The Thaumasia Region
MC-25
The Thaumasia Region covers the area from 60° to 120° west longitude and 30° to 65° south latitude on Mars. One of the first major networks of stream channels, called Warrego Valles, were discovered here by early orbiters. Another sign of water is the presence of gullies carved into steep slopes. The highest elevations are red and the lowest are blue.
Topographical Map of the Thaumasia Region
Although many ideas have been put forward to explaining Martian gullies, 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. 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.
Image of Thaumasia Region
The northern part of this Region includes Thaumasia plateau. The southern part contains heavily cratered highland terrain and relatively smooth, low plains. The east-central part includes Lowell Crater.
As usual we begin our survey from the northeast corner of the Region. We first encounter the Icaria Planum in the northeast area of the Region bordered on the east by the Claritas Rupes and the Claritas Fossae further south.
The Icaria Planum is a region on Mars in the Thaumasia Region of Mars that is 566.59 km across and is located at 43.27 S and 253.96°E.
Topographical Map of Icaria Planum
Layers in mantle deposit in Icaria Planum, as seen by HiRISE, under the HiWish program. Mantle was probably formed from snow and dust falling during a different climate.
Crater and one of many nearby channels, as seen by HiRISE under HiWish program. Picture is from Icaria Planum.
At 248°E 43.4°S we come across some strange terrain in the Icaria Planum that is worth noting:
Strange surface features, as seen by HiRISE under the HiWish program
Near the northern border of the Thaumasia Region from 251°E to 35°S is the Claritas Rupes.
Striated Highlands Near Claritas Rupes
This observation shows striated highlands that are probably the result of what is termed "mass wasting" when material higher up collapses and flows down slope. This area was also imaged by MOC, but HiRISE resolution (which has a smaller footprint) can show greater detail, enabling us to look for objects such as boulders. Claritas Rupes extends southward from the western edge of Noctis Labyrinthus and divides the volcanic flows of Deadalia Planum and Solis Planum. This area also has other interesting geological features, such as fractures and a graben, which is a depressed block of land bordered by parallel faults.
To the south of Claritas Rupes we come to Claritas Fossae. Note only the western part of these two areas can be considered a part of the Icaria Planum from about 265°E westward extending as far south as about 45°S.
Claritas Fossae Graben at 261°E 36.5°S
Trough in Claritas Fossae at 254°E 38°S.
Just as on Earth, volcanism and tectonics are found together on Mars. Here is an example: the ridges and fractures of Claritas Fossae are affecting or perhaps hosting the volcanic flows of Solis Planum. Claritas Fossae is a group of troughs in the Phoenicis Lacus and Thaumasia Regions of Mars, located at 31.5° S and 254°E. The structure is 2,050 km long (from north to south) and was named after a classical albedo feature.
Claritas Fossae as seen by HiRISE. Note the steep scarp which is located at 31.5°S 254°E
Long narrow depressions on Mars are called fossae. This term is derived from Latin; therefore fossa is singular and fossae is plural. Troughs form when the crust is stretched until it breaks. The stretching can be due to the large weight of a nearby volcano. Fossae/pit craters are common near volcanoes in the Tharsis and Elysium regions. A trough often has two breaks with a middle section moving down, leaving steep cliffs along the sides; such a trough is called a graben.
To the southwest of the Icaria Planum in the Aonia Terra we come to Porter Crater at 246°E 50.5°S.
Porter Crater Rim, as seen by MGS. Location is 49.51 degrees south latitude and 246 degrees east longitude
Porter Crater: is a large-scale impact crater in the Thaumasia Region on the planet Mars, situated in Aonia Terra at 50.5° south and 246º east. The impact caused a bowl 105 kilometers (65 mi) across. The name was chosen in 1973 by the International Astronomical Union in honor of the US astronomer and explorer, Russell W. Porter (1871-1949).
All of the Aonia Terra Region follows the 50°S line across the Thaumasia Region. I will post a image of Aonia Terra each time we cross the 50°S line since it crosses the entire Region close to that latitude.
Topographical Map of Aonia Terra at 255.6°E 53.6°S
The Aonia Terra Covers an expanse of over 4,000 kilometers.
The next feature of interest we come to is Brashear Crater centered at 241°E 54°S right on the western border of the Thaumasia Region.
Topographical Map of Brashear Crater
Crater floor covered with sand dunes in the shape of cells, as seen by HiRISE under HiWish program.
