Rifting assisted by shear heating and formation of the Lomonosov Ridge

We suggest that thermo-mechanical feedback between shear heating and temperature-dependent viscosity in continental zones of oblique extension has the potential to significantly weaken the lithosphere and facilitate subsequent rapid breakup. We perform thermo-mechanical experiments of strike-slip and coeval but longer lasting extension using the finite element method. The style of rifting in our model depends mainly on the efficiency of shear heating which, in turn, depends on the magnitude of lithospheric stresses and strain rates. We develop and apply a numerical model to explain the formation of the Lomonosov Ridge microcontinent. Our proposed model provides a physically consistent mechanism for the detachment of the Lomonosov Ridge from the Barents–Kara Sea margin at 68–56 Ma. The narrow rift mode predicted by the numerical model is supported by the crustal structure of conjugate passive margins of the Eurasia Basin.

• Style of continental rifting depends on the efficiency of shear heating.
• Narrow rifted margins may develop by oblique extension assisted by shear heating.
• Strike-slip deformation facilitated formation of the Lomonosov Ridge 68–56 Ma.