The Nakhla meteorite is much younger. It crystallized from lava about 1.3 billion years ago. And the clays in Nahkla are about 700 million years old. Because they're very different in chemical and mineral composition, Treiman reasons that 84001 and Nakhla must have come from different places on Mars because their ages are so different. As to whether Nakhla might contain traces of Martian life, that's a topic he's not yet ready to broach.
Nobody argues with that.
And to find out more about Nakhla and the other 12 known Martian meteorites, check out the JPL Mars Meteorite Home Page . Canada Inc. Discovery Canada 2001. All Rights Reserved.