Topological Charge Accumulation and Coalescent Fracture Avalanche: An Endogenous Topological Mechanism for the Late Devonian Kellwasser Mass Extinction

 The Frasnian–Famennian (Kellwasser) crisis is the only one of the Big Five extinctions for which no synchronous, high-energy external trigger has been dated to its level. Here I argue that this absence is not a dating deficiency but a structural fact: the crisis is an endogenous topological collapse of a slowly stressed reefal–pelagic biosphere. Three observational regularities converge on this reading: (i) the marine crisis is a ≥25 Myr history of at least three asynchronous extinction peaks (Taghanic, Lower Kellwasser, Upper Kellwasser) rather than a single boundary event; (ii) metazoan reef frameworks died in most basins before the Frasnian–Famennian boundary and, in the Canning Basin, in sections with no coeval anoxia; and (iii) the Lower and Upper Kellwasser horizons carry nearly identical geochemical signatures ( \((\delta^{13} C ~ 4 \%\) excursions, \(\delta^{18} O ~+1 \%\) O ~+1‰ steps, 5–7 °C cooling) but produced drastically different biotic outcomes. I interpret this near-identical forcing / wildly different response as the signature of a fold (saddle-node) bifurcation: ecological topological charge accumulated as modular reefal fragmentation over millions of years, while slow forcing (rooted-plant weathering, eustatic oscillation) only lowered the activation barrier until a coalescent fracture avalanche propagated. Food-web modelling of the Permian–Triassic crisis shows taxonomic loss precedeing ecosystem-stability collapse by ~61 kyr, providing a quantitative template. I state falsifiable predictions: autocorrelation/variance early-warning signals should rise across the 400–450 kyr Lower–Upper Kellwasser interval, and a reef-community order parameter should converge to a universal constant near criticality.