Many places on Mars have sand dunes. Some craters in Thaumasia Region show dark blotches in them. High resolution photos show that the dark markings are dark sand dunes. Dark sand dunes probably contain the igneous rock basalt. Brashear Crater, is one such crater with dark dunes.
Dark Dunes in Brashear Crater
Brashear Crater is 79 kilometers in diameter and is named after Dr. John Alfred Brashear (November 24, 1840 – April 8, 1920) who was an American astronomer and instrument builder.
The next feature of interest we come to is Ross Crater centered at 253°E 53°S.
CTX context for gullies in Ross crater.
Enlargement of part of previous image showing smaller gullies inside larger ones. Water probably flowed in these gullies more than once.
Another 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. 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. Ross Crater is 82.51 km in diameter. It was named after Frank E. Ross, an American astronomer (1874-1966). The crater's name was approved in 1973.
The Climate of Mars
Sample of the Weather on Mars
The climate of Mars has been an issue of scientific curiosity for centuries, not least because Mars is the only terrestrial planet whose surface can be directly observed in detail from the Earth with help from a telescope. Although Mars is smaller at 11% of Earth's mass and 50% farther from the Sun than the Earth, its climate has important similarities, such as the polar ice caps, seasonal changes and the observable presence of weather patterns. It has attracted sustained study from planetologists and climatologists. Although Mars's climate has similarities to Earth's, including seasons and periodic ice ages, there are also important differences such as the absence of liquid water (though frozen water exists) and much lower thermal inertia. Mars' atmosphere has a scale height of approximately 11 km (36,000 ft), 60% greater than that on Earth. The climate is of considerable relevance to the question of whether life is or was present on the planet.
Mars has been studied by Earth-based instruments since as early as the 17th century but it is only since the exploration of Mars began in the mid-1960s that close-range observation has been possible. Flyby and orbital spacecraft have provided data from above, while direct measurements of atmospheric conditions have been provided by a number of landers and rovers. Advanced Earth orbital instruments today continue to provide some useful "big picture" observations of relatively large weather phenomena. This observational work has been complemented by a type of scientific computer simulation called the Mars General Circulation Model.
Mars General Circulation Model
The Mars general circulation model (MGCM) is the result of a research project by NASA to understand the nature of the general circulation of the atmosphere of Mars, how that circulation is driven and how it affects the climate of Mars in the long term. This Mars climate model is a complex 3-dimensional (height, latitude, longitude) model, which represents the processes of atmospheric heating by gases and ground-air heat transfer, as well as large-scale atmospheric motion. Several different iterations of MGCM have led to an increased understanding of Mars as well as the limits of such models. Models are limited in their ability to represent atmospheric physics that occurs at a smaller scale than their resolution. They also may be based on inaccurate or unrealistic assumptions about how Mars works and certainly suffer from the quality and limited density in time and space of climate data from Mars.
Clouds:
Mars' temperature and circulation vary from year to year (as expected for any planet with an atmosphere). Mars lacks oceans, a source of much inter-annual variation. Mars Orbiter Camera data beginning in March 1999 and covering 2.5 Martian years show that Martian weather tends to be more repeatable and hence more predictable than that of Earth. If an event occurs at a particular time of year in one year, the available data (sparse as it is) indicate that it is fairly likely to repeat the next year at nearly the same location give or take a week. On September 29, 2008, the Phoenix lander took pictures of snow falling from clouds 4.5 km above its landing site near Heimdall crater. The precipitation vaporized before reaching the ground, a phenomenon called virga. In meteorology, virga is an observable streak or shaft of precipitation that falls from a cloud but evaporates or sublimes before reaching the ground.
Animation of ice clouds moving above the Phoenix landing site over a period of ten minutes (August 29, 2008).
Animation of ice clouds moving above the Phoenix landing site over a period of ten minutes (August 29, 2008). Mars' dust storms can kick up fine particles in the atmosphere around which clouds can form. These clouds can form very high up, up to 100 km (62 mi) above the planet. The clouds are very faint and can only be seen reflecting sunlight against the darkness of the night sky. In that respect, they look similar to the mesospheric clouds, also known as noctilucent clouds on Earth, which occur about 80 km (50 mi) above our planet.
