Mabrey's Rock EarthCache
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Mabrey's rock is found inside the Guntersville State Park. It easily accessed from the rode and even handicap accessible with some caution for traffic.
This area of Alabama is referred to as the Cumberland Plateau. One of the things this area is known for is deep limestone deposits. The limestone in this area seems to be ideal for forming caves. This general area is well known for the number of caves located here. This rock is an example of the rock that is underground and sometimes is eroded into a cave. It is also an example of the rocks seen all over the park while hiking and exploring the many trails, cliffs, and stone outcroppings.There are three basic types of rocks found throughout the United States. Each type is formed in its own way. I hope through this Earth Cache to inform you about the types of rocks and how they are formed. Then it will be easy to indentify this rock and its origin. Igneous rocks are formed when molten lava, magma, crystallizes and solidifies. It is generally put under great pressure and is pushed above the Earth’s surface or near the surface. There are two types of Igneous rocks. Extrusive rocks are formed when molten lava is pushed above the Earth’s surface and it cools quickly. Crystals have little time to form and the rocks have very fine grains or a glassy texture. Pumice, obsidian, and basalt are all examples of extrusive igneous rocks. Intrusive rocks are formed when the molten lava cools deep beneath the Earth’s surface. The lava takes along time to cool and produces a rock with a course grain texture. Granite is an example of an intrusive igneous rock. Sedimentary rocks are rocks that are formed from other older rocks or parts from plants or animals. The deposits accumulate usually under water and as time passes the deposits settle and some natural pressure is applied and the loose materials form into rocks. These rocks often show distinctive layering. There are three groups of sedimentary rocks. Clastic Sediments are rock fragments that range from boulders to particles of silt and clay. Rocks are broken down from a process called weathering. These pieces are moved from running water usually until layers build up and then the lithification process begins. (stone forming process ). The pieces of stone and material are naturally cemented together to form rocks. Siltstone, shale, and sandstone are examples of Clastic sedimentary rocks. There is a rock that is a combination of types called a conglomerate stone. Biologic sedimentary rocks are formed when a large amount of living things die and pile up. The pieces are compressed and then naturally cemented into rock. Examples of this type of rock are coal, limestone, coquina, and chert. Chemical sedimentary rocks are formed from minerals left behind from where they dissolved in water and then the water evaporated causing the minerals to crystallize. Some Limestone beds are formed from calcite crystals and dissolved silica makes beds of flint rocks. Some other examples would be salt and stalagmites often seen in caves Metamorphic rock is rock that has changed its appearance and sometimes its mineral composition. Sedimentary rocks and igneous rocks can be changed into other types of rock. Metamorphic rocks are formed from exposure to high heat, high pressure, or hot mineral rich fluids. Most often it is from a combination of these conditions. There are two types of Metamorphic rocks. Foliated metamorphic rocks form when pressure aligns the minerals and they become elongated. The rocks have become sheet like or appear to be in plates. Slate, schist, and gneiss are all foliated metamorphic rocks. Non foliated metamorphic rocks do not have a sheet like structure. No matter how much pressure is applied, the minerals will not align to become flat or elongated. Rocks such as limestone and marble are examples of non-foliated metamorphic rocks. The information was taken from the World Book Encyclopedia and the US Geological Survey National Park Service web site.
1) Take a picture of yourself and your GPS and send in for proof of visit.
2) From the information above can you determine what type of rock this is?
3) Can you also determine what group of rock this would be classified as?
4) If you can not determine the group to classify the rock, simply estimate the height of the rock.
Additional Hints
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