Geology
Ithaca Chasma is a giant trough system about 3 km deep and approximately confined to a great circle running through the poles of Tethys. It is approximately concentric with Odysseus impact crater—a pole of Ithaca Chasma lies only approximately 20° from it.
The chasma has a rather complex structure consisting of two narrow branches towards the south. Its exterior walls are made of multiple sub-parallel scarps and terraces. At some places the chasma has a rim standing as high as 0.5 km about the surrounding cratered planes. Its width varies from only a few kilometers at some places to more than 100 km.
The age of Ithaca Chasma is estimated to be either 4.0 or 0.4–3.3 billion years depending on chosen impact chronology. The crater counts indicate that the chasma is slightly younger than Odysseus crater and much younger than the cratered plains.
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