The listed coordinates will bring you to the boardwalk at the Stonewall Resort State Park. Here you will have great views of Stonewall Jackson Lake, which is named after Confederate General Stonewall Jackson, who was born in Clarksburg (about 20 miles north of here) and raised in nearby Jackson’s Mill. From this spot we can observe some of the local geology of the area.
Lewis County is located near the southern extent of the Allegheny Plateau. The Allegheny Plateau region of the eastern United States stretches from the Mohawk Valley in New York State southward through parts of Pennsylvania, Ohio, Maryland, West Virginia and Virginia and extends for about 500 miles. The Allegheny Plateau was formed when sediments were deposited in a shallow inland sea over millions of years and were squeezed under millions of tons of pressure resulting in sandstone, silt, and shale. Siltstone and sandstone are both sedimentary rocks. Siltstone is mostly composed of silt and has a gray/red/brown color. Sandstone is composed of sand particles and can also be found in variety of colors including tan, brown, yellow, red, gray and white. Sandstone layers are highly resistant to weathering and erosion because of it has a high quartz content. Shale is another sedimentary rock and formed from consolidated mud or clay. The valley floor and lower slopes are underlain by Mississippian- and Devonian-age sandstones and siltstones of the Shenango through Oswayo Formations. These rocks are overlain by sandstones and conglomerates of the Pennsylvanian-age Pottsville Formation, which forms the upper slopes and ridges.
If you have driven on some of the backroads in the area, you might have noticed that while the area is very mountainous, all of the mountains seem to be roughly the same height and look alike. The Allegheny Plateau was lifted when the Appalachian Mountains formed, and over the course of millions of years, streams and rivers eroded into the plateau cutting numerous hollows and valleys into it, which is why the Allegheny Plateau is considered a dissection plateau. It is also worth mentioning that the region is rich in coal deposits, which can be found in 53 (out of 55) counties in West Virginia. 43 counties have reserves of minable coal and there are 30,000 direct jobs as a result of the coal industry. Coal also generates 99% of the electricity consumed in the state.
There are two two types of weathering processes, physical or chemical. Physical weathering breaks rocks apart without changing their chemical composition. For example fast moving water can cause rocks to collide with each other, breaking off small pieces. Another example is frost action. When water freezes it expands. When a small amount of water gets into cracks within the rock and then freezes, it gradually keeps expanding the crack within the rock wider and wider until it breaks off. Lastly there are plant roots. When plants grow in cracks within rocks, their roots can cause the crack to become larger and eventually break apart the rock. Chemical weathering in contrast breaks apart the rock by chemical reaction. Examples include oxidation, hydrolysis, or carbonation. Oxidation is kind of like rust, it can give a rock a bright red color, which we mostly see out west. Hydrolysis breaks down rocks by acid rain resulting in clay and soluble salts. Carbonation occurs when water is mixed with carbon dioxide to form carbonic acid, which can dissolve rocks such as limestone and form caves.
One of things around us that we might not think much of is soil. Soil is almost everywhere we look and plays an important role since it allows vegetation to grow and for us to build buildings upon. It includes disintegrated rock, humus, inorganic and organic materials. When a range of different forces (which we have mentioned earlier) act on the rocks, they break into smaller parts to form the soil. There are three main types of soil, sandy, clay, and silt. Sandy soil consists of small particles of weathered rock. It is not good for growing plants because it has almost no nutrients and does not hold water. Silt soil has particles smaller than sand (but bigger than clay). It holds water better than sand and is easily transported by moving currents and it is mainly found near rivers, lakes and other bodies of water. Lastly there is clay soil. The particles are tightly packed and water cannot penetrate it. We can also have combinations of the three (as shown in the image).
- Looking around, what evidence do you see that supports this region being a dissection plateau?
- Looking at the banks of the lake, describe the soil that you see. Using the chart as a guide, what type of soil does it appear to be? How do you think the surrounding geology influenced what you see?
- Do you see any vegetation in the water? What does this tell us about the physical properties of the soil?Proceed to either end of the boardwalk and away from the lake. Describe the characteristics of the soil. How is it different? Using the chart as a guide, what type of soil does it appear to be?
- Upload a photo taken from the boardwalk. You do not need to be in the photo, though it is strongly encouraged.