Deep ocean currents are driven by density and temperature gradients. Thermohaline circulation is also known as the ocean's conveyor belt (which refers to deep ocean density driven ocean basin currents). These currents, called submarine rivers, flow under the surface of the ocean and are hidden from immediate detection.
The light-colored material is in areas of the Moon called the highlands, which represent the earliest crust on the Moon. Impact cratering shattered this crust and often deformed it, pushing some of it into mountain-high impact crater rims or ejecting it across the surface of the Moon.
The Atacama Desert is commonly known as the driest non-polar place in the world, especially the surroundings of the abandoned Yungay town (in Antofagasta Region, Chile).eological research suggests that in some sections of the Atacama Desert, such as in today's Chile, hyperaridity has persisted for the last 200 million years (since the Triassic). This desert is so arid, many mountains higher than 6,000 m (20,000 ft) are completely free of glaciers.