Formation of Sedimentary Rocks
Sedimentary rocks are formed from igneous rocks which have been subjected to weathering causing them to become minuscule granules such as sand. These granules are swept into rivers and deposited in sediment banks. Slowly, over millions of years, these sedimentary rocks are compressed and subjected to extreme heat and pressure under many layers of mud. The compression forces the water out from between the particles and causes them to chemically interact and bond with each other forming rocks. These sedimentary rocks have different chemical compositions depending on the minerals that form them consequently there are many different varieties of rock, although they share some similar characteristics in their structure.
Structure of Sedimentary Rocks
Sedimentary rocks are formed through compression of rock granules, therefore no crystals are present in their structure. Crystallization is not involved in their formation, the granules interact and bond due to the heat and pressure applied. The compression also causes the rocks to develop foliation or layers within themselves which would be formed of different types of mineral and which would be definite. The compression causes the minerals to become arranged into layers which are present in every single variety of sedimentary rock, whatever their chemical composition.
How do Sedimentary Rocks Differ from Other Rocks
Sedimentary rocks are the only rocks that do not have crystallization to some degree involved in their formation and the only ones that are not exposed to magma. This means that they have very different characteristics to igneous and metamorphic rocks. They are also the only ones which are formed of minuscule granules of rocks compressed and arranged into layers according to mineral meaning that they are totally and absolutely different from the other types of rock
Examples of Sedimentary Rocks
Sandstone: Sandstone is the basic sedimentary rock, formed from grains of sand that have been compressed under layers of mud until the particles bond forming a rock. Sandstone is not particularly hard but is used for some construction purpose. It is a brownish rock with clear layers and the individual granules of sand are sometimes visible. Sandstone is present in many cliffs across the world.
Limestone: Limestone is similar to sandstone, but has a chemical composition of calcium carbonate and is formed from the skeletons of tiny marine creatures. It is alkaline and is used as a pH regulator for agriculture as well as other purposes. It occurs naturally in many cliffs and also underground. Limestone is a lightly coloured foliated rock
Chalk: Chalk is a white sedimentary rock which is very similar to limestone. It contains calcium as well. It is soft and porous, although it occurs naturally in cliffs like the famous “White Cliffs of Dover” it is not appropriate for major construction projects but is mainly used for writing on blackboards etc.
Arkose: Arkose is a reddish sedimentary rock that is similar to sandstone but contains a higher concentration of the mineral feldspar. It also occurs naturally in rock formation and is used for forming corn millstones.
Sedimentary rocks are formed from igneous rocks which have been subjected to weathering causing them to become minuscule granules such as sand. These granules are swept into rivers and deposited in sediment banks. Slowly, over millions of years, these sedimentary rocks are compressed and subjected to extreme heat and pressure under many layers of mud. The compression forces the water out from between the particles and causes them to chemically interact and bond with each other forming rocks. These sedimentary rocks have different chemical compositions depending on the minerals that form them consequently there are many different varieties of rock, although they share some similar characteristics in their structure.
Structure of Sedimentary Rocks
Sedimentary rocks are formed through compression of rock granules, therefore no crystals are present in their structure. Crystallization is not involved in their formation, the granules interact and bond due to the heat and pressure applied. The compression also causes the rocks to develop foliation or layers within themselves which would be formed of different types of mineral and which would be definite. The compression causes the minerals to become arranged into layers which are present in every single variety of sedimentary rock, whatever their chemical composition.
How do Sedimentary Rocks Differ from Other Rocks
Sedimentary rocks are the only rocks that do not have crystallization to some degree involved in their formation and the only ones that are not exposed to magma. This means that they have very different characteristics to igneous and metamorphic rocks. They are also the only ones which are formed of minuscule granules of rocks compressed and arranged into layers according to mineral meaning that they are totally and absolutely different from the other types of rock
Examples of Sedimentary Rocks
Sandstone: Sandstone is the basic sedimentary rock, formed from grains of sand that have been compressed under layers of mud until the particles bond forming a rock. Sandstone is not particularly hard but is used for some construction purpose. It is a brownish rock with clear layers and the individual granules of sand are sometimes visible. Sandstone is present in many cliffs across the world.
Limestone: Limestone is similar to sandstone, but has a chemical composition of calcium carbonate and is formed from the skeletons of tiny marine creatures. It is alkaline and is used as a pH regulator for agriculture as well as other purposes. It occurs naturally in many cliffs and also underground. Limestone is a lightly coloured foliated rock
Chalk: Chalk is a white sedimentary rock which is very similar to limestone. It contains calcium as well. It is soft and porous, although it occurs naturally in cliffs like the famous “White Cliffs of Dover” it is not appropriate for major construction projects but is mainly used for writing on blackboards etc.
Arkose: Arkose is a reddish sedimentary rock that is similar to sandstone but contains a higher concentration of the mineral feldspar. It also occurs naturally in rock formation and is used for forming corn millstones.