  Chaos terrains are characterized by disruption of preexisting surfaces into
irregularly arranged mountain blocks with a chaotic appearance. Several models
for chaos formation have been proposed, but the formation and evolution of this
enigmatic terrain type has not yet been fully constrained. We provide extensive
mapping of the individual blocks that make up different chaos landscapes, and
present a morphological comparison of chaotic terrains found on Pluto,
Jupiter's moon Europa, and Mars, using measurements of diameter, height, and
axial ratio of chaotic mountain blocks. Additionally, we compare mountain
blocks in chaotic terrain and fretted terrain on Mars. We find a positive
linear relationship between the size and height of chaos blocks on Pluto and
Mars, whereas blocks on Europa exhibit a flat trend as block height does not
generally increase with increasing block size. Block heights on Pluto are used
to estimate the block root depths if they were floating icebergs. Block heights
on Europa are used to infer the total thickness of the icy layer from which the
blocks formed. Finally, block heights on Mars are compared to potential layer
thicknesses of near-surface material. We propose that the heights of chaotic
mountain blocks on Pluto, Europa, and Mars can be used to infer information
about crustal lithology and surface layer thickness.
