Science Graphic of the Week: Mapping Mars’ Missing Ice | WIRED
▻http://www.wired.com/2014/09/science-graphic-mars-water-map
Mars has oceans worth of ice. Most of it is concentrated at the poles, but there is also a substantial amount frozen in two bands of dusty soil that span the planet’s midlatitudes. The map above shows the gullies that form when some of that ice melts. A recent study used these gullies to estimate roughly how much ice is frozen in Mars’ soil.
The bands of soil—called the latitude-dependent mantle—cover less than a quarter of Mars’ surface, from about the 30th to the 60th lines of latitude on either side of the equator. Scientists believe the frozen soil was deposited by massive glaciers or something similar less than a million years ago. It is discontinuous, having melted away in some places and accumulated in others. It averages about 18-36 feet deep, but shielded from the sun on the pole-facing walls of craters, these deposits can be over 90 feet deep.
