The Arabia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Arabia quadrangle is also referred to as MC-12 (Mars Chart-12).Davies, M.E.; Batson, R.M.; Wu, S.S.C. "Geodesy and Cartography" in Kieffer, H.H.; Jakosky, B.M.; Snyder, C.W.; Matthews, M.S., Eds. Mars. University of Arizona Press: Tucson, 1992.
The quadrangle contains part of the classic area of Mars known as Arabia. It also contains a part of Terra Sabaea and a small part of Meridiani Planum. It lies on the boundary between the young northern plains and the old southern highlands. The quadrangle covers the area from 315° to 360° west longitude and 0° to 30° north latitude.
Description The surface of the Arabia quadrangle appears to be very old because it has a high density of craters, but it is not near as high in elevation as typical old surfaces. On Mars the oldest areas contain the most craters; the oldest period is called Noachian after the quadrangle Noachis. The Arabia area contains many buttes and ridges. Some believe that during certain climate changes an ice-dust layer was deposited; later, parts were eroded to form buttes. Some outflow channels are found in Arabia, namely Naktong Vallis, Locras Valles, Indus Vallis, Scamander Vallis, and Cusus Valles.U.S. Department of the Interior U.S. Geological Survey, Topographic Map of the Eastern Region of Mars M 15M 0/270 2AT, 1991
This area is one of the dustest on the planet. Dust is often 20 meters deep with some places covered with 250 meters of dust.Morden, S. 2022. The Red Planet. Pegasus Books. New York.
Layers
Many places in Arabia are shaped into layers.Grotzinger, J. and R. Milliken (eds.) 2012. Sedimentary Geology of Mars. SEPM The layers can be a few meters thick or tens of meters thick. Recent research on these layers by scientists at California Institute of Technology (Caltech) suggest that ancient climate change on Mars caused by regular variation in the planet's tilt, or obliquity may have caused the patterns in the layers. On Earth, similar changes (astronomical forcing) of climate results in ice-age cycles.
A recent study of layers in craters in western Arabia revealed much about the history of the layers. Although the craters in this study are just outside the boundary for the Arabia quadrangle the findings would probably apply to the Arabia quadrangle as well. The thickness of each layer may average less than 4 meters in one crater, but 20 meters in another. The pattern of layers measured in Becquerel crater, suggests that each layer was formed over a period of about 100,000 years. Moreover, every 10 layers were bundled together into larger units. The 10-layer pattern is repeated at least 10 times. So every 10-layer pattern took one-million years to form.
The tilt of the Earth's axis changes by only a little more than 2 degrees; it is stabilized by the relatively large mass of the Moon. In contrast Mars's tilt varies by tens of degrees. When the tilt (or obliquity) is low, the poles are the coldest places on the planet, while the equator is the warmest—as on Earth. This causes gases in the atmosphere, like water and carbon dioxide, to migrate pole ward, where they freeze. When the obliquity is higher, the poles receive more sunlight, causing those materials to migrate away. When carbon dioxide moves from the poles, the atmospheric pressure increases, maybe causing a difference in the ability of winds to transport and deposit sand. Also, with more water in the atmosphere sand grains may stick and cement together to form layers. This study of the thickness of layers was done using stereo topographic maps obtained by processing data from the high-resolution camera onboard NASA's Mars Reconnaissance Orbiter.
Recent research leads scientists to believe that some of the craters in Arabia may have held huge lakes. Cassini Crater and Tikonravov Crater probably once were full of water since their rims seem to have been breached by water. Both inflow and outflow channels have been observed on their rims. Each of these lakes would have contained more water than Earth's Lake Baikal, our largest freshwater lake by volume. The watersheds for lakes in Arabia seem to be too small to gather enough water by precipitation alone; therefore it is thought that much of their water came from groundwater.Fassett, C. and J. Head III. 2008. Valley network-fed, open-basin lakes on Mars: Distribution and implications for Noachian surface and subsurface hydrology. Icarus: 198. 39–56.
Another group of researchers proposed groundwater with dissolved minerals came to the surface, in and later around craters, and helped to form layers by adding minerals (especially sulfate) and cementing sediments. Upon close examination, Arabia layers appear to have a slight tilt. This tilt supports formation with the action of a rising water table. A water table generally follows the topography. Since the layers slope slightly down toward the northwest, the layers may have been created by groundwater, rather than a single large sea that has been suggested.
