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Underground water channels preserve ancient climate records in their shape

Water reshapes Earth through slow, powerful erosion, carving intricate landscapes like caves and pinnacles in soluble rocks such as limestone. An international team from the Faculty of Â鶹ÒùÔºics at the University of Warsaw, the University of Florida, and the Institute of Earth Sciences in Orléans has discovered that vertical channels, known as karstic solution pipes, preserve a record of Earth's climatic history.

Their study, in Â鶹ÒùÔºical Review Letters, reveals that these pipes evolve with time into an invariant shape, a fixed, ideal form that remains unchanged as the pipes deepen, encoding ancient rainfall patterns.

Using microfluidic experiments, the team mimicked this process in miniature, etching water into channels within gypsum-lined cells. "We observed something striking," says StanisÅ‚aw Å»ukowski, pursuing Ph.D. at the Faculty of Â鶹ÒùÔºics of the University of Warsaw and Université Paris Cité, the first author of the paper.

"From a chaotic start, only a few channels survived, each settling into a stable, invariant shape that grew deeper without changing form. This mirrors the behavior of karstic pipes in nature."

Deriving the mathematical formula for this shape was complex. "Capturing the invariant form required sophisticated mathematical tools, blending fluid dynamics and reactive transport to model how groundwater, driven by rainfall, shapes these pipes," says Prof. Piotr Szymczak from the Faculty of Â鶹ÒùÔºics, University of Warsaw, the corresponding author.

"The formula reveals how heavy precipitation accelerates groundwater movement, forming elongated pipes that record in their shape past rainfall conditions."

Deciphering nature's plan

By studying these shapes, scientists can reconstruct Earth's climatic past. Understanding these patterns is also crucial for predicting how water moves through underground reservoirs, which has implications for everything from groundwater management to COâ‚‚ storage and even oil recovery.

This study is part of a broader effort to understand how simple physical laws give rise to complex natural structures. Just as snowflakes and river deltas follow mathematical rules, so too do the silent, hidden processes of rock dissolution. The discovery of an invariant shape for dissolution fingers is a step toward deciphering nature's secret blueprint, one drop of water at a time.