Exploratour - Carbon Cycle of Mars
Where did all the Carbon go?
Scientists say that although there is a lot of carbon in the atmosphere, there should be a whole lot more! Is it trapped in the rocks? Is it in the river channels? No one knows for sure.
These river valleys are similar to river valleys of Earth, but different in many ways too. The tributaries can be very short, on the order of 1 km in length. Compare this to river tributaries which can be hundreds of kilometers in length on Earth.