The Andaman Islands form part of the outer-arc accretionary sedimentary complex belonging to the Andaman–Sumatra active subduction zone. The islands are characterized by thick cover of Neogene sediments along with exposed ophiolite rocks at few places. A regional magnetic survey was carried out for the first time over the Andaman Islands with a view to understand the correlation of anomaly signatures with surface geology of the islands. The residual total field magnetic anomaly maps have revealed distinct magnetic anomalies having intermediate to high amplitude magnetic signatures and correlate with the areas over/close to the exposed ophiolite rocks along the east coast of north, middle and the south Andaman Islands. The 2D modelling of magnetic anomalies along selected E–W profiles across the islands indicate that the ophiolite bodies extend to a depth of about 5–8 km and spatially correlate with the mapped fault/thrust zones.
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The authors are grateful to the Department of Science and Technology (DST), New Delhi for the financial support under the research project (ESS/16/346/2008) sanctioned to Prof. M Radhakrishna, IIT Bombay. They also thank Mr. Rishikesh, Mr. Rajubabu and the officers of the DST, Andaman & Nicobar Administration, for the excellent logistic support. Critical comments from two anonymous reviewers helped to improve the manuscript.
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SUBBA RAO, P.B.V., RADHAKRISHNA, M., HARIPRIYA, K. et al. Magnetic anomalies over the Andaman Islands and their geological significance. J Earth Syst Sci 125, 359–368 (2016). https://doi.org/10.1007/s12040-016-0660-7
- Magnetic survey
- magnetic anomalies
- Andaman Islands
- Andaman–Sumatra Arc
- northeast Indian Ocean