Isostasy and crustal structure of the Chagos–Laccadive Ridge, Western Indian Ocean: Geodynamic implications

Journal of earth system science

Unnikrishnan P^2¹  Sreejith K M^1² 

[1] Department of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.^2;Geosciences Division, Space Applications Centre, Ahmedabad 380 015, India.^1

关键词: Chagos–Laccadive Ridge;    isostasy;    Effective Elastic Thickness;    underplating;    crustal structure;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

The Chagos–Laccadive Ridge (CLR), a prominent linear aseismic ridge in the Western Indian Ocean is believed to be a trace of the Reunion hotspot. In order to understand the mode of emplacement of this ridge and the nature of the underlying crust, we carried out three-dimensional (3D) flexural modelling and coherence analysis of satellite-derived gravity and bathymetry data along the ridge. The analysis revealed variations in Effective Elastic Thickness ($T_{\rm{e}}$) along the CLR. While the northernmost part of CLR is associated with low $T_{\rm{e}}$ of 3 km with a subsurface to surface loading ratio ($f$) of 1, towards the south, the Maldive Ridge and the Chagos Bank have a fairly uniform $T_{\rm{e}}$ of 8–10 km with a very low loading ratio $f$ of 0.1–0.2. We consider the Laccadive Ridge as a continental sliver possessing underplated magmatic rocks caused by the Reunion hotspot volcanism. The Maldive Ridge and the Chagos Bank appear to have emplaced on a lithosphere of intermediate strength possibly on the flanks of the Central Indian Ridge.

【 授权许可】

CC BY