Intrusion‐Induced Forced Folding Model for the Origin of Séítah Formation Domes on the Jezero Crater Floor, Mars

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Abstract The JPL rover Perseverance's investigations of Jezero crater's floor reveal that the ultramafic Séítah formation and the overlying mafic Máaz formation are deformed into a broad, low‐amplitude structural dome. Mastcam‐Z stereo images processed into digital outcrop models, together with RIMFAX ground‐penetrating radar profiles, were used to reconstruct the three‐dimensional stratal geometry of both units along a SW–NE transect across a southern domain of the dome called south Séítah. Measurements from 3‐D reconstructions show a progression from sub‐horizontal layers in the central parts of the dome to dips <20° away from the dome on its flanks, with Máaz and underlying Séítah layers dipping concordantly. RIMFAX profiles and imaging around the dome confirm that limb dips are continuous into the subsurface and form a flat‐crested composite quaquaversal fold structure. Séítah rocks in the fold core are up to 17 m higher than adjacent Máaz lava flows, despite stratigraphically underlying them, a relationship attributed to structural uplift. Fold geometry, wavelength (∼1 km), and amplitude (∼30–50 m), match models of forced folding produced by inflation of shallow igneous intrusions. The most likely cause is the emplacement of a sill or laccolith beneath the crater floor, generating elastic bending of the overlying layers. This intrusion‐driven uplift explains Séítah's elevated position, constrains the deformation history of Jezero's crater floor units post‐emplacement of the Séítah and Máaz formations, and supports a significant role for shallow magmatic intrusion in shaping intracrustal structures on Mars.

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