Northeast Syrtis is a region of

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

once considered by

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...

as a landing site for the Mars 2020 rover mission. This landing site failed in the competition with

Jezero crater Jezero is a crater on Mars in the Syrtis Major quadrangle, about in diameter. Thought to have once been flooded with water, the crater contains a fan- delta deposit rich in clays. The lake in the crater was present when valley networks were for ...

, another landing site dozens of kilometers away from Northeast Syrtis. It is located in the northern hemisphere of Mars at coordinates 18°N,77°E in the northeastern part of the Syrtis Major volcanic province, within the ring structure of Isidis impact basin as well. This region contains diverse morphological features and minerals, indicating that water once flowed here. It may be an ancient habitable environment; microbes could have developed and thrived here. The layered terrain of Northeast Syrtis is unique on the surface of Mars, containing diverse aqueous minerals such as like

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...

, serpentine and

sulfate The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...

, as well as igneous minerals such as

olivine The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...

and high-calcium and low-calcium pyroxene. Clay minerals form in the interaction between water and rock and

sulfate minerals The sulfate minerals are a class of minerals that include the sulfate ion () within their structure. The sulfate minerals occur commonly in primary evaporite depositional environments, as gangue minerals in hydrothermal veins and as secondary mine ...

usually form through intense evaporation on Earth. Similar processes may happen on Mars forming these minerals, which strongly suggests a history of water and rock interaction. In addition, megabreccia, possibly the oldest material throughout this region (some blocks are over 100 m in diameter), could give an insight into the primary crust when Mars first formed. The location is an ideal site for studying the timing and evolution of the surface processes of Mars, such as huge

impact basin An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...

formation, fluvial activity ( valley networks, small

outflow channels Outflow channels are extremely long, wide swathes of scoured ground on Mars. They extend many hundreds of kilometers in length and are typically greater than one kilometer in width. They are thought to have been carved by huge outburst floods. ...

groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated ...

activity, history of

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...

, and

volcanic activity Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a ...

Regional stratigraphy

The regional stratigraphy of Northeast Syrtis has been studied in detail. This area is sandwiched between a huge shield volcano—Syrtis Major—and one of largest impact basins in the solar system, and therefore could provide a key constraint of the timing of key events in the history of Mars. The stratigraphy can be divided into four major units, from young to old: #Syrtis Major lavas unit contains high-calcium pyroxene bearing material; #Layered sulfate-bearing unit, include poly-hydrated sulfates and

jarosite Jarosite is a basic hydrous sulfate of potassium and ferric iron (Fe-III) with a chemical formula of KFe3(SO4)2(OH)6. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides. Jarosite is often produced as a byproduct du ...

; #Olivine unit, olivine-enriched unit variably altered to carbonate and serpentine; #Basement unit: The mixture of iron/magnesium (Fe/Mg)

smectite A smectite (from ancient Greek ''σμηκτός'' smektos 'lubricated'; ''σμηκτρίς'' smektris 'walker's earth', 'fuller's earth'; rubbing earth; earth that has the property of cleaning) is a mineral mixtures of various swelling sheet sil ...

and low-calcium pyroxene-bearing unit variably altered to Aluminium-clay bearing materials. The basement unit is one of newest units on Mars, recording early-stage evolution history of terrestrial planets. The change from carbonate to sulfate indicates a transition from alkaline-neutral to acid aqueous environments.

Mars 2020 mission

The Mars 2020 rover launched in July 2020 with

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Mart ...

rocket to reach Mars in February 2021. This rover inherits from the Mars Science Laboratory Curiosity, with similar entry, descent, and landing systems, and the sky crane. Besides exploring a likely habitable site and searching for signs of past life, collecting scientifically compelling samples (rock and

regolith Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestr ...

