Triton's western hemisphere consists of a strange series of fissures and depressions known as "cantaloupe terrain" because of its resemblance to the skin of a cantaloupe melon.
Although it has few craters, it is thought that this is the oldest terrain on Triton.
It probably covers much of Triton's western half.

Cantaloupe terrain, which is mostly dirty water ice, is only known to exist on Triton.
It contains depressions 30–40 km in diameter.
The depressions (cavi) are probably not impact craters because they are all of similar size and have smooth curves.
The leading hypothesis for their formation is diapirism, the rising of "lumps" of less dense material through a stratum of denser material.
Alternative hypotheses include formation by collapses, or by flooding caused by cryovolcanism.
Triton's western hemisphere consists of a strange series of fissures and depressions known as "cantaloupe terrain" because of its resemblance to the skin of a cantaloupe melon. Although it has few craters, it is thought that this is the oldest terrain on Triton. It probably covers much of Triton's western half.
Cantaloupe terrain, which is mostly dirty water ice, is only known to exist on Triton. It contains depressions 30–40 km in diameter. The depressions (cavi) are probably not impact craters because they are all of similar size and have smooth curves. The leading hypothesis for their formation is diapirism, the rising of "lumps" of less dense material through a stratum of denser material. Alternative hypotheses include formation by collapses, or by flooding caused by cryovolcanism.
Triton (moon)