Mars

Evidence of Frozen Water

Ice Patches

On July 28, 2005, the European Space Agency announced the existence of a crater partially filled with frozen water; some then interpreted the discovery as an "ice lake". Images of the crater, taken by the High Resolution Stereo Camera on board the European Space Agency's Mars Express spacecraft, clearly show a broad sheet of ice in the bottom of an unnamed crater located on Vastitas Borealis, a broad plain that covers much of Mars' far northern latitudes, at approximately 70.5° North and 103° East. The crater is 35 km wide and about 2 km deep.

The height difference between the crater floor and the surface of the water ice is about 200 metres. ESA scientists have attributed most of this height difference to sand dunes beneath the water ice, which are partially visible. While scientists do not refer to the patch as a "lake", the water ice patch is remarkable for its size and for being present throughout the year. Deposits of water ice and layers of frost have been found in many different locations on the planet.

Equatorial Frozen Sea

Surface features consistent with pack ice have been discovered in the southern Elysium Planitia. What appear to be plates of broken ice, ranging in size from 30 m to 30 km, are found in channels leading to a flooded area of approximately the same depth and width as the North Sea. The plates show signs of break up and rotation that clearly distinguish them from lava plates elsewhere on the surface of Mars. The source for the flood is thought to be the nearby geological fault Cerberus Fossae which spewed water as well as lava aged some 2 to 10 million years.[85] Not all scientists agree with these conclusions.

Glaciers

Glaciers formed much of the observable surface in large area of Mars. Much of the area in high latitudes, especially the Ismenius Lacus quadrangle, is believed to still contain enormous amounts of water ice. Recent evidence has led many planetary scientists to believe that water ice still exists as glaciers with a thin covering of insulating rock.Fretted terrain, many volcanoes, even some craters are believed to have many glaciers. Ridges of debris on the surface of the glaciers show the direction of ice movement. The surface of some glaciers has a rough texture due to sublimation of buried ice. The ice goes directly into a gas (this process is called sublimation) and leaves behind an empty space. Overlying material then collapses into the void.Glaciers are not pure ice; they contain dirt and rocks. At times, they will dump their load of materials into ridges. Such ridges are called moraines. Some places on Mars have groups of ridges that are twisted around; this may have been due to more movement after the ridges were put into place. Sometimes chunks of ice fall from the glacier and get buried in the land surface. When they melt and more or less round hole remains. On Earth we call these features kettles or kettle holes. Mendon Ponds Park in upstate NY has preserved several of these kettles. The picture from HiRISE below shows possible kettles in Moreux Crater.

Other pictures below show various features that appear to be connected with the existance of glaciers.

Moreux Crater moraines and kettle holes, as seen by HIRISE. Location is Ismenius Lacus quadrangle.

Clanis and Hypsas Valles, as seen by HiRISE. Ridges are probably due to glacial flow. So water ice is under a thin layer of rocks. Location is Ismenius Lacus quadrangle.

Gullies and possible remains of old glaciers in a crater in Eridania quadrangle, north of the large crater Kepler. One suspected glacier, to the right, has the shape of a tongue. Image taken with Mars Global Surveyor.

Tributary Glacier, as seen by HiRISE. Location is Ismenius Lacus quadrangle.

Coloe Fossae Lineated Valley Fill, as seen by HiRISE. Scale bar is 500 meters long. Location is Ismenius Lacus quadrangle.

Tongue-Shaped Glacier, as seen by Mars Global Surveyor. Location is Hellas quadrangle.

Polar Ice Caps

The Mars Global Surveyor acquired this image of the Martian north polar ice cap in early northern summer.

Both the the northern polar cap (Planum Boreum) and the southern polar cap (Planum Australe) are believed to grow in thickness during the winter and partially sublime during the summer. Data obtained by the Mars Express satellite, made it possible in 2004 to confirm that the southern polar cap has an average of 3 kilometres (1.9 mi) thick slab of CO2 ice[89] with varying contents of frozen water, depending on its latitude; the polar cap is a mixture of 85% CO2 ice and 15% water ice.[90] The second part comprises steep slopes known as 'scarps', made almost entirely of water ice, that fall away from the polar cap to the surrounding plains.[90] The third part encompasses the vast permafrost fields that stretch for tens of kilometres away from the scarps. NASA scientists calculate that the volume of water ice in the south polar ice cap, if melted, would be sufficient to cover the entire planetary surface to a depth of 11 metres.

Results, published in 2009, of radar measurements of the North Polar ice cap determined that the volume of water ice in the cap is 821,000 cubic kilometers (197,000 cubic miles). That's equal to 30% of the Earth's Greenland ice sheet or enough to cover the surface of Mars to a depth of 5.6 meters (dividing this volume by the surface area of Mars is how this number is found). The radar instrument is onboard the Mars Reconnaissance Orbiter.

Ground Ice

For many years, various scientists have suggested that some Martian surfaces look like Periglacial regions on Earth. Sometimes it is said that these are regions of Permafrost. These observations suggest that frozen water lies right beneath the surface. A common feature in the higher latitudes, Patterned ground, can occur in a number of shapes, including stripes and polygons. On the Earth, these shapes are caused by the freezing and thawing of soil. There are other types of evidence for large amounts of frozen water under the surface of Mars, such as terrain softening which rounds sharp topographical features.

sahil nakul mathur