syrtis major


nicole: Clouds over Mars, photographed by Mars Global Surveyor, 2001.

13 pairs of images, taken through blue (left) and red (right) filters, 14th February-5th June 2001; Ls 117.0° to Ls 173.5°, the latter two thirds of the northern summer.

At the top of each gif is the north polar cap. The light area at the bottom is the northwest edge of the massive Hellas Planitia basin (the bright crater on its rim is Terby, 170km across). Left of centre are the Syrtis Major highlands; right of centre is the Isidis Planitia; you can definitely see clouds affected by the terrain’s change in altitude.

Image credit: NASA/JPL/MGS/MSSS. Animation: AgeOfDestruction.



Brown University researchers have published the most detailed geological history to date for a region of Mars known as Northeast Syrtis Major, a spot high on NASA’s list of potential landing sites for its next Mars rover to be launched in 2020.

The region is home to a striking mineral diversity, including deposits that indicate a variety of past environments that could have hosted life. Using the highest resolution images available from NASA’s Mars Reconnaissance Orbiter, the study maps the extent of those key mineral deposits across the surface and places them within the region’s larger geological context.

“When we look at this in high resolution, we can see complicated geomorphic patterns and a diversity of minerals at the surface that I think is unlike anything we’ve ever seen on Mars,” said Mike Bramble, a Ph.D. student at Brown who led the study, which is published in the journal Icarus. “Within a few kilometers, there’s a huge spectrum of things you can see and they change very quickly.”

If NASA ultimately decides to land at Northeast Syrtis, the work would help in providing a roadmap for the rover’s journey.

“This is a foundational paper for considering this part of the planet as a potential landing site for the Mars 2020 rover,” said Jack Mustard, a professor in Brown’s Department of Earth, Environmental and Planetary Sciences and a coauthor on the paper. “This represents an exceptional amount of work on Mike’s part, really going into the key morphologic and spectroscopic datasets we need in order to understand what this region can tell us about the history of Mars if we explore it with a rover.”

Past Habitable Environments

Northeast Syrtis sits between two giant Martian landforms – an impact crater 2,000 kilometers in diameter called the Isidis Basin, and a large volcano called Syrtis Major. The impact basin formed about 3.96 billion years ago, while lava flow from the volcano came later, about 3.7 billion years ago. Northeast Syrtis preserves the geological activity that occurred in the 250 million years between those two events. Billions of years of erosion, mostly from winds howling across the region into the Isidis lowlands, have exposed that history on the surface.

Within Northeast Syrtis are the mineral signatures of four distinct types of watery and potentially habitable past environments. Those minerals had been detected by prior research, but the new map shows in detail how they are distributed within the region’s larger geological context. That helps constrain the mechanisms that may have formed them, and shows when they formed relative to each other.

The lowest and the oldest layer exposed at Northeast Syrtis has the kind of clay minerals formed when rocks interact with water that has a fairly neutral pH. Next in the sequence are rocks containing kaolinite, a mineral formed by water percolating through soil. The next layer up contains spots where the mineral olivine has been altered to carbonate – an aqueous reaction that, on Earth, is known to provide chemical energy for bacterial colonies. The upper layers contain sulfate minerals, another sign of a watery, potentially life-sustaining environment.

Understanding the relative timing of these environments is critical, Mustard says. They occurred around the transition between the Noachian and Hesperian epochs – a time of profound environmental change on Mars.

“We know that these environments existed near this major pivot point in Mars history, and in mapping their context we know what came first, what came next and what came last,” Mustard said. “So now if we’re able to go there with a rover, we can sample rock on either side of that pivot point, which could help us understand the changes that occurred at that time, and test different hypotheses for the possibility of past life.”

And finding signs of past life is the primary mission of the Mars 2020 rover. NASA has held three workshops in which scientists debated the merits of various landing targets for the rover. Mustard and Bramble have led the charge for Northeast Syrtis, which has come out near the top of the list at each workshop. Last February, NASA announced that the site is one of the final three under consideration.

Mustard and Bramble hope this latest work might inform NASA’s decision, and ultimately help in planning the Mars 2020 mission.

“As we turn our eyes to the next target for in situ exploration on the Martian surface,” the researchers conclude, “no location offers better access of the gamut of geological processes active at Mars than Northeast Syrtis Major.”

