Pleistocene Upheaval: Splitting Indo-Brahma River

The splitting of the ancient Indo-Brahma river into the Indus, Ganga, and Brahmaputra drainage systems is attributed to the Pleistocene upheaval.

Geological Event Explanation

The Pleistocene epoch saw significant tectonic activity and landform changes in the Indian subcontinent. This period of geological uplift, particularly in the Himalayan region, is known as the Pleistocene upheaval.

• The crustal movements and uplift associated with this upheaval altered the landscape dramatically.
• This uplift created gradients and barriers that disrupted the flow of the pre-existing large river system (Indo-Brahma).
• Consequently, the river's course was fragmented, leading to the formation of separate drainage basins for the Indus, Ganga, and Brahmaputra rivers.

Other options like river capture, volcanic eruptions, or glacial melting, while significant geological processes, are not considered the primary cause for this specific large-scale river system division.