What is Shale?
Shale is the most common sedimentary rock. Shale is a fine-grained sedimentary rock whose original constituents were clay minerals or muds. 'Black shales' are dark, as a result of being especially rich in unoxidized carbon. The vast extent of U.S. oil shale resources, amounting to more than 2 trillion barrels, has been known for over a century. As fossil fuels become scarcer, the oil deposits found in shale become economically feasible to recover. Oil shale has gained attention as an energy resource as the price of conventional sources of petroleum has risen and as a way for some countries to secure independence from external suppliers of energy.
Chattanooga Shale
What is the Chattanooga Shale? The Chattanooga Shale is a thick, widespread formation of shale heavily mixed with carbon, which gives the rock its black color. Although this particular deposit of Chattanooga shale is very close to city of Chattanooga, Chattanooga shale is found across much of central and eastern United States. Chattanooga shale deposits have been investigated for commercial oil and gas production in Tennessee and Kentucky. In some areas, the carbon content is so high that the rock has actually been burned as a heat source. Chattanooga shale also contains a significant amount of pyrite (FeS2 Iron Sulfide) also known as fools gold because of it’s color, which can resemble gold. When the Chattanooga Shale erodes, it releases sulfur into streams, increasing the water’s acidity. Chattanooga Shale also contains uranium and has been considered a low-grade vast reserve source for nuclear fuel.
When Did the Deposits occur?
Chattanooga Shale was deposited at the end of the Devonian Period (Approximately 416 to 359 million years ago.) These deposits came from sediment at the bottom of vast seas, although there are some arguments over just how deep the seas were. Do you see the various layers, or strata, visible in the rock face? They aren’t horizontal, are they? No, the various layers of earth and rock are angled. When these deposits were made on the sea floor, the layers were level with the sea floor, but now the shale is no longer horizontal. What forces do you think caused the shale to now be at angle?
In order to complete this earthcache as a find, you must complete all requirements below. Failure to comply will result in your log entry being deleted without notice.
Please complete the following:
1. When you log your visit, post a photo of an interesting feature at the coordinates with the shale deposit in the background. Of course, a photo of you would be appreciated but you do not have to be in the photograph.. Please send an email to LOSTNSPACE9@gmail.com with your best answers to the following questions: (Answers for 2. and 3. can be found in the material above.)
2. What gives the shale deposit it’s black color?
3. How long ago did the shale deposits begin to form?
4. Estimate how tall is the layer of shale found at these coordinates?
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