desert pavement

Soils under desert pavement have an unusually high concentration of nitrate, a type of salt, close to the surface.

Vulnerable to erosion by rain and wind if the desert pavement is disrupted, this vast source of nitrate could contaminate surface and groundwaters, posing an environmental risk.

Topics include: imaging of impact strata on Mars' Holden Crater; Eocene-Oligocene conditions leading to the freezing of Antarctica; evidence that liquid water is not responsible for recent changes observed in Martian gullies; new insights into Cretaceous early Albian greenhouse conditions and implications for future atmospheric carbon dioxide levels; new estimates of Earth's copper supply; discovery of large nitrate pools under the Mojave's desert pavement; frequency of magnitude 9 earthquakes; and the pre-Grand Canyon Colorado River.