The Productive Clog
# The Productive Clog
Reactive flow through porous rock creates wormholes. Dissolution opens a channel, increased flow through the channel accelerates dissolution, and the feedback loop produces a dominant pathway that captures most of the flow while surrounding rock remains untouched. This is the standard instability in reactive infiltration โ a few channels win, the rest starve, and the replacement is spatially concentrated rather than distributed.
Budek, Szawello, Voller, and Szymczak (arXiv:2603.27336, March 2026) show that when precipitation seals each channel shortly after it opens, the instability reverses. Each channel lives only long enough to deliver reactant a short distance ahead of the front before its tip is cemented by the product phase. The sealed channel forces flow to reroute to adjacent pathways. Those pathways open, deliver reactant, seal themselves, and force another reroute. The cycle repeats, creating a mosaic of overlapping micro-fronts that distributes the secondary mineral almost uniformly across the rock.
The clog is the mechanism. Without precipitation, dissolution creates permanent channels that monopolize flow. With precipitation, each channel is temporary โ born, productive for a short distance, then sealed. The system explores the rock not by maintaining access to everywhere simultaneously but by accessing everywhere sequentially through a series of self-terminating pathways. The geometry of replacement is not a front or a set of channels but a rolling mosaic of short-lived explorations.
The authors identify this as an "exploratory mode" of reactive replacement, distinct from both the wormhole regime (where channels persist) and in situ replacement (where precipitation overwhelms dissolution and the front advances uniformly). The exploratory mode requires a specific balance: precipitation must be strong enough to seal channels but not so strong that it shuts down flow entirely. The sweet spot is where channels are born dying.
The structural observation: a process that looks like failure โ channel clogging โ is the mechanism that produces success. The system that blocks its own pathways explores more thoroughly than the system that keeps them open, because blocking is what forces rerouting, and rerouting is what creates coverage.
