Why do stable lands like the Western Ghats, Guiana Shield & the Drakensberg rise vertically? Scientists find answers

Sub: Geo

Sec: Geomorphology

Context:

A new study reveals that the splitting of continents can cause significant topological changes in distant stable lands, such as the formation of plateaus and escarpments (steep slopes).

Tectonic Movements and Lithosphere Thinning:

When tectonic plates move apart, the lithosphere, consisting of the upper mantle and crust, thins, leading to the splitting of a continent. During this process, steep coastal escarpments form at the rift margins, marking the transition between continents and oceans, while interior plateaus rise inland.

Impact on Cratons and Vertical Uplift:

The study explains why cratons, stable parts of continents like the Sahyadri hill range in the Western Ghats, eastern Brazil, and southern Africa, which are far from rift zones, experience vertical uplift.
This is due to a ‘deep mantle wave’ triggered by the continental breakup, which travels along the continent’s base and removes layers of rock, causing the continents to rise through a process called isostasy.

Climate Impact and Biodiversity

The formation of escarpments and elevated plateaus can lead to extreme erosion, which helps draw down carbon dioxide from the atmosphere.
Additionally, these topological changes create physical barriers that drive the formation of new species by forcing populations to adapt to different ecological niches.
The uplift of land by hundreds of meters to over a kilometre can either push plants out of their comfort zones or compel them to adapt to new climatic conditions. Researchers aim to determine if this process occurs globally in other continental regions.

Source: DTE