I believe the Himalayas were originally the seabeds created by the fresh molten basaltic material that welled up from the mantle to fill the original hole in the Indian plate.

The Indian sub-continent has a major compressional border, as it pushed upwards into the larger continental plate. In conventional Plate-tectonics it is believed that these compressional fault lines exist between areas of the crust that have been moving towards each other over large distances, or at the points where huge ancient seafloors once existed but are now long subsumed back into the mantle by subduction. Traditionally, India is believed to have collided with Asia. But again, this is partly based on the reconstruction of the continents on a constant diameter.

On an expanding sphere the dynamics of compression and extension I believe would be quite different. The older stable shield areas around them, rather than moving together over greater distances, would remain in their relative original positions, but would collapse back onto themselves to retain an equilibrium while the sphere beneath them increases ( similar to 'isostatic rebound': 'ptss' ), thus creating compressional boundaries between them, pushing them upwards and buckling them into the huge fold mountain range.