Amazonian chemical weathering rate derived from stony meteorite finds at Meridiani Planum on Mars.
Spacecraft exploring Mars such as the Mars Exploration Rovers Spirit and Opportunity, as well as the Mars Science Laboratory or Curiosity rover, have accumulated evidence for wet and habitable conditions on early Mars more than 3 billion years ago. Current conditions, by contrast, are cold, extremely arid and seemingly inhospitable. To evaluate exactly how dry today's environment is, it is important to understand the ongoing current weathering processes. Here we present chemical weathering rates determined for Mars. We use the oxidation of iron in stony meteorites investigated by the Mars Exploration Rover Opportunity at Meridiani Planum. Their maximum exposure age is constrained by the formation of Victoria crater and their minimum age by erosion of the meteorites. The chemical weathering rates thus derived are ∼1 to 4 orders of magnitude slower than that of similar meteorites found in Antarctica where the slowest rates are observed on Earth.
Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK.
Christian
C
Schröder
Department of Applied Geology, Curtin University, Perth, Western Australia 6845, Australia.
Phil A
PA
Bland
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.
Matthew P
MP
Golombek
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.
James W
JW
Ashley
Department of Geological Sciences, State University of New York at Geneseo, Geneseo, New York 14454, USA.
Nicholas H
NH
Warner
Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, District Of Columbia 20560, USA.
John A
JA
Grant