This hypothesis is supported by a groundwater model and by sulfates discovered in a wide area. At first, by examining surface materials with the Opportunity rover, scientists discovered that groundwater had repeatedly risen and deposited sulfates. Later studies with instruments on board the Mars Reconnaissance Orbiter showed that the same kinds of materials exist in a large area that included Arabia.M. Wiseman, J. C. Andrews-Hanna, R. E. Arvidson3, J. F. Mustard, K. J. Zabrusky DISTRIBUTION OF HYDRATED SULFATES ACROSS ARABIA TERRA USING CRISM DATA: IMPLICATIONS FOR MARTIAN HYDROLOGY. 42nd Lunar and Planetary Science Conference (2011) 2133.pdf
Light-toned materials Certain areas of Mars show ground that has a much lighter-tone than most other areas. Much of the surface of Mars is dark because of extensive flows of the dark lava rock basalt. Studies with spectroscopes from orbit have shown that many light-toned areas contain hydrated minerals, and/or clay minerals.Weitz, C. et al. 2017. LIGHT-TONED MATERIALS OF MELAS CHASMA: EVIDENCE FOR THEIR FORMATION ON MARS. Lunar and Planetary Science XLVIII (2017) 2794.pdf That means that water was once there in order to produce these substances. In short, light-toned materials are markers for the past presence of water.
Craters
Impact craters generally have a rim with ejecta around them, in contrast volcanic craters usually do not have a rim or ejecta deposits. As craters get larger (greater than 10 km in diameter) they usually have a central peak. The peak is caused by a rebound of the crater floor following the impact. Sometimes craters display layers. Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed unto the surface. Hence, craters can show us what lies deep under the surface.
Some craters in Arabia are classified as pedestal craters. A pedestal crater is a crater with its ejecta sitting above the surrounding terrain and thereby forming a raised platform. They form when an impact crater ejects material which forms an erosion resistant layer, thus protecting the immediate area from erosion. As a result of this hard covering, the crater and its ejecta become elevated, as erosion removes the softer material beyond the ejecta.http://hirise.lpl.eduPSP_008508_1870 Some pedestals have been accurately measured to be hundreds of meters above the surrounding area. This means that hundreds of meters of material were eroded away. Pedestal craters were first observed during the Mariner missions.Bleacher, J. and S. Sakimoto. Pedestal Craters, A Tool For Interpreting Geological Histories and Estimating Erosion Rates. LPSC
Researchers believe over 200 new craters are formed each year on Mars, based on study of years of HiRISE images.
Possible methane One study with the Planetary Fourier Spectrometer in the Mars Express spacecraft found possible methane in three areas of Mars, one of which was in Arabia. One possible source of methane is from the metabolism of living bacteria.Allen, C., D. Oehler, and E. Venechuk. Prospecting for Methane in Arabia Terra, Mars – First Results. Lunar and Planetary Science XXXVII (2006). 1193.pdf-1193.pdf. However, a recent study indicates that to match the observations of methane, there must be something that quickly destroys the gas, otherwise it would be spread all through the atmosphere instead of being concentrated in just a few locations. There may be something in the soil that oxidizes the gas before it has a chance to spread. If this is so, that same chemical would destroy organic compounds, thus life would be very difficult on Mars.
Deformation bands The Mars Reconnaissance Orbiter showed deformation bands in Capen Crater, located in the Arabia quadrangle. Deformation bands are small faults with very small displacements.DOI.org They often proceed large faults. They develop in porous rocks, like sandstone. They can restrict and/or change the flow of fluids like water and oil. They are common in the Colorado Plateau. Good examples form in the Entrada Sandstone in the San Rafael Swell in Utah.Schultz, R. 2009. Fractures and Deformation Bands in Rock: A Field Guide and Journey into Geologic Fracture Mechanics. Oxford University Press The bands represent failure by localized frictional sliding.Schultz, R. and R. Siddharthan. 2005. A general framework for the occurrence and faulting of deformation bands in porous granular rocks. Tectonophysics: 411. 1–18. The bands on Mars are a few meters wide and up to a few kilometers long. They are caused by the compression or stretching of underground layers. Erosion of overlying layers make them visible at the surface. Capen Crater was unnamed before the discovery of deformation bands. It was named for Charles Capen, who studied Mars at JPL's Table Mountain Observatory in California and at Lowell Observatory in Arizona.
Geological history Recent studies, reported in the journal Icarus, have suggested that the area underwent several phases in its formation:
A large basin, maybe from an impact, was produced early in Martian history. It was so early that Mars still had a magnetic field generated by movements in a liquid core. Present day Arabia possesses a remnant magnetism from that ancient era. Sediments flowed into the basin. Water entered the basin. Because Tharsis, on the other side of Mars, became so massive, the area around Arabia was pushed out. As it bulged upward, there was increased erosion which exposed old layers. When portions of a planet that can be subject to erosion rise, there is greatly increased erosion; Earth's Grand Canyon became very deep because it was eroded into a high plateau. Over the following 4 billion years, the area was modified by various geological processes. Central peaks and ejecta shapes indicate that parts of Arabia are still water enriched.Hartmann, W. 2003. A Traveler's Guide to Mars. Workman Publishing. NY NY.Dohm, J. et al. 2007. Possible ancient giant basin and related water enrichment in the Arabia Terra province, Mars. Icarus: 190. 74–92.Edgett, K. and M. Malin. 2002. Martian sedimentary rock stratigraphy: Outcrops and interbedded craters of northwest Sinus Meridiani and southwest Arabia Terra. Geophysical Research Letters: 29. 32.
Dark slope streaks