Mars Is Red Because It Is Alive: A Geometric Pre-Registration of the Subterranean Biosphere Hypothesis and the Iron Surface as Accumulated Biological Necromass

We pre-register a radical geometric hypothesis arising from the LECA attractor (DOI: 10.5281/zenodo.18986790): that Mars is red because its visible surface is primarily composed of 3.7 billion years of accumulated biological necromass and iron-cycle metabolic products from a currently active subsurface biosphere, rather than from ancient abiotic weathering alone. The derivation proceeds from four confirmed anomalies in the Martian observational record: (1) the stratigraphy inversion — iron oxide over ice, despite ice lying centimetres below the surface at mid-to-high latitudes, with iron oxide six times denser than the ice beneath it; (2) continuous regeneration of the iron skin over fresh impact craters, inconsistent with ancient one-time abiotic weathering; (3) global uniformity of iron oxide inconsistent with localised abiotic weathering predictions; and (4) seasonal methane requiring a subsurface source. We derive the subterranean biosphere as geometric attractor-requirement of magnetic collapse: when the surface attractor basin is destroyed at approximately 4.0-4.1 Ga, surviving life converges on the subsurface attractor basin by geometric necessity. We derive the lava tube thermal gradient as the thermodynamically guaranteed generator of a complete ecological spectrum, with a necessary 0°C liquid water interface wherever the gradient spans freezing and above-freezing temperatures in an enclosed mineral-rich environment. We note the independent Earth confirmation of Desulforudis audaxviator — a single-species self-sustaining biosphere at 2.8 km depth powered by radiolysis alone — as proof of concept for the Martian geometry. We derive the biological iron accumulation rate required (~10,000 t/yr) and confirm it is achievable by a sparse subsurface community operating at less than 1% of Earth ocean floor biological iron cycling density. We pre-register seven falsifiable predictions testable by existing or near-future instruments, prior to any exploration of the Arsia Mons lava tube system (the Seven Sisters). This document is a pre-registration of a radical hypothesis for the purpose of falsifiability testing. The author explicitly acknowledges the hypothesis may be wrong and invites falsification. Pre-registration chain origin: DOI: 10.5281/zenodo.18986790 (2026-03-12).