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!

Sunday, February 9, 2014

February 9. Pan-African Orogeny



You remember Rodinia, the supercontinent that assembled around a billion years ago and started to split apart again around 750 million years ago? Well, it’s time to put it back together again. At least some big pieces of it.



Yellow = West Gondwana, Lilac = East Gondwana
Near the end of the Proterozoic and into early Cambrian time, most of what we know as Africa today came together, along with some other important continental blocks. It wasn’t one big collision, but several collisions, which brought what is today central Africa, the Sahara, Congo, and Cape (or Kalahari) Cratons, together with east Africa, Arabia, Madagascar, India, and eventually Antarctica. That happened along a zone called the Mozambique Belt today.

At the same general time, South America and the West African craton were added on the other side of the Sahara-Congo-Cape continent. The final amalgamation, called the all-Africa, or Pan-African Orogeny, resulted in a supercontinent – not one involving all the continents, but pretty super nonetheless – that stayed pretty much intact for the next 350 million years. It’s named Gondwana.

You might have heard this called Gondwanaland – that’s how I learned it back in college – but Gondwana means “forest land of the Gonds,” so Gondwanaland is redundant. Who were the Gonds? They were – and still are – a native people of central India. Their homeland contains rocks that helped us understand the assembly and breakup of the supercontinent that now has the name Gondwana.

Don’t forget that while various continental pieces were coming together, in other parts of the world extension and pull-apart were happening. North America, for example, was pretty much going its own way during the Cambrian.
—Richard I. Gibson

Image from Wikipedia, public domain.


Further reading:
http://www.utdallas.edu/~rjstern/pdfs/PanAfricanOrogeny.pdf
Map

3 comments:

  1. I've really been enjoying the podcast. I went through most of January in one day. Looking forward to the rest of the year. I would like to get the book but I didn't have any luck trying to order it off the website.

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    Replies
    1. Thanks! for the book, you could just email me your info to rigibson@earthlink.net - sorry the order form didn't work.

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  2. I've really been enjoying the podcast. Very interesting. I went through most of January in one day. I'm looking forward to the rest of the year.

    ReplyDelete