New Hampshire Geology New Hampshire Bedrock Map

Permian Period
(290-245 million years ago)

One Big, Happy Family

For the previous hundred plus million years, North America and Africa had been on a slow collision course.  Finally, in the Permian Period [PURR-me-in] , the two continents are butted up against each other.  In the process, an ocean was closed up, intervening islands, ocean floor sediments and smaller continental plates were pasted on to North America and a mountain range that probably rivalled today's Himalayas were built.

What was going on in the rest of the world at this time?  At the same time that the North  American and African plates were on the move, so were all the other plates.  The fascinating aspect of all these plates on the move was that they were all heading into each other to create one giant land mass, called Pangea [pan-JEE-uh].

It's All Greek To Us

Pangea comes from two Greek words:

pan - meaning "all one", and
gea- meaning "Earth"

Therefore, Pangea translates into 'all one Earth'. To see if this makes sense, take a look at the map at right.

Prove it

How do we know that all of the land masses were together?  We don't know for sure, because human beings weren't around yet to witness this.  Harking back to the discussion in the Precambrian Period about theories; the nature of a theory is that it is an educated guess to explain something that is backed up by pieces of evidence.

The evidence in this case is found in the rocks. There are rock types and rock layers that are identical in Boston Harbor and North Africa, and in several other locations around the world that were next to each other.  There are similar fossils found in the rocks of continents that are now far apart from each other located in different climates from each other.  There are similar plant and animal types found in continents that are now far apart.  For example, have you ever noticed the similarities between a jaguar from South America and a leopard from Africa?

Permian Rocks In New Hampshire

The only Permian rocks created in New Hampshire are the same two-mica granites that started to form in the Carboniferous Period found near Conway and the Ossipee area as well as along the Mid-Massachusetts border area.

The Great Permian Extinction

Throught the course of Earth's history, there have been sudden mass extinctions of plants and animals as observed in the fossil record.  Several of these mass extiction episodes mark the boundaries of the geologic time periods.  Scientists have their theories, but no definite answers yet.  (See box at right.)

Whatever it was that caused the mass extinction that marked the end of the Permian Period, it was the most drastic extinction that ever occured.  Life on Earth was at its closest to ever being wiped out since it began.  More than 90% of all plant and animal species were wiped out.  This cleared the way for the reptiles to have their turn to dominate animal life on Earth for the next tens of millions of years.   That is until they were wiped out in their own mass extinction episode, which left the door open for mammals to develop as the dominant animal type.

Reading The Rocks

Wallis Sands Just as you can see the layers found in these rocks at Wallis Sands State Park (tipped up on their sides from continental collision), geologists have compared rock layers found on other continents and found similarities in rock types and layers.  Some of those rock types contain plant fossils that are identical on South America, Africa, Australia, India and Antarctica.  Since the seeds are too heavy to have blown across oceans, and these continents have very different climates today, scientists believe they must have been connected to each other at one time and shared a similar climate where this plant could have grown.

(Click on the image for a closer look.)|
Image credit: Daniel E. Reidy

Two-Mica Granite

conway granite Image credit: Daniel E. Reidy

Recall that granite usually forms with one kind of mica embedded in it.  (See "The Recipe For Granite" box in the Silurian Period page.)  What is special about the granite that formed during the Carboniferous and Permian Periods is that it contained two kinds of mica.  Here is what two mica granite looks like (from the Conway area):