The 366 daily episodes in 2014 were chronological snapshots of earth history, beginning with the Precambrian in January and on to the Cenozoic in December. You can find them all in the index in the right sidebar. In 2015, the daily episodes for each month were assembled into monthly packages, and a few new episodes were posted. Now, the blog/podcast is on an occasional schedule with diverse topics, and the Facebook Page showcases photos on Mineral Monday and Fossil Friday. Thanks for your interest!

Saturday, February 1, 2014

February 1. The Cambrian begins.




The Proterozoic is done. We’ve started a new era, the Paleozoic, which means “ancient life” in Greek. It’s part of an eon, the Phanerozoic, that includes all the eras and all the time beginning with the Cambrian and continuing up to the present day. Phanerozoic means “visible life”, reflecting the former thought that there was no life before this time. We know now that there was earlier life, and some of it, like the Ediacarans, was certainly visible, but the name continues to be used. It works if you don’t worry too much about the literal Greek meaning.

The first subdivision of the Paleozoic is the Cambrian Period. Although there are older fossils, the Cambrian is the first time period when they are abundant, and this helped early geologists work out the sequence of rocks and the order in which they were laid down. A lot of that work was done in Great Britain.

Adam Sedgwick at the University of Cambridge is considered to be one of the founders of modern geology. He studied rocks in Wales, which was called Cambria by the Romans, from the Welsh name for their land, Cymru. In 1835, he gave the name Cambrian to the older series of rocks in the mountains of central Wales.

We’ll spend the month of February in the Cambrian.



No comments:

Post a Comment