Rejoining Flows (Released 28 April 2005)

Originating on the margin of Lunae Planum, the Kasei Valliscomplex contains two main channels that run east-westacross Tempe Terra and empty into Chryse Planitia.<p>The formation of Kasei Vallis is still being studied and several theories exist. It is thought that volcanic subsurfaceing heating in the Tharsis/Lunae Planum region resulted in a release of water, which carved the channels and produced the landforms seen within the channels. One theory is that this was a one-time catastropic event, another theory speculates that several flooding events occurred over a long time period. Others have proposedthat some of the landforms (especially scour marks and teardrop shaped "islands") are the result of glacial flow rather than liquid flow. Teardrop shaped islands are common in terrestrial rivers, where the water is eroding material in the channel. A glacial feature called a <a href=&quot;http://www.zephryus.demon.co.uk/geography/resources/glaciers/drum.html&quot;>drumlin</a> has the exact same shape, but is formed by deposition beneath continental glaciers.<p>This two-image mosaic shows a region of the main channel where flows are rejoining at the tail of a large teardrop shapped island (center of image).