Eberswalde (crater) - Eberswalde Delta

Eberswalde Delta

The crater contains inverted relief, an exhumed delta formed by the flow of a liquid, most likely water. The series of valleys leading into the delta "drain" an area of approximately 4000 km². The surface area of the delta is 115 km², measuring 13 km by 11 km. The delta was discovered by Michael Malin and Kenneth Edgett of Malin Space Science Systems through imagery taken by the Mars Global Surveyor in 2003.

The delta also provides unambiguous evidence that some Martian sedimentary rocks have been deposited in a liquid. The meandering of the channels provides evidence to support this. Additional sediments were deposited on top of the delta, burying it. The deposits in the channels formed sedimentary rock. As the surrounding softer sediments were eroded away, the delta was exhumed, but inverted.

Based on an estimate by Moore et al. in 2003 of flow volume to the crater at 700 m3/s, it is estimated that it would take twenty years to completely fill the crater, ignoring evaporation and infiltration. However, this is unlikely because it is hypothesized that the delta was not formed in a permanent lake but rather a series of short lacustrine episodes on the order of years. This suggests that the Martian climate at the Noachian epoch time of formation was characterized by a series of short, wet spells rather than a sustained wet climate.