AMAZING FACTS ABOUT THE CAMBRIAN PERIOD
The CAMBRIAN PERIOD is the name we give to the time 541-485 million years ago. That is eight times longer ago than the end of the dinosaur age!
In the Ediacaran Period, before the Cambrian Period, complex life began. Many new life forms seem to have emerged. In the Cambrian Explosion, this took a quantum leap ...
Back then, there was much more ocean surface. There were continents in the southern hemisphere, but no life on land. No ozone layer meant solar radiation was high.
There were 21 hours in a Cambrian day, 410 days in a Cambrian year.
All Cambrian life was in the ocean, on the shallow sea shelves around the land. The bottom of these shelves was covered with a thick layer of microbes, “microbial mats”. This was the food that early sea creatures loved to eat.
These “mats” were changing the air, raising the oxygen level. But the Cambrian atmosphere had only 2/3 today’s oxygen, and six times the carbon dioxide.
Most sea creatures at the time were only a few cm long, but some got as big as 1 metre! Most were “arthropods”, meaning they had skeletons on the outside. There were many kinds. The most famous are Trilobites.
There was some plant life: algae, lichens ... and perhaps some plant-like Pre-Cambrian microbe formations remained called Charnia. (Perhaps!)
Before the Cambrian/Ediacaran periods, Earth might have been one big “snowball” ..Then came successive eras of global melting ... The ocean was rising, the continents flooding ...
The Cambrian/Ediacaran warming was probably caused by extreme volcanic activity ... During this 150-million-year era, the Earth got warmer, warmer, warmer ...
The global warming that coincided with the Cambrian Explosion might have gone too far & led to a mass extinction at the end of the era. Some clues point to ocean oxygen depletion. This is a mystery that Science is still working to uncover.
Today: some Cambrian sea-creatures are preserved as fossils. Amazing fossils have been found high in the mountains, like in the Burgess Shale in Yoho National Park, BC, Canada.
BUT, 508 million years ago, the Burgess Shale was an equatorial sea bed, 400 km offshore, at the base of an underwater escarpment ... teeming with life!
... This is the world of RELLA’S CAMBRIAN DREAM.