Surface composition of Mars
Pro Research Analysisby 
Searched over 200M research papers
Martian Surface Composition: Basaltic and Andesitic Materials
Mars’ surface is primarily composed of volcanic rocks, with two main types identified: basaltic and andesitic. The basaltic regions are dominated by plagioclase feldspar and clinopyroxene, while the andesitic areas contain plagioclase feldspar and volcanic glass. These compositions are distributed along the planet’s geological dichotomy, with basaltic rocks found on older surfaces and more silicic (andesitic) materials in the younger northern plains 110.
Surface Mineral Diversity: Mafic Silicates, Hydrated Minerals, and Sulfates
Mars shows a diverse and complex mineralogy. Both the northern and southern crusts contain mafic, iron-bearing silicates such as olivine and pyroxene. Localized concentrations of hydrated phyllosilicates (clay minerals) and sulfates have been mapped, especially in ancient terrains. However, carbonates are notably absent in most regions. The presence of these minerals indicates that Mars experienced significant water-related processes in its past, including weathering and hydrothermal activity 310.
Polar Caps: Water Ice and Carbon Dioxide Ice
The Martian polar regions are covered by different types of ice. The north polar cap is primarily composed of water ice, while the south polar cap is covered by a thin layer of carbon dioxide ice. Seasonal and temporal patches of water frost have also been observed, especially in the north 345.
Surface Layer Properties: Dust, Rock, and Aeolian Processes
Mars’ surface layer varies widely in its physical properties. There are three main types of surface materials: bright-red, low-inertia dust; dark-grey, high-inertia lithic material mixed with palagonite-like dust; and dark-red, moderate-inertia indurated material. Aeolian (wind-driven) processes have played a major role in shaping the surface, redistributing dust and forming crusts and fines of varying cohesion .
Elemental and Mineralogical Composition: In Situ and Orbital Measurements
Orbital and in situ measurements confirm that Mars’ upper crust is basaltic, with regional variations in plagioclase, pyroxene, and olivine content. Some areas, especially around large basins and in certain lava flows, are enriched in olivine. Alkali volcanic rocks are also present in specific regions, indicating differences in volcanic activity across the planet 810.
Hydrated Minerals and Evidence of Water
Hydrated minerals, such as clays and sulfates, are found in ancient Noachian crust and in sediments from paleolakes. These minerals provide strong evidence for widespread water activity in Mars’ early history. In more recent epochs, the presence of sulfates and silica in some locations suggests that water was locally available even in the planet’s later history 310.
Surface Dust and Bright Materials
The brightest materials on Mars are widespread and are mainly composed of fine-grained, highly oxidized dust, including ferric oxides and dessicated mineral hydrates. These bright materials are likely alteration products of the underlying basaltic or ultramafic rocks, formed through weathering and aeolian processes .
Conclusion
Mars’ surface is geologically diverse, with a basaltic crust, regional variations in volcanic and sedimentary rocks, and widespread evidence of past water activity. The planet’s surface materials include a mix of mafic silicates, hydrated minerals, sulfates, and oxidized dust, reflecting a complex history of volcanic, aqueous, and aeolian processes 13458910.
Sources and full results
Most relevant research papers on this topic