They contain the minerals olivine, pyroxene, plagioclase, and magnetite, and they look like volcanic basalt as they are fine-grained with irregular holes (geologists would say they have vesicles and vugs).

[12] Plain's rocks have been very slightly altered, probably by thin films of water because they are softer and contain veins of light colored material that may be bromine compounds, as well as coatings or rinds.

One type of soil, called Paso Robles, from the Columbia Hills, may be an evaporate deposit because it contains large amounts of sulfur, phosphorus, calcium, and iron.

[29] After Spirit stopped working scientists studied old data from the Miniature Thermal Emission Spectrometer, or Mini-TES and confirmed the presence of large amounts of carbonate-rich rocks, which means that regions of the planet may have once harbored water.

[35] When the largest lake spilled over the low point in its boundary, a torrential flood would have moved north, carving the sinuous Ma'adim Vallis.

Space craft cameras showed that floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and traveled thousands of kilometers.

On the other hand, some of the large outflow channels begin in rubble-filled low areas called chaos or chaotic terrain.

[44][45]Gale Crater, in the northwestern part of the Aeolis quadrangle, is of special interest to geologists because it contains a 2–4 km (1.2–2.5 mi) high mound of layered sedimentary rocks.

[48] The lower formation may date from near the Noachian age, while the upper layer, separated by an erosional unconformity, may be as young as the Amazonian period.

[55][56][57] On December 9, 2013, NASA reported that, based on evidence from Curiosity studying Aeolis Palus, Gale Crater contained an ancient freshwater lake which could have been a hospitable environment for microbial life.

The aim of the Mars Science Laboratory mission, and its surface robotic payload Curiosity rover, is to search for signs of ancient life.

On September 27, 2012, NASA scientists announced that Curiosity found evidence for an ancient streambed suggesting a "vigorous flow" of water on Mars.

So far, the materials Curiosity has analyzed are consistent with the initial ideas of deposits in Gale Crater recording a transition through time from a wet to dry environment.

[85][86] Using SAM's mass spectrometer, scientists measured isotopes of helium, neon, and argon that cosmic rays produce as they go through rock.

These measurements are necessary for human missions to the surface of Mars, to provide microbial survival times of any possible extant or past life, and to determine how long potential organic biosignatures can be preserved.

[84][86] The two samples, John Klein and Cumberland, contain basaltic minerals, Ca-sulfates, Fe oxide/hydroxides, Fe-sulfides, amorphous material, and trioctahedral smectites (a type of clay).

[94] A Late Noachian/Early Hesperian or younger age indicates that clay mineral formation on Mars extended beyond Noachian time; therefore, in this location neutral pH lasted longer than previously thought.

[95][96][97][98][99] Also in December 2014, it was announced that Curiosity had detected sharp increases in methane four times out of twelve during a 20-month period with the Tunable Laser Spectrometer (TLS) of the Sample Analysis at Mars instrument (SAM).

[107][108] The Jet Propulsion Laboratory (JPL) announced in April 2015 the discovery of a network of two-tone mineral veins at an area called "Garden City" on lower Mount Sharp.

This finding used measurements from ChemCam, the Alpha Particle X-ray Spectrometer (APXS), and the Chemistry and Mineralogy (CheMin) instrument inside the rover.

[124] By using Curiosity's laser-firing device (ChemCam), scientists found manganese oxides in mineral veins in the "Kimberley" region of Gale Crater.

[125][126][127] A study of the kinds of minerals in veins examined with Curiosity found that evaporating lakes were present in the past in Gale crater.

[147][148][149][150] Studies of the wind around the Curiosity rover over a period of 3 billion years has shown that the Mount Sharp, the mound inside Gale Crater was created when winds removed material over billions of years and left material in the middle that is Mount Sharp.

[153][154] An analysis of a large amount of data from ChemCam and APXS showed that most of the material encountered by Curiosity consists of just two major igneous rock types and traces of three others.

After the layers were deposited, an acid solution may have moved through the rock, which contained olivine and pyroxene, dissolving some minerals like magnetite and forming new ones like hematite and jarosite.

[158][159] Research presented in a June 2018 press conference described the detection of more organic molecules in a drill sample analyzed by Curiosity.

Organic matter was from lacustrine mudstones at the base of the ~3.5-billion-year-old Murray formation at Pahrump Hills, by the Sample Analysis at Mars instrument suite.

CheMin has discovered olivine, pyroxene, feldspar, quartz, magnetite, iron sulfides (pyrite and pyrrhotite), akaganeite, jarosite, and calcium sulfates (gypsum, anhydrite, basanite) [166] Research presented in 2018 at the Geological Society of America Annual Meeting in Indianapolis, Indiana described evidence for huge floods in Gale Crater.

[171][172][173] Researched published in Nature Geoscience in October 2019 described how Gale crater underwent many wet and dry cycles as its lake waters disappeared.

Recent research with an orbiting near-infrared spectrometer, which reveals the types of minerals present based on the wavelengths of light they absorb, found evidence of layers of both clay and sulfates in Columbus crater.