6533b7d4fe1ef96bd12634fc

RESEARCH PRODUCT

Two Years at Meridiani Planum: Results from the Opportunity Rover

Wendy M. CalvinBenton C. ClarkScott M. MclennanJohn P. GrotzingerTimothy D. GlotchBradley L. JolliffMatthew P. GolombekNicholas J. ToscaHarry Y. McsweenSteven W. SquyresAndrew H. KnollWilliam H. FarrandGöstar KlingelhöferRaymond E. ArvidsonJames F. BellKenneth E. HerkenhoffJeffrey R. JohnsonAlbert S. Yen

subject

Meridiani PlanumGeologic SedimentsExtraterrestrial EnvironmentOutcropGeochemistryMarsMineralogyWeatheringengineering.materialFerric CompoundsTimeConcretionSpacecraftMineralsMultidisciplinarySulfatesSilicatesWaterHematitevisual_artengineeringvisual_art.visual_art_mediumHaliteSedimentary rockSiliciclasticAcidsGeology

description

The Mars Exploration Rover Opportunity has spent more than 2 years exploring Meridiani Planum, traveling ∼8 kilometers and detecting features that reveal ancient environmental conditions. These include well-developed festoon (trough) cross-lamination formed in flowing liquid water, strata with smaller and more abundant hematite-rich concretions than those seen previously, possible relict “hopper crystals” that might reflect the formation of halite, thick weathering rinds on rock surfaces, resistant fracture fills, and networks of polygonal fractures likely caused by dehydration of sulfate salts. Chemical variations with depth show that the siliciclastic fraction of outcrop rock has undergone substantial chemical alteration from a precursor basaltic composition. Observations from microscopic to orbital scales indicate that ancient Meridiani once had abundant acidic groundwater, arid and oxidizing surface conditions, and occasional liquid flow on the surface.

https://doi.org/10.1126/science.1130890