Temperature:
Differing values have been reported for the average temperature on Mars, with a common value being -55 °C (-67 °F). Surface temperatures may reach a high of about 20 °C (68 °F) at noon, at the equator, and a low of about -153 °C (-243 °F) at the poles. Actual temperature measurements at the Viking landers' site range from -17.2 °C (1.0 °F) to -107 °C (-161 °F). The warmest soil temperature on the Mars surface estimated by the Viking Orbiter was 27 °C (81 °F). The Spirit rover recorded a maximum daytime air temperatures in the shade of 35 °C (95 °F), and regularly recorded temperatures well above 0 °C (32 °F), except in winter.
Wind:
The surface of Mars has a very low thermal inertia, which means it heats quickly when the sun shines on it. Typical daily temperature swings, away from the polar regions, are around 100 K. On Earth, winds often develop in areas where thermal inertia changes suddenly, such as from sea to land. There are no seas on Mars, but there are areas where the thermal inertia of the soil changes, leading to morning and evening winds akin to the sea breezes on Earth. At low latitudes the Hadley circulation dominates, and is essentially the same as the process which on Earth generates the trade winds. At higher latitudes a series of high and low pressure areas, called baroclinic pressure waves, dominate the weather. Mars is dryer and colder than Earth, and in consequence dust raised by these winds tends to remain in the atmosphere longer than on Earth as there is no precipitation to wash it out (excepting CO2 snowfall).
Effect of Dust Storms:
When the Mariner 9 probe arrived at Mars in 1971, the world expected to see crisp new pictures of surface detail. Instead they saw a near planet-wide dust storm with only the giant volcano Olympus Mons showing above the haze. The storm lasted for a month, an occurrence scientists have since learned is quite common on Mars. As observed by the Viking spacecraft from the surface, "during a global dust storm the diurnal temperature range narrowed sharply, from fifty degrees to only about ten degrees, and the wind speeds picked up considerably---indeed, within only an hour of the storm's arrival they had increased to 17 m/s (38 mph), with gusts up to 26 m/s (58 mph). Nevertheless, no actual transport of material was observed at either site, only a gradual brightening and loss of contrast of the surface material as dust settled onto it. On June 26, 2001, the Hubble Space Telescope spotted a dust storm brewing in Hellas Basin on Mars (below). A day later the storm "exploded" and became a global event. Orbital measurements showed that this dust storm reduced the average temperature of the surface and raised the temperature of the atmosphere of Mars by 30 °C. The low density of the Martian atmosphere means that winds of 18 to 22 m/s (40 to 49 mph) are needed to lift dust from the surface, but since Mars is so dry, the dust can stay in the atmosphere far longer than on Earth, where it is soon washed out by rain.
2001 Hellas Basin dust storm
Seasons:
Mars has an axial tilt of 25.2°. This means that there are seasons on Mars, just as on Earth. The eccentricity of Mars' orbit is 0.1, much greater than the Earth's present orbital eccentricity of about 0.02. The large eccentricity causes the isolation on Mars to vary as the planet orbits the Sun (the Martian year lasts 687 days, roughly 2 Earth years). As on Earth, Mars' obliquity dominates the seasons but, because of the large eccentricity, winters in the southern hemisphere are long and cold while those in the North are short and warm. It is now widely believed that ice accumulated when Mars' orbital tilt was very different from what it is now (the axis the planet spins on has considerable "wobble," meaning its angle changes over time). A few million years ago, the tilt of the axis of Mars was 45 degrees instead of its present 25 degrees. Its tilt, also called obliquity, varies greatly because its two tiny moons cannot stabilize it like our moon. Many features on Mars, especially in the Ismenius Lacus Region, are believed to contain large amounts of ice. The most popular model for the origin of the ice is climate change from large changes in the tilt of the planet's rotational axis. At times the tilt has even been greater than 80 degrees. Large changes in the tilt explains many ice-rich features on Mars
In spring, sublimation of ice causes sand from below the ice layer to form fan-shaped deposits on top of the seasonal ice.
Season Sols (on Mars) Days (on Earth)
Northern Spring, Southern Autumn: 193.30 92.764
Northern Summer, Southern Winter: 178.64 93.647
Northern Autumn, Southern Spring: 142.70 89.836
Northern Winter, Southern Summer: 153.95 88.997
Climate zones:
Terrestrial Climate zones first have been defined by Wladimir Köppen based on the distribution of vegetation groups. Climate classification is furthermore based on temperature, rainfall, and subdivided based upon differences in the seasonal distribution of temperature and precipitation; and a separate group exists for extra zonal climates like in high altitudes. Mars has neither vegetation nor rainfall, so any climate classification could be only based upon temperature; a further refinement of the system may be based on dust distribution, water vapor content, occurrence of snow. Solar Climate Zones can also be easily defined for Mars.
