Thursday, 17 September 2015

Teaching Geology - Visiting Thunder Rocks at Allegany State Park NY

I recently visited for the first time, Allegany State Park which is a large park within the Enchanted Mountains of Western New York State.  The park encompasses more than 65,000 acres of beautiful scenery and is located just north of Allegheny National Forest in Pennsylvania.  The park is divided into two sections:  The Red House and the Quaker Run Areas.

Visitors to the Park can enjoy winterized cabins, hiking, snowmobile trails, picnic and recreation areas, bike and horse paths, camping, boating, fishing and swimming.

Large boulders within Allegany State Park known as Thunder Rocks

A most interesting place within the Park to visit is a bedrock city named Thunder Rocks (called a city, because the massive boulders are the size of houses arranged slightly apart from each other so that it looks like there are streets running between them).  Rock city is a grouping of sedimentary rocks made up of Olean conglomerate.  The conglomerate is made of coarse sand and white quartzite pebbles.  The rocks sit on the Allegheny Plateau at 2,260 feet above sea level.    

Made up of huge rocks that one can walk amongst or even climb, Rock City is a great place to learn about geology, although I have heard several different theories about how the rocks got here.

At first glance, most individuals believe that glaciers brought the rocks to this area.  However, geologists have discovered that this small area of New York State has not been touched by glaciers, so that is false.

Some say that they were moved here from the nearby Catskill Mountains by erosion and gravity.  Millions of years ago, this area was covered by a large, shallow sea.  The Catskill Mountains were formed to the east at this time.   Rock city sits on a conglomerate known as the Devonian Salamanca conglomerate.  Conglomerate rock is individual stones cemented together.  The theory is that conglomerate is being carried downhill by soil creep that has been going on for thousands of years.

Another explanation is that continental collision formed the elevated Allegheny Mountains.  Erosion is uncovering ancient Paleozoic rocks, the youngest of which are Thunder Rocks.  In short, this theory says that Thunder Rocks are native bedrock and sit where they were deposited as sediments millions of years ago.

Note:  “Allegheny” is how the name of the National Forest and mountains are spelled in Pennsylvania.  In New York it is spelled “Allegany”.

And finally, there is an Iroquois legend that states that there once was a struggle amongst the guardian spirits of rocks to see who was the strongest.  They challenged each other to see who could throw the largest rock to the top of a mountain.  The Iroquois tribe close by heard thunderous noises coming from the mountain. Upon investigation they discovered the “thrown” rocks and named them “Thunder Rocks”.

Teaching Ideas:
Take a field trip to the Park to visit Thunder Rocks.  Students may walk amongst the rocks, but take care to discuss the dangers of climbing these high structures.  Since a field trip to the Park to see the rocks may not be possible, you may wish to download images of the park and rocks from FreeTiiuPix to use as part of your geography curriculum studies. 

New York State - Allegany Park
FreeTiiuPix-Download free images of Thunder Rocks