Abstract
We present results derived from a seismic refraction experiment and gravity measurements about the crustal structure of southern Sri Lanka and the adjacent Indian Ocean. A P-wave velocity model was derived using forward modelling of the observed travel times along a 509 km long, N-S trending profile at 81°E longitude. Our results show that the continental crust below southern Sri Lanka is up to 38 km thick. A ~ 65 km wide transition zone, which thins seawards to ~7 km thickness, divides stretched continental from oceanic crust. The adjacent, 4.7 to 7 km thick normal oceanic crust is covered by up to 4 km thick sediments. The oceanic crust is characterized by intra-crustal reflections and displays P-wave velocity variations, especially in oceanic layer 2, along our profile. In the central part of the profile, the uppermost mantle layer is characterized by normal P-wave mantle velocities of 8.0–8.1 km/s. At the southern end of the profile, unusual low upper mantle seismic velocities, ranging from 7.5 to 7.6 km/s only, characterize the uppermost mantle layer. These low upper mantle velocities are probably caused by partially serpentinized upper mantle. At even greater depths the upper mantle layer is characterized by velocities of 8.3 km/s on average. The type of margin along our profile is difficult to identify, since it is characterized by features typical for different types of margins.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
