Coal

Cementing agent such as calcites and silica hold the individual grains together. The principal resource of material to produce cement for construction use, limestone is a sedimentary rock. Both the cementing agent and the way the rock was deposited influence a sedimentary rock’s strength. Clastic rocks are sedimentary rocks that are made from other, preexisting rocks that were eroded into sediment, transported, deposited, and lithified but chemical sedimentary rocks are different in that they form by precipitation of ions and minerals out of a solution most commonly seawater. Also, coal it is an important fossil fuel source around the world.

Coal

Coal is a sedimentary rock termed organic, because its main component is plant material. Coal is formed from vegetation that previously existed in swampy or marshy waterlogged soil which prevented their full decay after death. Coal is a sedimentary rock, black, and rich in carbon, used as a fossil fuel. One type of coal is limestone, it is usually of organic origin, having been formed from accumulated shell, coral and other marine organisms. As their remains piled up and covered by more and more deposits, they gradually underwent compaction and cementation. Coals can be also found in Pennsylvania, provinces like High Plateau, Pittsburgh Low Plateau, Allegheny Mountain, Glaciated High Plateau, Appalachian Mountain, Susquehanna Lowland, Blue Mountain, Great Valley, and Piedmont Lowland. (“Map 13, Physiographic Province of Pennsylvania”)

Chemical Sedimentary Rock

What happens when you allow a glass of saltwater to evaporate? Eventually the water disappears and a layer of salt accumulates on the bottom of the glass. A similar process occurs in nature when chemical sedimentary rocks are formed. During chemical weathering, minerals can be dissolved and carried into lakes and oceans. As water evaporates from the lakes and oceans, the dissolved minerals are left behind. In arid regions, high evaporation rates can increase the concentration of dissolved minerals in bodies of water. Chemical sedimentary rock are formed by chemical deposition of materials that have been in solution during its transport. Examples: gypsum, anhydrie and limestone. And organic sedimentary rocks are formed from the precipitation of certain chemical compounds in aqueous solutions or by accumulation of organic substances. A very common type is the limestone, formed mostly by the remains of organisms such as corals, algae, etc.

Florida Sinkholes

Sinks, sinking into the ground surface, can also be hidden under the surface. They are very common in Florida. They may be deep or shallow, small or large, but are always the same geological process. Much Florida surface consist of what is known as “Karst “. This is an area created by water dissolving the limestone bedrock and is characterized by sinkholes, cave systems, and springs. Sinkholes occur as a natural process of erosion of the limestone.

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