References and Links Mars image

Meteorites are extremely rare, and Martian meteorites rarer still. Of the 21,000 meteorites known to exist, only 14 -- or 0.07% -- are Martian in origin. This page provides a few links and provides a bibliography of several studies on Martian meteorites.

As it regards the sample of Mars contained in Planet Mars: it was on October 3, 1962, that a very unusual meteorites streaked through our atmosphere and landed near the Zagami Rock formation in Nigeria. As meteorites are named after the locale to which they are "delivered," the vial embedded within the enclosed Lucite cube contains 1/10 carat of what is simply known as ZAGAMI.

Pointing to an "otherworldly" origin, Zagami has an unusually young crystallization age (so it can't be from Earth), contains water-bearing minerals (so it can't be from the asteroid belt), and evidences a planetary-sized gravitational field on its crystalline structure. Its link to Mars was not verified, however, until a recent analysis of Zagami revealed that gas trapped within its matrix matched the signature of the Martian atmosphere. Scientists concur Zagami was blasted into space when a huge asteroid slammed into the Martian surface. Based on cosmic ray absorption analysis, it is estimated that this event occurred nearly three million years ago. Zagami is one of only two meteorites to contain the atmosphere of Mars.

Zagami is a shergottite, principally a pyroxene-rich (mostly pigeonite and augite) igneous rock whose plagioclase was converted to a glass (maskelynite) as a result of an immense shock -- mostly likely created by the asteroid that launched this fragment into space.

References

AP. (March 31, 1995) Bit of Mars Hit Africa in '62 Researchers Say. The New York Times No. 50,017. A16


Bogard D.D., Johnson P. and Nyquist L.E. (1984a) Cosmic ray exposure of SNC achondrites and constraints on their derivation from Mars. (abs) Lunar Planet. Sci. XV, 68-69.

Bogard D.D., Nyquist L.E. and Johnson P. (1984b) Noble gas contents of shergottites and implications for the Martian origin of SNC meteorites. Geochim. Cosmochim. Acta 48, 1723-1739.

Eugster O., Weigel A. and Polnau E. (1996) Two different ejection events for basaltic Shergottites QUE94201, Zagami and Shergotty (2.6 Ma ago) and lherzolitic Shergottites LEW88516 and ALHA77005 (3.5 Ma ago). (abs) Lunar Planet. Sci. XXVII, 345-346.

Hamilton V.E. and Christensen P. R. (1996) Determining the composition of Mars: Vibrational spectroscopy of the Zagami meteorite. (abs) Lunar Planet. Sci. XXVII, 481-482.

Harper C.L., Nyquist L.E., Bansal B., Wiesmann H. and Shih C.-Y. (1995) Rapid accretion and early differentiation of Mars indicated by 142Nd/144Nd in SNC meteorites. Science 267, 213-217.

Leshin L.A., Epstein S. and Stopler E.M. (1996a) Hydrogen isotope geochemistry of SNC (Martian) meteorites and the history of water on Mars. (abs) In Workshop on evolution of Martian volatiles. (eds. Jakosky and Treiman) LPI Tech. Rpt. 96-01, 30-31. LPI, Houston.

Marti K., Kim J.S., Thakur A.N., McCoy T.J. and Keil K. (1995) Signatures of the Martian atmosphere in glass of the Zagami meteorite. Science 267, 1981-1984.

McCoy T.J. and Lofgren G.E. (1996) The crystallization of the Zagami shergottite: A 1 atm. experimental study. (abs) Lunar Planet. Sci XXVII, 839-840

Nyquist L.E., Bansal B., Wiesmann H. and C.-Y. Shih (1995) "Martians" young and old: Zagami and ALH84001. (abs) Lunar Planet Sci. XXVI, 1065-1066.

Stolper E.M. (1980) Trace elements in shergottite meteorites: Implications for the origins of planets. Earth Planet. Sci. Lett. 42, 239-242.

Tatsumoto M. and Premo W.R. (1988) U-Th-Pb, Sm-Nd, Rb-Sr and Lu-Hf systematics of returned Mars samples. In Workshop on Mars sample return science. (eds. Drake et al.) LPI Tech. Rpt. 88-07, 167-168. LPI, Houston.

Treiman A.H. (1995a) SNC: Multiple source areas for Martian meteorites. J. Geophys. Res. 100, 5329-5340.

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