TOP IMAGE…. A diverse landscape A false color image highlights the complex geology of the Northeast Syrtis Major region on Mars.
NASA/JPL/University of Arizona

LOWER IMAGE….A detailed map shows the the various geologic units exposed at Northeast Syrtis.
Credit: Mike Bramble/Mustard Lab


alicia: Surface of Mars, photographed by Mars Express, 3rd February 2008.

22 to 14°N, 78°E. Western edge of Isidis Planitia, east of the Syrtis Major highlands. This image is about 475 km long - for scale, Las Vegas is 426 km from San Diego, and Paris 492km from Zurich.

Produced from visible light imagery, although the combination is not likely to be naturalistic.

Image credit: ESA. Composite: AgeOfDestruction.

Hubble takes Mars portrait near close approach

Bright, frosty polar caps, and clouds above a vivid, rust-colored landscape reveal Mars as a dynamic seasonal planet in this NASA Hubble Space Telescope view taken on May 12, 2016, when Mars was 50 million miles from Earth. The Hubble image reveals details as small as 20 to 30 miles across.

The large, dark region at far right is Syrtis Major Planitia, one of the first features identified on the surface of the planet by seventeenth-century observers. Christiaan Huygens used this feature to measure the rotation rate of Mars. (A Martian day is about 24 hours and 37 minutes.) Today we know that Syrtis Major is an ancient, inactive shield volcano. Late-afternoon clouds surround its summit in this view.

A large oval feature to the south of Syrtis Major is the bright Hellas Planitia basin. About 1,100 miles across and nearly five miles deep, it was formed about 3.5 billion years ago by an asteroid impact.

The orange area in the center of the image is Arabia Terra, a vast upland region in northern Mars that covers about 2,800 miles. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest terrains on the planet. Dried river canyons (too small to be seen here) wind through the region and empty into the large northern lowlands.

South of Arabia Terra, running east to west along the equator, are the long dark features known as Sinus Sabaeus (to the east) and Sinus Meridiani (to the west). These darker regions are covered by dark bedrock and fine-grained sand deposits ground down from ancient lava flows and other volcanic features. These sand grains are coarser and less reflective than the fine dust that gives the brighter regions of Mars their ruddy appearance. Early Mars watchers first mapped these regions.

An extended blanket of clouds can be seen over the southern polar cap. The icy northern polar cap has receded to a comparatively small size because it is now late summer in the northern hemisphere. Hubble photographed a wispy afternoon lateral cloud extending for at least 1,000 miles at mid-northern latitudes. Early morning clouds and haze extend along the western limb.

This hemisphere of Mars contains landing sites for several NASA Mars surface robotic missions, including Viking 1 (1976), Mars Pathfinder (1997), and the still-operating Opportunity Mars rover. The landing sites of the Spirit and Curiosity Mars rovers are on the other side of the planet.

This observation was made just a few days before Mars opposition on May 22, when the sun and Mars will be on exact opposite sides of Earth, and when Mars will be at a distance of 47.4 million miles from Earth. On May 30, Mars will be the closest it has been to Earth in 11 years, at a distance of 46.8 million miles. Mars is especially photogenic during opposition because it can be seen fully illuminated by the sun as viewed from Earth.

The biennial close approaches between Mars and Earth are not all the same. Mars’ orbit around the sun is markedly elliptical; the close approaches to Earth can range from 35 million to 63 million miles.

They occur because about every two years Earth’s orbit catches up to Mars’ orbit, aligning the sun, Earth, and Mars in a straight line, so that Mars and the sun are on “opposing” sides of Earth. This phenomenon is a result of the difference in orbital periods between Earth’s orbit and Mars’ orbit. While Earth takes the familiar 365 days to travel once around the sun, Mars takes 687 Earth days to make its trip around our star. As a result, Earth makes almost two full orbits in the time it takes Mars to make just one, resulting in the occurrence of Martian oppositions about every 26 months.

memphis: Phobos over Mars, photographed by Rosetta, 24th February 2007.

Phobos, the larger of Mars’ two small moons, in orbit over 15°N 75°E. At bottom of the image are the Syrtis Major highlands, shading into the lighter Isidis Planitia lowlands. The lines at left are the Nili Fossae. (In this image, east is up.)

Rosetta is on the way to study comet 67P/Churyumov–Gerasimenko, which it will reach this summer, but its route included three fly-bys of earth, close encounters with two asteroids, and a fly-by of Mars. 

Image credit: ESA/MPS. Animation: AgeOfDestruction.