The Phaethontis quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Phaethontis quadrangle is also referred to as MC-24 (Mars Chart-24).
The name comes from Phaethon, the son of Helios.Blunck, J. 1982. Mars and its Satellites, Exposition Press. Smithtown, N.Y.
The Phaethontis quadrangle lies between 30° and 65° south latitude and 120° and 180° west longitude on Mars. This latitude range is where numerous gullies have been discovered. An old feature in this area, called Terra Sirenum lies in this quadrangle; Mars Reconnaissance Orbiter discovered iron/magnesium smectites there. Part of this quadrangle contains what is called the Electris deposits, a deposit that is thick. It is light-toned and appears to be weak because of few boulders. Among a group of large craters is Mariner Crater, first observed by the Mariner 4 spacecraft in the summer of 1965. It was named after that spacecraft. A low area in Terra Sirenum is believed to have once held a lake that eventually drained through Ma'adim Vallis. 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. Its message just appeared as a blank screen.
Electris deposits The Electris deposits are light-toned sediments on Mars and are 100–200 m thick. Research using HiRISE images lead scientists to believe that the deposit is an accumulation of loess that initially were produced from volcanic materials in Tharsis or other volcanic centers. A team of researchers led by Laura Kerber found that the Electris deposits could have been formed from ash from the volcanoes Apollinaris Mons, Arsia Mons, and possibly Pavonis Mons.
Martian gullies
The Phaethontis quadrangle is the location of many gullies that may be due to recent flowing water. Some are found in the Gorgonum Chaos and in many craters near the large craters Copernicus and Newton.U.S. department of the Interior U.S. Geological Survey, Topographic Map of the Eastern Region of Mars M 15M 0/270 2AT, 1991 Gullies occur on steep slopes, especially on the walls of craters. Gullies are believed to be relatively young because they have few, if any craters. Moreover, they lie on top of sand dunes which themselves are considered to be quite young. Usually, each gully has an alcove, channel, and apron. Some studies have found that gullies occur on slopes that face all directions, others have found that the greater number of gullies are found on poleward facing slopes, especially from 30–44° S.
Although many ideas have been put forward to explain them, the most popular involve liquid water coming from an aquifer, from melting at the base of old glaciers, or from the melting of ice in the ground when the climate was warmer.Forget, F. et al. 2006. Planet Mars Story of Another World. Praxis Publishing. Chichester, UK. Because of the good possibility that liquid water was involved with their formation and that they could be very young, scientists are excited. Maybe the gullies are where we should go to find life.
There is evidence for all three theories. Most of the gully alcove heads occur at the same level, just as one would expect of an aquifer. Various measurements and calculations show that liquid water could exist in aquifers at the usual depths where gullies begin. One variation of this model is that rising hot magma could have melted ice in the ground and caused water to flow in aquifers. Aquifers are layer that allow water to flow. They may consist of porous sandstone. The aquifer layer would be perched on top of another layer that prevents water from going down (in geological terms it would be called impermeable). Because water in an aquifer is prevented from going down, the only direction the trapped water can flow is horizontally. Eventually, water could flow out onto the surface when the aquifer reaches a break—like a crater wall. The resulting flow of water could erode the wall to create gullies. Aquifers are quite common on Earth. A good example is "Weeping Rock" in Zion National Park, Utah.Harris, A and E. Tuttle. 1990. Geology of National Parks. Kendall/Hunt Publishing Company. Dubuque, Iowa
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. 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. The mantle may be like a glacier and under certain conditions the ice that is mixed in the mantle could melt and flow down the slopes and make gullies.NBC News Because there are few craters on this mantle, the mantle is relatively young. An excellent view of this mantle is shown below in the picture of the Ptolemaeus Crater Rim, as seen by HiRISE. The ice-rich mantle may be the result of climate changes. Changes in Mars's orbit and tilt cause significant changes in the distribution of water ice from polar regions down to latitudes equivalent to Texas. 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. The atmosphere of Mars contains a great deal of fine dust particles. Water vapor will condense on the particles, then fall down to the ground due to the additional weight of the water coating. When Mars is at its greatest tilt or obliquity, up to two centimeters of ice could be removed from the summer ice cap and deposited at midlatitudes. This movement of water could last for several thousand years and create a snow layer of up to around ten meters thick. When ice at the top of the mantling layer goes back into the atmosphere, it leaves behind dust, which insulating the remaining ice. Measurements of altitudes and slopes of gullies support the idea that snowpacks or glaciers are associated with gullies. Steeper slopes have more shade which would preserve snow. Higher elevations have far fewer gullies because ice would tend to sublimate more in the thin air of the higher altitude.
