Geology Word of the Week: G is for Gondwana

Note: I started the Geology Word of the Week at Skepchick, where I am one of several fabulous, skeptical women (and one deserving man) bloggers. For the first few weeks of the Geology Word of the Week, I am going to re-post my "Geology Words of the Week(ish)" from Skepchick. Before being distracted by graduate school and life, I made my way from A to G... I will re-post those letters here and then continue with the rest of the alphabet. In 26 weeks, I will have made my way through the alphabet!

Gondwana Reconstruction. Image from Wikipedia Commons.

This week we are at the letter G… I immediately thought of one of my favorite geology words: Gondwana!


def. Gondwana:
Gondwana is an ancient geological supercontinent that was comprised of modern-day Antarctica, South America, Africa, Australia, New Zealand, India, and Arabia. Gondwana first formed ~500 million years ago and later joined with the supercontinent Laurasia, that was comprised of modern-day North America, Europe, and Asia, to form a super-supercontinent named Pangea. Subsequently, Pangea began breaking up ~175 million years ago. The first stage of that separation was rifting of Laurasia from Gondwana. Eventually, all of the modern-day continents formed and gradually moved (over the past ~175 million years) into their present positions.

I love thinking about past supercontinents and super-supercontinents. Think about how different the planet must have looked: one massive continent and one massive ocean only. Imagine trekking across that massive continent or trying to sail across that massive ocean– which was called Panthalassia, by the way. What great names: Pangea and Panthalassia. Imagine how much easier geography class must have been back then (purely hypothetically, that is, since there were no humans). No memorizing the 7 continents and various oceans in primary school. Just one land and one ocean to remember.

Pangea is not the only supercontinent in Earth’s history, just the most recent one. Geologists believe that there have been several cycles of supercontinents forming and breaking up. Of course, the further back one goes in geologic time the sparser the evidence (much is destroyed in cycles of continents forming and breaking up), so much less is known about these earlier supercontinents. However, geologists have given them very cool-sounding names: Pannotia, Rodinia, Columbia, Kenorland, Ur, and Vaalbara.

There are many neat animations on the web showing the formation and break-up of Pangea and other past supercontinents. Here is one animation I like.
 
If you like supercontinents like me, you can always dress up as your favorite supercontinent for that next costume party event, just as I did during my first year of grad school. Back then I actually used to go to parties, unlike now when I mostly prepare for committee meetings and try to submit papers. Sigh. Just be sure to remember your cape… you are a supercontinent after all! And be careful… your continents may tend to rift as the night proceeds.

Supercontinent Costume, Woods Hole, MA, Fall 2006.