Mars Biosphere Collapse vs. Emergence: A Pre-Registered Geometric Prediction of the Complexity Gradient in the Mars Sedimentary Record Prior to Sample Return

A pre-registered geometric prediction concerning the directional ambiguity in the Cheyava Falls biosignature record. The Mars magnetic field loss (~4.0-4.1 Ga) and the Cheyava Falls deposition age (~3.8-4.1 Ga) are coincident within measurement error. This creates two mutually exclusive interpretations: biosphere emergence (predicts complexity increases with decreasing depth) or biosphere collapse (predicts complexity increases with increasing depth and age). The prediction is locked here before Mars sample return and is testable by the stratigraphic complexity gradient in the Jezero Crater subsurface record. Also presents the water attractor state cascade model (three chemical attractor states of planetary water chemistry), the two-axis LECA stabilisation model (independent nitrogen and oxygen destabilisation axes), and the ARM A morphological reference standard as the formal comparison target for Mars sample return material.