In the southern hemisphere, there is a canyon running north-to-south, about 10*S through about 75*S lattitude. The chasm is deepest at about 60*S latitude, where a deep crevasse connects it to volcanic and seismic activity. Frequent gaseous expulsions from the planet's sulfuric core expel material -- usually a brownish sludge which runs off from the chasm walls -- out of the depths.

TLDR: The planet has a buttcrack.