Tectonic Evolution of a Sedimented Oceanic Transform Fault: The Owen Transform Fault, Indian Ocean

The Owen Transform Fault (OTF) connecting the Sheba and Carlsberg spreading ridges in Indian Ocean currently forms active plate boundary between India Somalia plates. This 330-km-long transform fault is by far longest along India-Somalia its valley buried under thick distal turbidites of Indus Fan with total thickness ranging from 1000 to > 5000m. A new set seismic reflection multibeam bathymetric data reveals remarkable transpressive structures entire length recorded as folds sedimentary cover, eruption mud at seafloor, thrusts young oceanic lithosphere. Based on a regional time-calibration reflectors, we show that sediments (post 8.6 Ma) period tectonic quiescence until onset event around 1.5 − 2.4 Ma relate minor change kinematics not captured magnetic anomalies. regime still based compressive earthquakes deformation most recent sediments. Transpression resulted formation proto-median ridge coeval propagation tip Ridge into Somalian plate. These features are typically encountered many other faults but rarely their very early stage.