Coprates Chasma

Coprates Chasma
Name	Coprates Chasma
Type	canyon
Location	Valles Marineris, Mars
Coordinates	13°S 60°W
Length	~960 km system (Coprates segment ~200–300 km)
Discovery	Mariner 9 era
Eponym	Coprates (river)

Coprates Chasma

Coprates Chasma is a large canyon segment within the Valles Marineris system on Mars. It forms a deep, elongate trough between plateau and canyon walls, linking to adjacent troughs and basins across the Tharsis Montes-adjacent region. Prominent in orbital imagery from missions such as Mariner 9, Viking program, and Mars Reconnaissance Orbiter, Coprates Chasma has been central to studies by teams at institutions including the Jet Propulsion Laboratory, the Lunar and Planetary Laboratory, and the Smithsonian Institution.

Geography and morphology

Coprates Chasma sits in the equatorial region near the Noctis Labyrinthus and the Ius Chasma–Melas Chasma corridor, bounded to the north by the Thaumasia Plateau and to the south by the Eos Chasma–adjacent terrains. The chasma exhibits steep escarpments, interior terraces, and a floor hosting mesa-like remnants related to the broader Valles Marineris trough network. Morphological features have been mapped by instruments on Mars Global Surveyor, Mars Odyssey, and Mars Express, revealing layered walls, mass-wasting deposits, and tectonic scarps correlated with regional structures described in studies from the American Geophysical Union and researchers at NASA Ames Research Center.

Geology and formation

Interpretations of Coprates Chasma's origin invoke combined processes: extensional rifting related to the emplacement of the Tharsis Montes volcanic province, catastrophic collapse events linked to crustal unloading, and erosional modification by fluvial or glacial agents. Structural analyses reference graben formation analogous to terrestrial rift systems studied in the East African Rift and the Rio Grande Rift, with comparative work led by planetary geologists at California Institute of Technology and Brown University. Evidence for volcanotectonic influence links to eruptive centers like Pavonis Mons and lava flow emplacement observed in context with regional maps produced by the US Geological Survey planetary cartography teams.

Stratigraphy and composition

Wall exposures in Coprates Chasma display stratified units interpreted as sedimentary, volcanic, and volcaniclastic deposits; orbital spectrometers aboard Mars Reconnaissance Orbiter’s CRISM and Mars Express’s OMEGA instrument have detected mineralogies including phyllosilicates associated with altered mafic materials and hydrated sulfates similar to deposits elsewhere in Margaritifer Terra and Meridiani Planum. Stratigraphic frameworks developed by groups at University of Arizona, University of Colorado Boulder, and Massachusetts Institute of Technology place these units within the broader Martian Noachian–Hesperian transition in regional chronologies used by the International Astronomical Union nomenclature committees.

Hydrology and paleoclimate evidence

Geomorphic indicators within Coprates Chasma—such as channel-like alcoves, layered deposits, and possible paleolake basins—have been compared to terrestrial analogs in the Atacama Desert, Antarctic Dry Valleys, and Greenland glacial margins by researchers affiliated with the European Space Agency and British Antarctic Survey. Mineral signatures of phyllosilicates and sulfates recorded by CRISM suggest aqueous alteration consistent with episodic surface or subsurface water activity during the Noachian and Hesperian epochs cited in publications from the Geological Society of America. Climate models developed at University of Oxford and Caltech attempt to reconcile these observations with transient warming scenarios influenced by impacts, volcanism, or greenhouse gas episodes constrained by datasets from the Curiosity and InSight missions.

Exploration and observations

Coprates Chasma has been imaged and analyzed by a sequence of missions: early reconnaissance by Mariner 9, high-resolution mapping by Viking Orbiter, topographic and thermal mapping by Mars Global Surveyor’s MOLA and TES instruments, thermal inertia and gamma-ray measurements from Mars Odyssey’s THEMIS and GRS, and high-resolution imaging and spectral mapping by Mars Reconnaissance Orbiter’s HiRISE and CRISM. Field-analog studies by teams at Brown University, University of Southern California, and the Natural History Museum, London have used Earth analog sites to interpret erosional and depositional histories, while mission science teams at NASA JPL continue to publish targeted analyses.

Comparative context within Valles Marineris

Within the Valles Marineris complex, Coprates Chasma is compared to adjoining chasmata such as Candor Chasma, Melancholia-adjacent features, Tithonium Chasma, and Noctis Labyrinthus in terms of depth, stratigraphy, and modification history. Comparative geomorphology draws on terrestrial rift comparisons like the Basin and Range Province and on Martian regional syntheses by consortia at European Space Agency and NASA centers. Differences in mineral assemblages and floor morphologies inform hypotheses about local versus regional drivers of canyon evolution discussed in literature from the Planetary Science Institute.

Cultural references and nomenclature

The name derives from the classical river Coprates as used in historical geographies cataloged by the International Astronomical Union; the feature’s naming and mapping are recorded in planetary gazetteers curated by the US Geological Survey and the IAU Working Group for Planetary System Nomenclature. Coprates Chasma has been depicted in educational exhibits at institutions such as the Smithsonian Institution National Air and Space Museum and in popular science media produced by BBC and National Geographic that discuss Martian canyons in the context of exploration histories including Mariner 9 and the Mars Reconnaissance Orbiter program.

Category:Valles Marineris Category:Valleys and canyons on Mars