How can we identify sedimentary rocks?
If the sediment is buried deeply, it becomes compacted and cemented, forming sedimentary rock. Clastic sedimentary rocks may have particles ranging in size from microscopic clay to huge boulders. Their names are based on their clast or grain size. The smallest grains are called clay, then silt, then sand.
What are sedimentary rocks main features?
Sedimentary structures include features like bedding, ripple marks, fossil tracks and trails, and mud cracks. They conventionally are subdivided into categories based on mode of genesis. Structures that are produced at the same time as the sedimentary rock in which they occur are called primary sedimentary structures.
What are two key minerals found in clastic sedimentary rocks?
Thus the most important minerals in clastic sedimentary rocks are quartz, potassium feldspar (microcline and orthoclase), plagioclase, clays, and oxides/hydroxy-oxides (hematite, limonite, goethite).
Why are crystals absent in sedimentary rocks?
Sedimentary rocks are formed due to the transportation and deposition of sediments in river beds. Crystals require very high temperatures to form but there is no thermal process in sedimentary rock formation. This is why Sedimentary rocks don’t form crystals while igneous rocks form crystals.
What are crystalline sedimentary rocks?
Sedimentary rocks can also be crystalline, such as the crystalline limestones precipitated directly from solution; the term is not generally applied to the clastic sediments, even though they are formed largely from the accumulation of crystalline materials.
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.
What can Shale be used for?
Shale has many commercial uses. It is a source material in the ceramics industry to make brick, tile, and pottery. Shale used to make pottery and building materials requires little processing besides crushing and mixing with water. Shale is crushed and heated with limestone to make cement for the construction industry.