Category Archives: past worlds

How the air we breathe became breathable

Posted on November 15, 2007 by Chris Rowan

What geology tells us about the evolution of the Earth’s atmosphere.
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Categories: Archean, geochemistry, geology, paper reviews, past worlds, Proterozoic

Out of the ice age, into the asteroid shower

Posted on October 3, 2007 by Chris Rowan

Was the biggest cold snap in the last deglaciation caused by an extraterrestrial impact?
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Categories: climate science, geochemistry, geohazards, paper reviews, past worlds, planets, Pleistocene

Where the Moon was at, 3.2 billion years ago

Posted on July 13, 2007 by Chris Rowan

It may not look particularly cosmic, but the rock below not only tells us that the Moon was present back in the Archean, but also that it was orbiting the Earth at a much closer distance than it is today.

Categories: Archean, geology, paper reviews, past worlds

What is a greenstone belt?

Posted on July 12, 2007 by Chris Rowan

The Barberton greenstone belt – one of the oldest bits of crust on the planet
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Categories: Archean, fieldwork, geology, past worlds

Namibia: the stromatolites’ last hurrah

Posted on June 22, 2007 by Chris Rowan

Some of the more massive limestone beds in the Nama group are chock full of stromatolites, the remnants of sizeable Precambrian algal reefs. Technically, stromatolites are not true fossils, because the mineralised layers are not directly precipitated by the photosynthetic … Continue reading →