June 6, 2013
Mars Express Shows Off The Red Planet’s Flood History
Lee Rannals for redOrbit.com — Your Universe Online
Kasei Valles is one of the largest outflow channel systems on Mars and extends to about 1,800 miles and descends by 1.8 miles in altitude. The image taken by Mars Express spans 613 miles north-south (19—36°N) and 963 miles east-west (280—310°E). The channel begins beyond the southern edge of the image near Valles Marineris and empties into the vast plains of Chryse Planitia to the east.
The channel system splits into two main branches that hug a broad island of fractured terrain known as Sacra Mensa. It rises 1.2 miles above the channels that swerve around it.
"While weaker materials succumbed to the erosive power of the fast-flowing water, this hardier outcrop has stood the test of time," said ESA.
Further downstream the image shows how flood waters tried to erase the 62 mile-wide Sharonov crater by crumpling its southern rim. Many small streamlined islands form teardrop shapes rising from the riverbed around Sharonov.
In the region between Sacra Mensa and Sharonov, the mosaic features a detailed look downstream from the northern flank of Kasai Valles. When zooming into the valley floor, it begins to reveal small craters with dust "tails" seemingly flowing in the opposite direction to the movement of water. These craters were formed by impacts that took place after the catastrophic flooding.
ESA said Kasei Valles has likely seen floods of many different sizes, brought on by the changing tectonic and volcanic activity in the nearby Tharsis region over three billion years ago. The landscape was yanked apart under the strain of these forces, making groundwater create not only violent floods, but also fracture patterns seen at Sacra Mensa and Sacra Fossae.
According to the space agency, snow and ice melted by volcanic eruptions also contributed to torrential, muddy outpourings, while glacial activity may have further shaped the channel system.
"Now silent, one can only imagine from examples on Earth the roar of gushing water that once cascaded through Kasei Valles, undermining cliff faces and engulfing craters, and eventually flooding onto the plains of Chryse Planitia," ESA concluded.