Mars Global Climate Zones, based on temperature, modified by topography, albedo, actual solar radiation.
Summary:
Mars Global Climate Zones, based on temperature, modified by topography, albedo, actual solar radiation. A=Glacial (permanent ice cap); B=Polar (covered by frost during the winter which sublimates during the summer); C=North (mild) Transitional (Ca) and C South (extreme) Transitional (Cb); D= Tropical; E= Low albedo tropical; F= Subpolar Lowland (Basins); G=Tropical Lowland (Chasmata); H=Subtropical Highland (Mountain).
Northeast of Ross crater is Coblentz Crater centered at 270°E 55°S.
Coblentz Crater
Coblentz Crater is 112 kilometers in diameter and was named after William Weber Coblentz (November 20, 1873 – September 15, 1962) who was an American physicist notable for his contributions to infrared radiometry and spectroscopy.
Next we cross another part of the Aonia Terra Area around 50°S.
Aonia Terra Sample from about 270-290°E
These dunes in Aonia Terra are being monitored for changes such as gullies, which form over the winter from the action of carbon dioxide frost. The season in which these images were acquired in late fall in the Southern hemisphere. Frost is just starting to accumulate here, and is concentrated on pole-facing slopes and in the troughs between the meter-scale ripples. The colors have been enhanced in the sub-image. Throughout the latter part of this video in Aonia Terra, it is possible to make out regular polygonal shaped patterns. Here on Earth, wherever ice-rich permafrost occurs (soil which stays frozen throughout the year), the ground may crack and form similar patterns to those we see on Mars. Despite remaining below freezing, changes in seasons and ground temperature cause significant thermal-contraction stress, enough so that the terrain fractures change into a honeycomb network of subsurface cracks. Criss-crossed dark paths wind throughout this region. Dust devils, turbulent whirlwinds fueled by rising ground-warmed atmosphere, track across the surface, stripping the ground of bright surface dust as they go. Comparable to miniature tornadoes, they efficiently transport surface materials on Mars. Left in their passing is the darker coarse-grained soil underneath.
To the northwest of Coblentz Crater is the Thaumasia Fossae located between 257-265°E and between 45-50°S.
Thaumasia Fossae Area at 261.8°E 47.3°S
The next area of interest we come to is the Warrego Valles located at about 296°E and 42°S.
Channels near Warrego Valles, as seen by THEMIS. These branched channels are strong evidence for flowing water on Mars, perhaps during a much warmer period.
Mariner 9 and Viking Orbiter images, showed a network of branching valleys in the Thaumasia Region called Warrego Valles. These networks are evidence that Mars may have once been warmer, wetter, and perhaps had precipitation in the form of rain or snow. A study with the Mars Orbiter Laser Altimeter, Thermal Emission Imaging System (THEMIS) and the Mars Orbiter Camera (MOC) support the idea that Warrego Valles was formed from precipitation and run off. At first glance they resemble river valleys on our Earth. But sharper images from more advanced cameras reveal that the valleys are not continuous. They are very old and may have suffered from the effects of erosion. The picture above shows some of these branching valleys
Warrego Valles
To the north of Warrego Valles on the border we com to Solis Planum which stretches from 265-280°E. Solis Planum is a high-elevation volcanic plain located south of Valles Marineris. This particular location is south of the southeastern tip of Noctis Labyrinthus. Solis Planum covers and area of 1700 kilometers.
