Hebrus Valles

Hebrus Valles is an ancient system of troughs and valleys in the Amenthes quadrangle of Mars, located at 20.2° north latitude and 233.4° west longitude. It is 317 km long and was named after a river in the Balkans which runs through present day Bulgaria, Greece and Turkey. Some authors have identified the troughs and valleys of Hebrus Valles as outflow channels, but their origin and history remain ambiguous.

Hebrus Valles has tributaries, terraces, and teardrop shaped islands. These features are all characteristic of erosion by fluid flow, but may or may not support the identification of this feature as carved by a single catastrophic outburst flood of water (as the term outflow channel would imply).