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1. What kind of rocks are these and describe them ?
2. What is your Elevation at GZ ?
3.Estimate How High the rocks are ?
4.. How did the Rocks get here ?
5. Post a picture anywhere along the rocks .A new change to the guidelines allows me to require a photo. Take a picture of you or a personal item at the site.
The study of geology has put many pieces of a complex picture of Earth’s history together. The evidence of plate tectonics was largely accepted as explaining mountain building, sea-floor spreading and volcanism. In Pennsylvania, the geological history of our state includes several mountain-building episodes, of which, our Appalachian mountains are the last remnants of those ancient times. Collisions that pushed mountains upward were interspersed with periods of stretching apart of the solid crustal plates. When this stretching occurred the plates thinned or cracked apart allowing molten material to well up from deep below. If the upwelling happened quickly, volcanoes occurred. If the upwelling occurred slowly molten material rose but didn’t rise to the surface to produce volcanoes instead produced subsurface igneous intrusions – molten rock born from the heat of the earth which intrudes between other rocks already in place.
Conglomerate is a clastic sedimentary rock that contains large (greater than two millimeters in diameter) rounded clasts. The space between the clasts is generally filled with smaller particles and/or a chemical cement that binds the rock together. Conglomerate forms where a sediment of rounded clasts at least two millimeters in diameter accumulates. It takes a strong water current to transport and shape particles this large. So the environment of deposition might be along a swiftly flowing stream or a beach with strong waves. There must also be a source of large-size sediment particles somewhere up current. The rounded shape of the clasts reveal that they were tumbled by running water or moving waves.
Boxcar Rocks is probably one of the most impressive rock formations in the entire state of Pennsylvania. It is a sharp knife edged ridge which makes up a portion of the Sharp Mountain ridge-crest. Its name comes from the way the rocks sit together as they look like huge boxcars piled on top of each other when viewed from the north. Located about thirty miles to the northeast of Harrisburg, PA, this is a "must visit" summit in the greater Central Pennsylvania region. This area is also a climbing mecca and sees visitors from all over the state. The reason being that this is one of the only natural walls that provides anything worth attempting. The rock is also wonderful as it consists of a conglomerate with large quartzite pebbles mixed throughout. This allows for great hand and foot holds. The ridge is also nearly a quarter mile in length so there is no shortage of routes. The top of the ridge is a very thin knife edge with lots of little pinnacles rising up even higher and you must be very careful on windy days.
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