Tharsis Montes

Tharsis Montes
NASA / JPL-Caltech / Arizona State University · Public domain · source
Name	Tharsis Montes
Location	Tharsis (region), Mars
Type	Shield volcanoes
Discovery	Giovanni Schiaparelli observations
First observed	19th century

Tharsis Montes is a group of three large shield volcanoes on Mars located near the western margin of the Tharsis (region). The trio dominates Martian topography and lies west of Valles Marineris and east of Noctis Labyrinthus, forming a prominent volcanic province visible from orbit by missions such as Mariner 9, Viking Orbiter, and Mars Reconnaissance Orbiter. These edifices are central to hypotheses linking Martian volcanism with planetary thermal evolution, atmospheric change, and potential astrobiological habitats studied by teams from NASA, European Space Agency, and other institutions.

Overview

The three volcanoes—often referred to individually in early literature—rise thousands of meters above the surrounding plateau and are aligned roughly northeast–southwest across the Tharsis (region). Their scale compares with large terrestrial constructs such as Mauna Loa and Olympus Mons in discussions by researchers from Jet Propulsion Laboratory and Smithsonian Institution. The cluster has been imaged repeatedly by spacecraft including Mariner 9, Viking Orbiter, Mars Global Surveyor, Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, and MAVEN, informing maps produced by USGS planetary cartographers and studies published in journals like Icarus and Journal of Geophysical Research: Planets.

Geology and morphology

Each shield displays low slopes and extensive lava flow fields typical of effusive eruptions analyzed in comparative studies with Hawaiian–Emperor seamount chain volcanism. Morphological features include summit calderas, radial rift zones, flank fissures, and lava flow lobes mapped with instruments such as HiRISE, CTX, and THEMIS. Secondary features associated with impact modification and mass wasting have been correlated with datasets from Mars Orbiter Laser Altimeter and gravity models from Mars Global Surveyor and Mars Reconnaissance Orbiter. Stratigraphic relations tie the shields to broader Tharsis volcanism, tectonic graben systems like Noctis Labyrinthus, and regional wrinkle ridges evaluated by planetary geologists at institutions including Caltech and Brown University.

Formation and evolution

Models for the genesis of these shields invoke mantle plume hypotheses advanced in the context of terrestrial plume work by researchers influenced by concepts from W. Jason Morgan and subsequent mantle dynamics studies. Alternative approaches emphasize lithospheric flexure, stress field evolution tied to Tharsis loading, and hotspot migration constrained by crater counting from Crater Analysis Techniques (CRaTER) and surface dating methodologies used by teams at Arizona State University. Thermal history reconstructions integrate data from mineralogical mapping by OMEGA and CRISM, and geochemical inferences from meteoritic analogs such as SNC meteorites studied by laboratories at Lunar and Planetary Institute.

Volcanic activity and petrology

Petrologic interpretations draw on spectral detections of basaltic compositions and altered phases, with comparisons to terrestrial basalt suites cataloged by researchers at USGS and petrology groups at MIT. The shields exhibit a range of inferred lava viscosities, eruption rates, and effusion volumes constrained by flow morphology studies using datasets from MOLA and thermal imaging from THEMIS. Though commonly considered predominantly basaltic, localized silicic and evolved compositions have been proposed in analogies to volcanic provinces like Colima and studies by the Geological Society of America. Geochemical models incorporate volatile budgets relevant to degassing studies pursued by NASA and ESA teams evaluating past atmospheric contributions.

Atmospheric and climate interactions

Tharsis loading is central to scenarios in which volcanic outgassing influenced the ancient Martian atmosphere and transient climate states explored in climate modeling by groups at University of Arizona and Oxford University. Simulations coupling outgassing of gases such as CO2 and H2O with atmospheric escape processes measured by MAVEN suggest episodes of greenhouse warming potentially linked to valley network formation investigated by researchers at Brown University and Caltech. Present-day interactions include dust lifting from flank slopes observed by Mars Reconnaissance Orbiter and orographic cloud formation documented by Mars Global Surveyor and ground-based telescopes like Palomar Observatory.

Exploration and observations

The Tharsis shields have been primary targets for orbital remote sensing from missions including Mariner 9, Viking Orbiter, Mars Global Surveyor, Mars Reconnaissance Orbiter, Mars Odyssey, Mars Express, and MAVEN. High-resolution imaging from HiRISE and spectral data from CRISM and OMEGA have driven field-analogue studies at terrestrial locales such as Hawaii and Iceland coordinated by institutions including NASA Ames Research Center and USGS. Proposals for in situ exploration and sample return have been considered by mission concept teams at ESA, NASA JPL, and academic consortia, linking to broader programs like Mars Sample Return planning.

Cultural significance and naming

Nineteenth-century observers such as Giovanni Schiaparelli and later commentators in planetary cartography contributed to the naming conventions adopted by the International Astronomical Union. The volcanoes have appeared in popular culture and speculative fiction referencing Martian topography in works associated with authors discussed in outlets like Science News and analyzed by scholars at Smithsonian Institution exhibitions. Ongoing nomenclature and historical studies intersect with archival holdings at Royal Astronomical Society and collections at Library of Congress.

Category:Surface features of Mars Category:Volcanoes on Mars