Quote:
Originally Posted by Damien
Also layers of rock sedimentation and radiometric dating. The rock literally is laid as eras pass, and geologists can tell what the atmosphere was like to form it. (We knew something happened at the time the dinosaurs went extinct via this method, long before we found the crater).
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The CT boundary, in rocks below that level dinosaur fossils are numerous, above it, none. The boundary itself is marked by a thin deposit layer, over-rich in iridium. So obviously something catastrophic happened on a global scale some 65-66 million years ago, the increased iridium did suggest a metiorite impact, it was many, many years later that the likely candidate for the site was uncovered in. what is now, Mexico.
60-odd million years of erosion have erased most surface features, but there is considerable evidence from the shocked state of the rocks underground.
Now before I am accused of taking the thread off course, I am pointing out that it is certainly possible to deduce what happened or what the conditions were like long before humans kept records or even existed. The Earth has warmed and cooled many times over it’s history - but never so fast as we are seeing now.
So what is causing the mean global temperature to climb so fast? What happened in the world around 150 years ago? Coincidence, oir could there be a connection?