Wrinkle Ridge in Solis Planum at 276°E 26°S
This observation shows a wrinkle ridge in the Solis Planum, a region of Mars that is a high-elevation volcanic plain located south of the Valles Marineris canyon system and east of the Tharsis volcanic complex. In the Solis Planum, wrinkle ridges are typically spaced apart roughly 40 kilometers (25 miles). Wrinkle ridges are linear to arcuate positive relief features and are often characterized by a broad arch topped with a crenulated ridge. These features have been identified on many bodies such as the Moon, Mercury, and Venus. On Mars, they are many tens-to- hundreds of kilometers long, tens of kilometers wide, and have a relief of a few hundred meters. Wrinkle ridges are most commonly believed to form from horizontal compression or shortening of the crust due to faulting and are often found in volcanic plains. Wrinkle ridges commonly have asymmetrical cross sectional profiles and an offset in elevation on either side of the ridge. The ridge in this image appears to have a steeper southeast facing slope and a more gentle northwest facing slope. Some layering is also apparent in the ridge. Large dunes border the ridge to the north. The reddish colors visible in the color image most likely indicate the presence of dust (or indurated dust).
The Solis Planum Area
To the east of Solis Planum is Voeykov Crater centered at 284°E 31.5°S.
Voeykov Crater in the Infrared
Voeykov Crater is 76 kilometers in diameter and is named after the Russian astronomer A.I. Voeykov.
Going to the southwest we come to the Coracis Fossae. The Coracis Fossae covers the southeast region of the uplift south of the Solis Planum. Roughly from 284°E to about 275°E and going as far south as 42°S. It covers a large area and has a diameter of 749 kilometers. It is named after an albedo feature.
Location of Coracis Fossae
Inclined view of Coracis Fossae
Coming down from the uplift that is Coracis Fossae we head to south to Slipher Crater which is centered at 275.5°E 47°S.
Slipher Crater
Slipher Crater is 127 kilometers in diameter and is named after Vesto Melvin Slipher (November 11, 1875 – November 8, 1969) who was an American astronomer.
Channels in Aonia Terra at 282°E 41°S.
Next we come to a Lowell Crater centered at 279°E 52.5°S.
Lowell Crater
Lowell crater is somewhat special in that it has a ring on the floor which gives it a sort of bull's eye appearance. It should be special because it was named after Percival Lowell who built the Lowell Observatory in Flagstaff Arizona in 1894. He used the observatory to discover over 500 canals on Mars. When pictures were received from spacecraft, the canals were found to be illusions. However, Lowell promoted the idea that they were constructed by an intelligent race. Much of the later interest in Mars exploration resulted from the efforts of Percival Lowell. Lowell Crater is 203 kilometers in diameter. It is considered to be a part of Aonia Terra.
Just to the southwest of there we come to a mountain called Aonia Mons located at 272.5°E 53.5°S.
Location of Aonia Mons
South of there we come to the Aonia Planum Area:
Aonia Planum Area
In the center of which is Aonis Tholus which is a small dome shaped mountain located at 280°E 59°S.
To the southeast of this Aonia Planum is a escarpment called Argyre Rupes starting at 294°E 64.5°S and going in a northwesterly direction to about 291°E 60°S.
Topographical Map of Argyre Rupes
Going almost directly north and east of Lowell Crater we come to Douglass Crater centered at 289.5°E 52°S.
Central Structure of Douglass Crater
Douglass Crater is 94 kilometers in diameter and is named after A. E. (Andrew Ellicott) Douglass (July 5, 1867, Windsor, Vermont – March 20, 1962, Tucson, Arizona) was an American astronomer. Douglass crater is part of Aonia Terra.
Continuing north we come to the next important feature we come to is Babakin Crater located at 289°E 37°S.
Bedrock in Babakin Crater
HiRISE acquires many images of bedrock exposures inside impact craters, because deep bedrock may be exposed in the central uplift, or new deposits may form on the floor. The sub image shows an enhanced-color section of the crater floor of one crater. There are layers of rock with different colors (from different minerals) exposed in places where the dark reddish wind-blown drifts have been removed. Babakin Crater is 78 kilometers in diameter and is named after Georgy Nikolayevich Babakin ( November 13, 1914 – August 3, 1971) who was a Soviet engineer working in the space program.
The final area of importance is the Bosphorus Planum area in the northeast corner of the Thaumasia Region.
Textured Mesa Southeast of Bosporus Planum
Also imaged by MRO's Context Camera, this observation shows one of two odd, rounded mesas with a knobby/pitted texture. This mesa may be the last remnants of a formerly more extensive geologic unit. Given the particular pitted texture, this formation could be ice-rich. High resolution images can greatly help to characterize the surface texture and allow us to compare other mid-latitude-type landforms, which may have some connection with ice and sublimation degradation processes.
Many Fantastically Colorful Gullies in a Fresh Impact Crater in the Bosporus Planum
