What do black shales represent?
Black shales and seawater also represent significant reserves of uranium, although economic extraction of uranium from each is a challenge. Uranium in shales resides with organic matter.
What type of rock is black shale?
Black Shales are fine grained, generally organic carbon-rich sedimentary rocks that primarily consist of a mixture of clay minerals, quartz silt, organic particles (mostly planktonic algae and plant debris), and kerogen.
What is facies description?
In geology, a facies (/ˈfeɪʃiːz/ FAY-sheez; plural also facies) is a body of rock with specified characteristics, which can be any observable attribute of rocks (such as their overall appearance, composition, or condition of formation), and the changes that may occur in those attributes over a geographic area.
What is black shale the source of?
Black shales are source rocks for petroleum and natural gas, and thus are both geologically and economically important. Here, we review our recent progress in understanding of the surface ocean ecosystem during periods of carbonaceous sediment deposition, and the factors triggering black shale deposition.
Is gold found in black shale?
Black shales are favorable host rocks for many types of ore deposits (Grauch and Huyck, 1989, Starostin and Yapaskurt, 2007). Among them gold is very important, and many large and superlarge gold deposits are related to black shales.
What is blue shale?
‘Blue Shale’ from the Midway Shale formation is present in a pattern across Texas through Corsicana to Texarkana and stopping near Laredo. Jack Sinclair of TXI Industries has explained that the shale is mined and ground to 1″ to l/2″ range particles and then kiln fired.
Is black shale clastic?
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite. Shale is the most common sedimentary rock.
What are the types of sedimentary facies?
Sedimentary facies are either terrigenous, resulting from the accumulation of particles eroded from older rocks and transported to the depositional site; biogenic, representing accumulations of whole or fragmented shells and other hard parts of organisms; or chemical, representing inorganic precipitation of material …
What is facies variation?
A lateral or vertical variation in the lithologic or paleontologic characteristics of contemporaneous sedimentary deposits. It is caused by, or reflects, a change in the depositional environment.
Is there quartz in shale?
Shales characteristically consist of at least 30 percent clay minerals and substantial amounts of quartz. They also contain smaller quantities of carbonates, feldspars, iron oxides, fossils, and organic matter.
Can silver be found in shale?
The principal gold-bearing stratum is supposed to be the Benton group, including the Ostrea shales and the Blue Hill shales. It is stated that these rocks over practically the whole of the areas in which they occur contain more or less gold and silver, though the metals may be rather irregularly distributed.