An old feature in this area, called Terra Sirenum lies in this quadrangle; Mars Reconnaissance Orbiter discovered iron/magnesium smectites there.

[5][page needed] A low area in Terra Sirenum is believed to have once held a lake that eventually drained through Ma'adim Vallis.

[6][7][8][page needed] Russia's Mars 3 probe landed in the Phaethontis quadrangle at 44.9° S and 160.1° W in December 1971.

It landed at a speed of 75 km per hour, but survived to radio back 20 seconds of signal, then it went dead.

[19][20] Because of the good possibility that liquid water was involved with their formation and that they could be very young, scientists are excited.

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

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

[22] As for the next theory, much of the surface of Mars is covered by a thick smooth mantle that is thought to be a mixture of ice and dust.

[23][24][25] This ice-rich mantle, a few yards thick, smoothes the land, but in places it has a bumpy texture, resembling the surface of a basketball.

An excellent view of this mantle is shown below in the picture of the Ptolemaeus Crater Rim, as seen by HiRISE.

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.

This movement of water could last for several thousand years and create a snow layer of up to around 10 meters thick.

[33] The third theory might be possible since climate changes may be enough to simply allow ice in the ground to melt and thus form the gullies.

During a warmer climate, the first few meters of ground could thaw and produce a "debris flow" similar to those on the dry and cold Greenland east coast.

[34] Since the gullies occur on steep slopes only a small decrease of the shear strength of the soil particles is needed to begin the flow.

The radial and concentric cracks visible here are common when forces penetrate a brittle layer, such as a rock thrown through a glass window.

Ice being less dense than rock, pushed upwards on the surface and generated these spider web-like patterns.

Researchers believe these magnetic stripes on Mars are evidence for a short, early period of plate tectonic activity.

A magnetic field of a planet is believed to be caused by fluid motions under the surface.

This magnetism is lost only if the rock is subsequently heated above a particular temperature (the Curie point which is 770 °C for iron).

[59] Based on chloride deposits and hydrated phyllosilicates, Alfonso Davila and others believe there is an ancient lakebed in Terra Sirenum that had an area of 30,000 km2 (12,000 sq mi) and was 200 metres (660 ft) deep.

Other evidence that supports this lake are normal and inverted channels like ones found in the Atacama Desert.

[60] The Elysium quadrangle is home to large troughs (long narrow depressions) called fossae in the geographical language used for Mars.

[61] The density of impact craters is used to determine the surface ages of Mars and other solar system bodies.

Water from the melting ice dissolves minerals, and then deposits them in cracks or faults that were produced with the impact.

Primitive organisms may have developed in such lakes; hence, some craters may be prime targets for the search for evidence of life on the Red Planet.

Much of the Martian surface is covered with a thick ice-rich, mantle layer that has fallen from the sky a number of times in the past.

[92][93][94][95] 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.

[104] They have even blown the dust off of the solar panels of the two Rovers on Mars, thereby greatly extending their lives.