"Marine" Geology

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N/S ? ??.??? W/E ??? ??.???  [] In Pennsylvania, United States

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The "Whaleback" anticline in Bear Valley strip mine near Shamokin, Pa. is a natural laboratory for teaching structural geology. Bear Valley, located near Shamokin, Pennsylvania, is an abandoned coal strip mine in the Anthracite District. The site provides a spectacular exposure of tight folds in the Pennsylvanian Llewelyn Formation.

The Anthracite Upland is the most complex and most studied section in the state. This area is home to one of Pennsylvania's most profitable coal fields ever, containing high-grade Anthracite coal. Mountains are steep-sided and valleys are canoe-shaped, largely due to its complex folded structure. Other than coal, cyclical sequences of shale, sandstone, and conglomerate also make up this region. The rocks are from the Carboniferous period, divided into the Mississippian and Pennsylvanian periods with almost all of the coal being mined from Pennsylvanian-aged formations. Along with the Mazon Creek fossil field in Illinois, a tremendous amount of plant fossils have been studied from this area. Landsides and acid mine drainage are two principle hazards of the area. In the past, underground mine fires have also been a threat. The Centralia Mine Fire is located within this section.

Exposed by strip mining, the whaleback is quite large and distinctive. The rocks on top of it are the size of cars.

At the Bear Valley Strip Mine, a sequence of deformational stages of the Alleghany orogeny can be interpreted from overprinted structures in rocks of Pennsylvanian age. All of the stages displayed must be Pennsylvanian or younger but no Mesozoic deformation is thought to have occurred here. Rocks of the Bear Valley Strip Mine were deformed at temperatures of 185° to 205°C under an overburden of 3.1 to 5.0 mi (5 to 8 km)

To qualify as a "find", email (do not post online) the answers to the following questions:

1) Explain what geological structures combined to form the "whaleback".

2) What is the rock sequence in the Bear Valley strip mine? (ie. name several of the 7 specific rocks occuring here).

3) Why is the "whaleback" anticline significant in demonstrating structural geology?

4) UPLOAD a photo clearly showing the "whaleback" in the background with yourself and GPS.

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Logged Visits ( 10 total. Visit the Gallery (14 images) )

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Cache Logs

September 19 by ToTheMaxTimesFive (636 found) Great view of the whaleback! Luckily as we approached the site a whole bunch of ATVs were just leaving. There is a lot of very interesting geology in this region. Answered mailed. TFTC! [view this log] At Whaleback

June 26 by jbduhadaway (126 found) Did it, the email will follow. I have collected fossil ferns in the shale were the large anticline and the syncline meet. [view this log] Pittsburgh June 2009 425

May 7 by DANKREBS (166 found) Thanks for the Earthcache, I really enjoy these! I have been here many times since it is almost in my backyard! Wish we could clean the area up and make a nice sign and trail! TFTC! [view this log] Down @ The Whaleback!

June 18, 2008 by Rev Mike (3275 found) Found while out caching with littlebit and vinarian. Stopped off here on a long 1823 mile roadtrip. Had a heck of a time getting back here in a Scion. We had to stop just short of the lake the Carels drove through. Then it started raining a bit as soon as we got out of the car. Once we got there it was a sight to behold. Of all the caches on this trip this is the one I am most interested in returning to. You would not happen to know how to get legal access to the area? Great earthcache. Email sent and photos will be posted soon. - Rev Mike [view this log] Rev Mike, GPS, and whaleback

June 17, 2008 by vinarian (547 found) very nice earthcache, wonderful view, thanks for the cache! found with rev mike and littlebit had to post a picture of the cachemobile (perry) at almost the same spot as the carls (hummer?) [view this log] So the scion isnt quite a hummer :P nice view!

Current time: 11/21/2009 3:19:24 PM
Last Updated: 9/20/2009 1:17:08 AM
Rendered: From Database
Coordinates are in the WGS84 datum