Shale Stone
Shale is a fine-grained rock of sedimentary nature that forms due to the compaction of silt and clay-sized minerals that we commonly deem as mud. An intrinsic feature of shale is its tendency to split into thin layers less than one centimeter in thickness. Shale is the most typically found sedimentary rock in nature.
The composition of shale is such that we can also term it as 'mudstones.' It is distinguished from other mudstones based on its fissility and lamination. Shale is an essential natural resource that comprises organic material which breaks down to form natural gas. Moreover, shale can be crushed and mixed with water to produce clays. Now that we have touched upon the basics of shale rock let us explore its many properties.
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Properties of Shale Rock
Let us try to answer the question – what is shale rock – in further detail by analyzing its characteristics.
Texture – The most distinguishable characteristic of shale is its varying fissility. On account of its natural construction, shale rock peels off into thin layers.
Composition – Shale comprises at least 30 percent clay and has varying quartz, feldspar, carbonates, iron oxides, and organic matter. Oil shale also contains kerogen, which is a mixture of hydrocarbons from dead plants and animals.
Color – The typical colors of shale varies depending upon their composition. Shale with a higher concentration of organic matter is grayish to black. Likewise, shale with a high ferrous content is red, brown, or purple in the shade. Lastly, shale that has more significant amounts of calcite is pale grey or yellow.
Having talked about the various properties of shale, let us move towards the topic of shale formation. There are multiple classifications of shale, which are divided based on the rock's mineral content. We have siliceous shale or silica, calcareous shale or calcite, limonitic shale, carbonaceous or bituminous shale, and phosphatic shale stone.
Shale Formations – A Crisp Summary
The formation of shale happens via a slow and gradual process known as compaction. The compaction from particles in quiet and calm waters such as rivers, lakes, deltas, or the ocean floor results in shale formation. The heavier particles sink and form limestone and sandstone, whereas the finer and lighter silt and clay particles remain suspended in water. In due course of time, the compressed sandstone and limestone become shale. We can usually observe shale as broadsheets that are several meters thick.
Now that we have deliberated upon the shale stone, let us turn towards shale gas and understand it in further detail.
Shale Gas – Things You Need To Know
Shale gas is a natural gas that is found trapped inside shale formations. Black organic shale stones are the source rock for many of the globe's most vital oil and natural gas sources. Black shales get their jet black color from tiny organic matter deposited with the mud that formed them millions of years ago. With the warming and burying of the mud, some organic material changed into oil and natural gas. It is noteworthy to remember that shale gas is a significant natural gas worldwide, especially in the global North. Studies show that in 2000, shale gas only accounted for 1 percent of the US natural gas production, and the proportion inflated to more than 20 percent in 2010. Experts predict that by 2035, 46 percent of the United State's oil and natural gas supply will emanate from shale gas. It is estimated that China has the world's largest reserves of shale and shale gas.
Shale Uses
There are several commercial uses of shale. It is a raw material in a myriad of ceramics industries to make bricks, tiles, and pottery. Crushing shale and heating it with limestone results in the creation of cement for the construction industry. Shale is also the most common source rock for hydrocarbons – petroleum and natural gas. About 95 percent of organic matter in sedimentary rocks is found in shales and other mudrocks.
In conclusion, we can understand the nitty-gritty of shale and shale gas. The contemporary relevance of shale stone is paramount.
FAQs on Shale
1. What is black and grey shale?
A shale stone that is black or grey in color is known as black and grey shale. It is essential to remember that black color in any sedimentary illustrates the presence of organic matter. The black to grayish color in shale stones are formed from sediments deposited in an oxygen-deficient ambiance. We must remember that organic debris in black shales makes them incredible candidates for oil and natural gas production. Grey shales have less amount of organic matter as compared to black shales.
2. What is shale density?
The density of solid shale is equal to 2675 kilograms per meter cube.
3. What are slate and schist, and how do they differ from shale?
The terms – slate, shale, and schist were interchangeably used till the middle of the 19th century, but things changed after that. If shale is subjected to intense heat and pressure, it can metamorphose into slate. Slate can, eventually, become schist through a similar metamorphosis process.
4. What are mudrocks?
Mudrocks are a category of fine-grained sedimentary rocks. Some of the common mudrocks include claystone, slate, shale, and siltstone. Mudrocks comprise 50 percent of all the sedimentary rocks in the geologic record and are widely deposited worldwide.
5. What are a few of the exciting facts about shale?
The various exciting facts of shale are
Shale is the most commonly found sedimentary rock. It accounts for 70 percent of the rock in the earth's crust.
Shale is a fine-grained rock of sedimentary types that are made from compacted mud and clay.
The defining feature of shale is its ability to peel off into layers.
The most typical types of shale are the black and grey shales.
There are several commercial uses of shale in the pottery, brick, and tile-making industry.