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. 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. Small amounts of liquid water from melted ground ice could be enough.http://www.spaceref.com:16090/news/viewpr.html?pid=7124, Calculations show that a third of a mm of runoff can be produced each day for 50 days of each Martian year, even under current conditions.
Associated features of gullies
Sometimes other features appear near gullies. At the base of some gullies there may be depressions or curved ridges. These have been called "spatulate depressions." These depressions form after glacial ice disappears. Steep walls often develop glaciers during certain climates. When the climate changes, the ice in the glaciers sublimates in the thin Martian atmosphere. Sublimation is when a substance goes directly from a solid state to a gas state. Dry ice on Earth does this. So when the ice at the base of a steep wall sublimates, a depression results. Also, more ice from higher up will tend to flow downward. This flow will stretch the surface rocky debris thereby forming transverse crevasses. Such formations have been termed "washboard terrain" because they resemble the old fashioned washboards.jawin, E, J. Head, D. Marchant. 2018. Transient post-glacial processes on Mars: Geomorphologic evidence for a paraglacial period. Icarus: 309, 187-206 The parts of gullies and some associated features of gullies are shown below in a HiRISE images.
Tongue-shaped glaciers
Possible pingos
The radial and concentric cracks visible here are common when forces penetrate a brittle layer, such as a rock thrown through a glass window. These particular fractures were probably created by something emerging from below the brittle Martian surface. Ice may have accumulated under the surface in a lens shape; thus making these cracked mounds. Ice being less dense than rock, pushed upwards on the surface and generated these spider web-like patterns. A similar process creates similar sized mounds in arctic tundra on Earth. Such features are called "pingos", an Inuit word. Pingos would contain pure water ice; thus they could be sources of water for future colonists of Mars.
Concentric crater fill Concentric crater fill, like lobate debris aprons and lineated valley fill, is believed to be ice-rich.Levy, J. et al. 2009. Concentric crater fill in Utopia Planitia: History and interaction between glacial "brain terrain" and periglacial processes. Icarus: 202. 462-476. Based on accurate topography measures of height at different points in these craters and calculations of how deep the craters should be based on their diameters, it is thought that the craters are 80% filled with mostly ice.Garvin, J., S. Sakimoto, J. Frawley. 2003. Craters on Mars: Geometric properties from gridded MOLA topography. In: Sixth International Conference on Mars. July 20–25, 2003, Pasadena, California. Abstract 3277. That is, they hold hundreds of meters of material that probably consists of ice with a few tens of meters of surface debris.Garvin, J. et al. 2002. Global geometric properties of martian impact craters. Lunar Planet. Sci: 33. Abstract # 1255.NASA.gov The ice accumulated in the crater from snowfall in previous climates.Kreslavsky, M. and J. Head. 2006. Modification of impact craters in the northern planes of Mars: Implications for the Amazonian climate history. Meteorit. Planet. Sci.: 41. 1633-1646Madeleine, J. et al. 2007. Exploring the northern mid-latitude glaciation with a general circulation model. In: Seventh International Conference on Mars. Abstract 3096. Recent modeling suggests that concentric crater fill develops over many cycles in which snow is deposited, then moves into the crater. Once inside the crater shade and dust preserve the snow. The snow changes to ice. The many concentric lines are created by the many cycles of snow accumulation. Generally snow accumulates whenever the axial tilt reaches 35 degrees.Fastook, J., J.Head. 2014. Concentric crater fill: Rates of glacial accumulation, infilling and deglaciation in the Amazonian and Noachian of Mars. 45th Lunar and Planetary Science Conference (2014) 1227.pdf
Magnetic stripes and plate tectonics