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Maya and Climate Climate has affected the vitality of many different societies in the past, as shown by numerous records across the globe and throughout human history. One of the most obvious and spectacular examples of this is from the Classic Maya civilization, whose advanced culture left highly detailed records of all aspects of their existence between 300 and 1000 C.E. Kennett et al. (p. 788 ; see the cover) present a detailed climate record derived from a stalagmite collected from a cave in Belize, in the midst of the Classic Maya settlement. The fine resolution and precise dating of the record allows changes in precipitation to be related to the politics, war, and population fluctuations of the Mayans.

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 H(2)O released during stepped heating. It also has bulk oxygen isotope values of Δ(17)O = 0.58 ± 0.05 per mil and a heat-released water oxygen isotope average value of Δ(17)O = 0.330 ± 0.011 per mil, suggesting the existence of multiple oxygen reservoirs on Mars.

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