Ancient life in the Pilbara

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Ancient life in the Pilbara

This is a transcript of QuickTime movie (3.9 MB) recorded in the Pilbara in 2005. Dr Bruce Runnegar, Director of the NASA Astrobiology Institute, talks about how to look for ancient life in the Pilbara.


Here in the Pilbara there are two or three different ways to look for ancient life. One of which is to look for effects of life on sedimentary layers that were formed at the time and that's what we are doing here. The other two things you can do is to try and actually find the bodies of ancient microorganisms preserved in a particular kind of rock called chert which is a very finely grained silicon oxide. I am sitting on chert at the moment. It's a black material, it's glassy in appearance, it's very fine grained and we can cut it up into thin slices, thin enough so that you can see through them with a light microscope. You can hope to find the remains of ancient organisms in these cherts but that's very difficult and it hasn’t been easy to do, and the results we have are still controversial. The other thing you can do is to look at the chemicals that life produces and in particular the way they change the ratio of commodities called isotopes. That's a technical chemical problem which other people here are addressing. But at this particular spot what is really interesting is the structures that are formed in the layers of the sediment. These are structures that are big enough to see with the naked eye. Some of them are as big as a grapefruit. So they are the sorts of things you'd expect to see out of the window of Rover on Mars. And so if we can understand them here, we've got a chance of understanding similar bed forms on Mars.




Early Life



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