[4] Mare Acidalium (Acidalian Sea) is the name of a telescopic albedo feature located at 45° N and 330° E on Mars.

[6] The quadrangle contains many interesting features, including gullies and possible shorelines of an ancient northern ocean.

When Mars Global Surveyor examined it with high resolution, the face turned out to just be an eroded mesa.

Although many ideas have been put forward to explain them, the most popular involve liquid water either coming from an aquifer or left over from old glaciers.

Various measurements and calculations show that liquid water could exist in an aquifer at the usual depths where the gullies begin.

[10] One variation of this model is that rising hot magma could have melted ice in the ground and caused water to flow in aquifers.

[11] On the other hand, there is evidence for the alternative theory because much of the surface of Mars is covered by a thick smooth mantle that is thought to be a mixture of ice and dust.

This ice-rich mantle, a few yards thick, smooths the land, but in places it has a bumpy texture, resembling the surface of a basketball.

During certain climate periods water vapor leaves polar ice and enters the atmosphere.

The water comes back to ground at lower latitudes as deposits of frost or snow mixed generously with dust.

Places on Mars that display polygonal ground may indicate where future colonists can find water ice.

Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed unto the surface.

Large areas of Mare Acidalium display bright spots on a dark background.

Mud volcanism here may be highly significant because long lived conduits for upwelling groundwater could have been produced.

There study using HiRISE images and CRISM data support the idea that these features are indeed mud volcanoes.

It is carved into the highlands of Idaeus Fossae, and it originated from the melting of ice in the ground after asteroid impacts.

[36][37][38][39] Indeed, a study published in June 2017, calculated that the volume of water needed to carve all the channels on Mars was even larger than the proposed ocean that the planet may have had.

A large team of scientists described how some of the surface in Ismenius Lacus quadrangle was altered by two Tsunamis.

Calculations show that the average height of the waves would have been 50 m, but the heights would vary from 10 m to 120 m. Numerical simulations show that in this particular part of the ocean two impact craters of the size of 30 km in diameter would form every 30 million years.

The parts of Mars studied in this research are Chryse Planitia and northwestern Arabia Terra.

An analogous process creates similar sized mounds in arctic tundra on Earth that are known as pingos, an Inuit word.

Martian ground water probably moved hundreds of kilometers, and in the process it dissolved many minerals from the rock it passed through.