The large-scale landscapes in SW Scandinavia and in SW India are the result of two episodes of Neogene uplift

Peninsula India and Scandinavia are elevated passive continental margins (EPCMs) characterized by asymmetric relief with high mountains in the west and a gentle slope towards lowlands in the east.

New AFTA data from southern India reveal major Phanerozoic episodes of cooling, reflecting exhumation. Here we focus on the early Miocene episode possibly related to the hard India-Asia collision (van Hinsbergen et al. 2012). The Miocene exhumation resulted in a low-relief landscape; e.g. the Karnataka and Mysore plateaus (Gunnel and Fleitout, 1998) with residual regions of higher ground (e.g. Palani Hills). Today, these plateaus reach an elevation of 1 km along the coast of SW India, sloping towards the east. The Miocene peneplains were graded towards the base level of the adjacent ocean (Green et al. 2013), and therefore reached their present elevation after their formation. Thick piles of Pliocene sediments off SW India (Campanile et al. 2008) suggests that this happened during the Pliocene.

Richards et al. (2016) studied river profiles in Peninsula India and concluded that the regional tilt grew since 25 Ma, maintained by sub-lithospheric processes. However, we find that the relief is the result of two episodes: 1) Miocene peneplanation related to far-field stress. 2) Late Neogene, asymmetric uplift driven by sub-lithospheric processes.

We identified a similar development in SW Scandinavia, where two Neogene episodes of uplift and erosion define main features of the relief (Japsen et al. 2018): 1) Early Miocene uplift leading to formation of the Hardangervidda peneplain (possibly related to the hard India-Asia collision). 2) Uplift beginning in the Pliocene, raising Hardangervidda to its present elevation at 1.2 km. Pliocene uplift raised margins around the NE Atlantic with maximum elevations reached close to Iceland. This suggests support from the Iceland Plume due to outward-flowing asthenosphere extending beneath the conjugate margins (Rickers et al. 2013; Japsen et al. 2024). 
Lithospheric as well as sub-lithospheric processes appear to shape main features of EPCMs.

Campanile et al. 2008. Basin Research. Green et al. 2013. GEUS Bull. Gunnell, Fleitout 1998. ESPL. Japsen et al. 2018. JGSL. Japsen et al. 2024. ESR. Richards et al. 2016. G cubed. Rickers et al. 2013. EPSL.