Sandstone is derived from consolidated sedimentary rocks of Mississippian through Pennsylvanian age from unconsolidated sediments of Quaternary age. Mississippian rocks were deposited as sediment 350 million years ago in the bottom of a warm, shallow sea. At the end of the Mississippian Period, 320 million years ago, the seas receded and sediments of the Pennsylvanian Period was deposited. The warm climate of the Pennsylvanian allowed extensive forests and great coastal swamps to form at the edges of water bodies. Marine waters advanced and receded many times, which produced many layers of sandstone. Over the last million years, unconsolidated Quaternary sediments have been deposited along the larger streams and rivers.
The bluffs in question is part of Tar Springs Sandstone. As the name of sandstone comes from a petroleum issue from its base. It is 55 ft. thick and consists of massive cliff-forming. Brown in lower part due to petroleum staining, snowy white in places in upper part. Sandstone is a sedimentary rock composed of sand-sized grains of mineral, rock or organic material. Like sand, sandstone may be any color, but the most common color are tan, brown, yellow, red, gray, pink, white and black. Since sandstone beds often form highly visible cliffs. Rock formations that are primarily composed of sandstone usually allow percolation of water and other fluids and porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. As being porous sandstone can be subject to weathering. This will take you the GZ of the largest overhang of sandstone and several rocks and one massive rock fallout.
The Forces of Weathering
Water is an important force that greatly effects weathering, but it is not the only force. Other forces include the atmosphere, and plant and animal life. The atmosphere is comprised of many different types of gases. These gases are able to penetrate into the openings of rocks. Plant roots, microscopic animals and plants, and digging animals also help to break down rocks. To better understand the different forces that causes weathering, geologists separate them into three categories. These categories are mechanical, chemical and biotic.
Mechanical Weathering
Takes place when rocks are broken down without any change in the chemical nature of the rocks. The rocks are essentially torn apart by physical force, rather than by chemical breakdown. The forces that break rocks down can be numerous, and include such things as pent up energy as the Earth's crust slowly moves. When great amounts of pressure build up, the resulting mechanical effect can be that very large joints or faults are created. The most common type of mechanical weathering is the constant freezing and thawing of water. In liquid form, water is able to penetrate the many holes, joints and fissures within a rock. The result is that the holes and cracks in rocks are pushed outward. Even the strongest rocks are no match for this force. As the water thaws, it is then able to penetrate further into the widened space, where it later freezes yet again. The expansion of holes and cracks is very slow.
Chemical Weathering
Takes place in almost all types of rocks. Chemical reactions break down the bonds holding the rocks together, causing them to fall apart, forming smaller and smaller pieces. Chemical weathering is such more common in locations where there is lot of water. This because water is important to many of the chemical reactions that can take place. Warmer temp. are also more friendly to chemical weathering. The most common types of chemical weathering are oxidation, hydrolysis and carbonation.
Oxidation takes place when oxygen combines with other elements in rocks to form new types of rock. These new substances are usually much softer, and thus easier for other forces to break apart. Hydrolysis occurs when water combines with the substances in the rocks to form new types of substances, which are softer than the original rock types. This allows other forces, such as mechanical weathering, to more easily break them apart. Carbonation takes place when carbon dioxide reacts with certain types of rocks forming a solution that can easily be carried away by water.
Biotic Weathering
The word 'bio' means life. Thus biotic weathering is any type of weathering that is caused by living organisms. Most often the culprit of biotic weathering are plant roots. Thes roots can extend downward, deep into rock cracks in search of water, and nutrients. In the process they act as a wedge, wielding and extending the cracks. Other causes of biotic are digging animals, microscopic plants and animals, algae and fungi.
Located on Tar Springs Road on the outskirts of Cloverport. This earthcache will bring you to the bluffs overlook Clover Creek. As you approach the EC walk the hill at a diagonally angle. Shouldn't be anymore than 30 ft up. Close to the road and parking down from GZ. Watch your step and any little cachers with you. Now question and answers. Make sure to email me the answer do not put on the log it will deleted.
1.What type of weathering do you think transpired at this area. Why.
2.How many cracks do you count on the overhang at GZ.
3. How many broken rock pieces do you count on the ground at GZ.
4. What is the texture of the wall.
5. What do you think the biggest rock looks like.
(Optional-Please take a pic of yourself here.)
