• DOI:10.1126/science.1228858
• Corpus ID: 206544554

Unique Meteorite from Early Amazonian Mars: Water-Rich Basaltic Breccia Northwest Africa 7034

@article{Agee2013UniqueMF,
  title={Unique Meteorite from Early Amazonian Mars: Water-Rich Basaltic Breccia Northwest Africa 7034},
  author={Carl B. Agee and N. V. Wilson and Francis M. McCubbin and Karen Ziegler and Victor J. Polyak and Zachary Sharp and Yemane Asmerom and Morgan H. Nunn and Robina Shaheen and Mark H. Thiemens and Andrew Steele and Marilyn L. Fogel and Roxane Bowden and Mihaela Glamoclija and Zhisheng Zhang and Stephen M. Elardo},
  journal={Science},
  year={2013},
  volume={339},
  pages={780 - 785}
}

• C. Agee, N. Wilson, +13 authors S. Elardo
• Published 15 February 2013
• Geology
• Science

So Different and So Similar Most known meteorites from Mars fit into one class. Agee et al. (p. 780, published online 3 January; see the Perspective by Humayun) describe a meteorite, NWA 7034, which shares some characteristics with other martian meteorites but does not fit within the usual classification. NWA 7034 matches the composition of Mars' surface but is also richer in water than other martian meteorites, and has different oxygen isotope composition, which suggests the existence of multiple oxygen isotopic reservoirs within Mars. Its radiometric age of 2.1 billion years makes it a unique sample of the Amazonian period on Mars. Detailed analysis of a meteorite shows that it matches the surface of Mars yet is unlike any other martian meteorite. [Also see Perspective by Humayun] We report data on the martian meteorite Northwest Africa (NWA) 7034, which shares some petrologic and geochemical characteristics with known martian meteorites of the SNC (i.e., shergottite, nakhlite, and chassignite) group, but also has some unique characteristics that would exclude it from that group. NWA 7034 is a geochemically enriched crustal rock compositionally similar to basalts and average martian crust measured by recent Rover and Orbiter missions. It formed 2.089 ± 0.081 billion years ago, during the early Amazonian epoch in Mars' geologic history. NWA 7034 has an order of magnitude more indigenous water than most SNC meteorites, with up to 6000 parts per million extraterrestrial H2O released during stepped heating. It also has bulk oxygen isotope values of Δ17O = 0.58 ± 0.05 per mil and a heat-released water oxygen isotope average value of Δ17O = 0.330 ± 0.011 per mil, suggesting the existence of multiple oxygen reservoirs on Mars.