Standing on the floor of a sea that may have vanished 3 billion years ago.
Vastitas Borealis West is the western sector of the enormous lowland that rings Mars's north pole. It sits several kilometers below the planet's mean elevation and is a leading candidate for the floor of a hypothetical ancient ocean, sometimes called Oceanus Borealis.
Claim your plot here →The western reach of Vastitas Borealis is a smooth, low expanse blanketed by the Vastitas Borealis Formation — a layer of sediment and ice thought to be reworked material carried down from the highlands by catastrophic floods. Its low elevation and gentle slopes are exactly what would be expected if a large body of water once pooled across the northern hemisphere.
This half of the lowlands lies opposite the great outflow channels, so it may have received sediment ferried across the ancient basin. Whatever water existed is long gone from the surface, but researchers believe ground ice persists just meters down, making the region a scientific and future-resource target.
Like Earth's abyssal plains, Vastitas Borealis is a vast, flat, low-lying basin — but any sea that filled it dried out billions of years ago.