Rifting of mature oceanic lithosphere at Chagos Bank, central Indian Ocean

Rifting of mature oceanic lithosphere at Chagos Bank, central Indian Ocean

T. J. Henstock and T. A. MinshullSouthampton Oceanography Centre

~25 km thick 49 Ma oceanic crust focused extension cf diffuse compression ~1.5 km deep rift valley active seismicity IRIS station on Diego Garcia and fixed CTBT hydrophones nearby

Bathymetry and gravity across rift valley

Crustal thinning underlies bathymetric trough in some profiles, whilst in others an offset between the thinning and the trough is required

Possible explanation from rheological models

Predictions for 49 Ma oceanic lithosphere assuming oceanic crust behaves as dry diabase and mantle as dry duniteThick crust => lower crustal flowThin crust => single crustal layer