) which could address fundamental scientific questions if returned to Earth, is the main goal of the Mars 2020 mission. The landing site's selection is the key part of this mission's success. Although Northeast Syrtis survived the cut in third Mars 2020 Landing Site Workshops, it failed final completion. The landing ellipse of Northeast Syrtis is 16 x 14 km and the smaller ellipse is 13.3 × 7.8 km with the help of advanced technologyTerrain-Relative Navigation (TRN). NE Syrtis Ellipse

Region of interest

Mesa unit

The mesa is one of the interesting locations. It consists of five subunits: crater-retaining cap, boulder-shedding slopes exposing lightened blocks, olivine-carbonate unit, Fe/Mg-phyllosilicate, allowing easy to access diverse rocks. On the top of the mesa is a dark toned cap unit, composed of meter-scale boulders. It was interpreted as

Hesperian The Hesperian is a geologic system and time period on the planet Mars characterized by widespread volcanic activity and catastrophic flooding that carved immense outflow channels across the surface. The Hesperian is an intermediate and transitio ...

Syrtis Major lava flows or lithified ash. These igneous rocks are suitable samples for acquiring the age of Martian geologic events, which could calibrate the planet dating method. Unlike Earth, planet dating mainly relies on crater counting, a method based on the assumption that the number of impact craters on a planet surface increases with the length of time that the surface has been exposed to space cratering, calibrated using the ages obtained by radiometric dating of samples of Luna and Apollo missions. The samples of this mission returned to Earth will be analyzed by state of the art equipment in laboratories. Igneous samples from Northeast Syrtis could provide four key time for Martian geology history, including (1) the timing of Isidis impact event, (2) the timing of emplacement of olivine-rich unit, (3) the timing of dark-toned mafic cap rock, (4) the timing of Syrtis lava flows, which would fundamentally improve human knowledge of early Mars and the early history of solar system, such as the late-heavy bombardment. This region exposes the largest high-olivine abundance rocks on Mars. The origin of high-olivine rock is still in debate. Impact cumulates or olivine-rich lava are two leading hypotheses. A portion of olivine rock was altered to carbonate. Many hypotheses have been proposed to explain the origin of carbonate, including a serpentine springs system. Carbonate is important sink of carbon, and is a crucial part of understanding the

carbon cycle The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major componen ...

of Mars. Future sample return could shed light on the environmental conditions of carbonate. As well, the isotopic composition of carbonate through time, records the atmosphere loss, and it also reveals whether life once emerged on Mars. The lower part of mesa unit is the basement unit of the Northeast Syrtis region, consisting of Fe/Mg smectites and low calcium pyroxene. The basement unit was partially altered to form kaolinite. The kaolinite (Al-clay) usually overlying the Fe/Mg smectites across the Martian surface. Weathering in a warm climate or acid leaching are two domain interpretations of kaolinite formation.

= Megabreccia

Megabreccia occurs throughout the basement unit of Northeast Syrtis. The composition of these megabreccias is complex, including altered or mafic material. These megabreccias may be uplifted and exposed by the

Isidis Basin Isidis Planitia is a plain located within a giant impact basin on Mars, located partly in the Syrtis Major quadrangle and partly in the Amenthes quadrangle. At approximately in diameter, it is the third-largest obvious impact structure on the ...

forming event. The megabreccia could reveal the nature of the remnant of Mars's primary crust or the Noachian-aged low-calcium pyroxene lavas. It also could constrain the timing of Martian

dynamo "Dynamo Electric Machine" (end view, partly section, ) A dynamo is an electrical generator that creates direct current using a commutator. Dynamos were the first electrical generators capable of delivering power for industry, and the foundati ...

activity.

Layer sulfate unit

Further to the south of the landing ellipse, there is a thick sequence of

deposits capped by lava flows from the later Syrtis Major volcanic formation. The layer of sulfates include poly-hydrated sulphates and

Jarosite Jarosite is a basic hydrous sulfate of potassium and ferric iron (Fe-III) with a chemical formula of KFe3(SO4)2(OH)6. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides. Jarosite is often produced as a byproduct du ...

usually indicate oxidizing and acid (pH<4) environments. The occurrence of jarosite indicates that the environment changed from neutral/alkaline (as suggested by extensive Fe/Mg smectites and carbonate) to acid. The detection of sulfate adds more complexity to Martian geologic history.

References

External links

{{Geography of Mars Mars 2020 Syrtis Major quadrangle