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Shale is a geological rock formation rich in clay, typically derived from fine sediments, deposited in fairly quiet environments at the bottom of seas or lakes, having then been buried over the course of millions of years.
What causes shale to form?
Shale forms when layers of silt and mud collect and lithify (turn into rock). Specifically, lithified mud becomes stone and shale is thus known as “mudstone”. The Barnett Shale, Marcellus Shale, Haynesville Shale, and Fayetteville Shale are large deposits of shale with natural gas.
Is shale a mineral or rock?
Shale is the most abundant of all sedimentary rocks. It is composed primarily of soft clay minerals, but may include variable amounts of organic matter, calcareous material, and quartz grains. Shale may be any color, but is generally greenish gray to grayish black.
Where is black shale found?
Most black shales are found in marine sediments (Potter et al., 1980), but they can also form prominent deposits in lacustrine successions (Bohacs et al., 2000). Their black color is due to two constituents: (1) the contained organic matter, and (2) finely disseminated pyrite.
Is shale good to build on?
Rock. Solid rock, such as crystalline bedrock, bears the most weight of any type of soil, making it one building option. However, some types of sedimentary rock, such as shale, are not always a safe option on which to build. In time, sedimentary rock can break apart, causing the ground to shift beneath your structure.
Is shale easy to dig?
From a drillers perspective – shale is generally defined as deposited layers of clay that has been compressed & solidified clay formed in layers. It’s generally a soft & easily drilled rock that has a tendency to blow out under high air/water pressure. Soit shouldn’t be a problem with a decent machine on site.
Is shale a Bioclastic?
Silt is smaller than sand but larger than clay. Shale has the smallest grain size. Shale is made mostly of clay-sized particles and hardened mud.Clastic Sedimentary Rocks. Rock Sediment Size Other Features Breccia Large Angular Sandstone Sand-sized Siltstone Silt-sized, smaller than sand Shale Clay-sized, smallest.
Can gold be found in shale?
A shale bedrock has all kinds of crevices in it and erodes quickly, you can find gold In it but you have to break open a lot of bedrock to find the small pieces scattered about. shiner than others. That is because they are very hard. When these dense heavy rocks drop, the gold usually drops with them.
What are the disadvantages of using oil shale?
Another environmental disadvantage to extracting shale oil is the enormous amounts of freshwater required. Water is necessary for drilling, mining, refining, and generating power. Mining can also contaminate groundwater. During in situ processing, toxic byproducts are left underground.
Does shale break easily?
Shale is a hardened, compacted clay or silty clay that commonly breaks along bedding planes some of which are no thicker than paper. The best exposures are found beneath ledges of harder more resistant rocks such as limestone and sandstones. Most shales are soft enough to be cut with a knife and can be very brittle.
What is shale good for?
Shale is commercially important. It is used to make brick, pottery, tile, and Portland cement. Natural gas and petroleum may be extracted from oil shale.
What does Black shale indicate?
Black shale results from the presence of greater than one percent carbonaceous material and indicates a reducing environment. Pale blue to blue-green shales typically are rich in carbonate minerals. Clays are the major constituent of shales and other mudrocks.
What is black shale made of?
Black shale, also called Carboniferous Shale, variety of shale that contains abundant organic matter, pyrite, and sometimes carbonate nodules or layers and, in some locations, concentrations of copper, nickel, uranium, and vanadium.
Is shale detrital or chemical?
Sedimentary rocks Detrital Clastic texture (particle size) Sediment name Rock name Medium (1/16 – 2 mm) Sand Sandstone Fine ( 1/256 to 1/16) Silt Siltstone Very fine (<1/256 mm) Clay Shale or mudstone.
Is shale hard to excavate?
Shale is quite strong and also hyper-compressed, which means it’s extremely difficult to remove the oil and gas from the tiny pores in the shale itself.
What rock is gold found in?
Gold is most often found in quartz rock. When quartz is found in gold bearings areas, it is possible that gold will be found as well. Quartz may be found as small stones in river beds or in large seams in hillsides.
How do you identify black shale?
Black shales are dark-colored, usually thinly laminated mudstones containing appreciable organic matter (>0.5 wt% C), authigenic iron sulfides and, silt- and clay-sized detrital particles that in most cases have been accumulated under anoxic bottom water and/or bottom sediment conditions in marine or continental
Where is shale most commonly found?
Shales are often found with layers of sandstone or limestone. They typically form in environments where muds, silts, and other sediments were deposited by gentle transporting currents and became compacted, as, for example, the deep-ocean floor, basins of shallow seas, river floodplains, and playas.
Is shale oil better than crude oil?
Shale oil is a substitute for conventional crude oil; however, extracting shale oil is more costly than the production of conventional crude oil both financially and in terms of its environmental impact. Deposits of oil shale occur around the world, including major deposits in the United States.
Does Black Sand mean gold?
Black sands (mostly iron) can be and usually is an indicator of gold, but not always. Rule of thumb is you will generally find black sand with gold, but not always gold with black sand. However if you are finding gold and getting black sands with it, it would be worthwhile to try some and see what happens.
How long does shale take to form?
Shale formations are a worldwide occurrence (see Chapter 2). Shale is a geological rock formation rich in clay, typically derived from fine sediments, deposited in fairly quiet environments at the bottom of seas or lakes, having then been buried over the course of millions of years.
