Biblis Tholus

Biblis Tholus is an extinct Martian volcano, 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 kilometers (110 mi) long and 100 kilometers (62 mi) wide, rising about 3 kilometers (1.9 mi) 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.[2] The caldera is 53 kilometers (33 mi) in diameter and four kilometers (2.5 miles) in depth.