Meteorites on Mars observed with the Mars Exploration Rovers

Abstract

Reduced weathering rates due to the lack of liquid water and significantly greater typical surface ages should result in a higher density of meteorites on the surface of Mars compared to Earth. Several meteorites were identified among the rocks investigated during Opportunity's traverse across the sandy Meridiani plains. Heat Shield Rock is a IAB iron meteorite and has been officially recognized as “Meridiani Planum.” Barberton is olivine‐rich and contains metallic Fe in the form of kamacite, suggesting a meteoritic origin. It is chemically most consistent with a mesosiderite silicate clast. Santa Catarina is a brecciated rock with a chemical and mineralogical composition similar to Barberton. Barberton, Santa Catarina, and cobbles adjacent to Santa Catarina may be part of a strewn field. Spirit observed two probable iron meteorites from its Winter Haven location in the Columbia Hills in Gusev Crater. Chondrites have not been identified to date, which may be a result of their lower strengths and probability to survive impact at current atmospheric pressures. Impact craters directly associated with Heat Shield Rock, Barberton, or Santa Catarina have not been observed, but such craters could have been erased by eolian‐driven erosion.

Caracterização microestrutural de um provável fragmento do meteorito Itutinga

“…O valor obtido está razoavelmente próximo do intervalo de variação de densidade para os meteoritos metálicos, qual seja, 7,7 e 7,9g/cm³ (Sears, 1978 (De Souza, 2004), empregando-se um conjunto de sítios lorenztianos. Esse modelo de espectrô-metro Mössbauer está sendo empregado na caracterização da superfície de Marte (Klingelhoefer, 2003), incluindo meteoritos (Schroeder, 2008 (Stevens et al, 1982).…”

Zero-valent iron on Mars: An alternative energy source for methanogens

“…Oze and Sharma (2005) also presented a possible subsurface geochemical source for H 2 , although it is not known if their assumed environmental conditions actually exist within Mars' crust. However, the actual existence of zero-valent iron on Mars and in meteorites of martian origin have been confirmed (van de Moortèle et al, 2007;Pieters et al, 2008;Schröder et al, 2008;Kurihara et al, 2009). Zero-valent (''elemental", ''metallic") iron has also been shown to act as an electron source for eventual methanogenic metabolism by shuttling electrons to available protons which react to form usable H 2 (Daniels et al, 1987).…”

“…Fe/Ni meteorites composed mainly of Fe 0 have been discovered on the martian surface by both the Spirit and Opportunity rovers (Schröder et al, 2008). Stony-iron meteorites containing substantial Fe 0 were also discovered in what might be a strewn field (Schröder et al, 2008).…”

Extraterrestrial Mössbauer spectroscopy: more than 3 years of Mars exploration and developments for future missions

“…The chemical composition was rich in Mg and Ni and poor in Al and Ca, unlike any other martian material investigated thus far. The unusual chemical composition together with the metallic Fe component make a meteoritic origin much more likely than a martian origin, and this rock dubbed Barberton may be the first stony meteorite discovered on the surface of Mars [24].…”