Earth Forests and the Sutlej

The “earth forests” of Zhada are not a forest in the botanical sense. They are steep formations cut into the sedimentary fill of a high basin, where ridges and gullies make the exposed layers look like a dense stand of stone trunks. The Sutlej River is central to that shape. A study in Earth Surface Processes and Landforms describes the Zhada Basin as an arid, low-relief basin that the Sutlej has deeply incised, exposing the basin fill in cliffs. What a visitor sees as a sculpted landscape is also a cross-section through a much older history of water, sediment, and changing drainage.

The researchers investigate a geological event known as drainage capture: a river network expands by taking in the waters of a neighboring basin. Their study reconstructs the Sutlej’s capture of the Zhada Basin during the Pleistocene, using river profiles, reconstructed paleotopography, and erosion measurements. The basin is about 23,000 square kilometres. The study estimates that capture-driven erosion removed roughly 2,010 cubic kilometres of sediment, with a broad uncertainty range. These are model-based estimates for a regional process, not measurements of a single cliff or a claim that the entire landscape appeared at once.

The authors estimate the capture at about 735,000 years ago, with an uncertainty of roughly 269,000 years, and argue that headward erosion was the primary driver in their model. That is a scientific reconstruction built from present-day topography and geological evidence, not a memory preserved in local oral history. It helps explain why the basin’s low, broad surfaces meet abrupt incised valleys. The study also notes that incision is ongoing in the river network. The cliffs therefore carry two scales at once: their visible edges invite a close look, while the explanation behind them reaches across hundreds of thousands of years and remains open to refinement as new data appear.

The sediment layers also preserve evidence that the basin once held a lake. The paper summarizes earlier work placing the beginning of its shrinkage around 3.5 million years ago, as the Indian summer monsoon weakened; other evidence in the upper formation points to shallow, saline water. These are prior interpretations cited in a modern geomorphology study, not a visible shoreline that can be read from one viewpoint. Still, they add a quiet dimension to the earth forests: the cliffs reveal a landscape that changed from lake and basin deposits to a river-cut valley. A walk among the ridges moves across the exposed pages of that transformation.