‐Reunion hotspot

Abstract

Despite the availability of numerous geophysical data, no convincing magnetic anomaly identification and structural map of a major part of the Arabian and eastern Somali Basins have been published to date. I propose a new interpretation of the available magnetic data based on the identification of ”tiny wiggles,” i.e., singular second‐order patterns of the magnetic signal. Only one fracture zone and a set of propagating rifts existed between the Owen Fracture Zone and the Chagos‐Laccadive Ridge between anomalies 26 and 20. At anomalies 26–25, at least two eastward propagating rifts are identified, while at anomalies 24–20, seven westward propagating rifts are confidently recognized. The major consequence of this systematic ridge propagation is a tremendous regional asymmetry: between anomalies 26 and 25, about 65% of the crust formed at the Carlsberg Ridge was accreted to the African Plate, while at anomalies 24–20, more than 75% benefited to the Indian Plate. I suggest that these asymmetries result from the relative position of the Carlsberg Ridge and the nearby Deccan‐Reunion hotspot, the ridge tending to remain near the hotspot.