Biblis Tholus

Biblis Tholus is an extinct Martian volcano located at 2.55°N, 235.62°W, one of two volcanoes near the center of the Tharsis volcanism. Along with Ulysses Tholus, it is almost midway between Olympus Mons and the Tharsis Montes. Biblis Tholus lies in the Tharsis quadrangle. It is approximately 170 km long and 100 km wide, rising about 3 km from its surroundings.

In the middle of the volcano is a caldera, named Biblis Patera, believed to have formed as the result of collapse of the magma chamber during eruptions of the volcano. The caldera is 53 km in diameter and four kilometers (2.5 miles) in depth.