Impact a part of the model
Ductile Solid Migration Tectonics (DSMT...I just made that up...) requires an overburden structural weakness. In the case of Gulf Coast Salt Domes, it's an intersection of faults. For the Canyonlands, it's the canyon itself; or, as earlier discussed, an impact in a favorable stratigraphy. Such is the case, I suggest, on Ceres. An impact over a localized deposit of a solid ductile material at the proper depth.
In some ways, it is this postulated heterogeneous stratigraphy that has me scratching my head.