Complex expressions of inverted and exhumed relief in central Utah, and some martian counterparts

Investigations of Jurassic fluvial architecture in central Utah during a three-month simulated Mars surface expedition have revealed a range of expressions of exhumed and inverted relief. They provide tests for prior interpretations of Jurassic fluvial architecture in the area. We propose a new category of exhumed or inverted relief that we term ghost channels. These are landscape ridges that have formed beneath former inverted or exhumed channels where the actual channel facies are no longer present. The formerly present erosion-resistant caps of channel fill have been removed by erosive processes such as parallel scarp retreat. We propose that, when recognised, ghost channels may enable far more complete mapping of former drainage patterns in both landscapes and eroding basins than previously possible. Finally we compare counterparts of these features on the surface of Mars.