Oklahoma's number one blog for natural and cultural history.

 

Inside the Treasure Box: Week Four

Last Wednesday, we suggested that you brush up on your prehistoric history for today’s post. You did, right? Perfect. For today’s ITTB, we’re going back in time. Way back in time, to the formation of the bygone supercontinent Pangea.

Let’s go back about 310 million years ago, in what is now the state of Rhode Island, where the landscape once supported lush, tropical forests. Leaves from the tropical vegetation would fall into the mud and be buried. Over time, as the mud turned to rock, the leaves left imprints in the form of fossils. The specimen below, from the paleobotany/micropaleontology collection, illustrates just that.

The imprint of a a Pecopteris leaf

Now, during this time, continents were colliding to form the supercontinent Pangaea, and these massive collisions very slowly stretched and bent the Rhode Island rocks caught in between. Usually, stretching and bending destroys fossils, but if the stretching is not too great, fossils survive to provide evidence of what happened. Such is the case with this specimen.

The supercontinent Pangea

 In this rock, we see the imprints of distorted Pecopteris leaves on the surface. Some leaves are short and wide, while others are long and narrow. Upon measuring, we find the long leaves are about 3.3 times longer than short leaves, and the wide leaves are about 3.3 times wider than the narrow leaves. With this evidence, we know the rocks were stretched to over 300 percent of their original size.

The stretched imprint

Pretty fascinating, don’t you think? We certainly do. Now, we’ve got another amazing specimen lined up for next week, but we’re not telling! It involves an exceptionally rare insect and a little etymology. Think you know what it is? Jump over to our Facebook page and give us your best guess, then tune in next week to see if you’re correct! Now, it looks like you’ve got brainstorming to do. We’ll meet you here next week. Same place, same time.