Sedimentary Rocks

What are Sedimentary rocks?

Sedimentary rocks form over time and frequently exhibit strata that may be observed in cliffs. Igneous and metamorphic rocks are two other types of rocks. Sediments are made up of materials that sink to the ocean’s and lakes’ bottoms.

The processes that cause these particles to settle in situ are collectively known as sedimentation. Sediment comprises geological detritus (minerals) or biological detritus, and it forms the foundation of sedimentary rocks (organic matter). Weathering and erosion of existing rocks and the solidification of molten lava blobs ejected by volcanoes are responsible for the geological debris.

Many of the scenic landscapes of the desert southwest are created by these rocks, which frequently have distinct layering or bedding.

Types of sedimentary rocks on the basis of origin:

1. Common sedimentary rocks-Sandstone, limestone, and shale are all common sedimentary rocks. Sediments carried by rivers and deposited in lakes and oceans are the most common sources of these rocks. When sediments are buried, they lose water and get cemented, resulting in the rock formation.
2. Clastic sedimentary rocks-  Clastic sedimentary rocks are made up of cemented together rock pieces called clasts. Individual grains of quartz, feldspar, clay minerals or mica are typically found as clasts. Any mineral, however, could be present. Clasts can also be lithic pieces made up of many minerals.

  3.-Conglomerates and breccias

Breccias are made up of jagged gravel, whereas conglomerates are mostly made up of rounded gravel. The conglomerate is a clastic sedimentary rock made up primarily of rounded to subangular gravel-sized clasts.

4. biochemical sedimentary rocks-When organisms utilise materials dissolved in air or water to develop their tissue, biochemical sedimentary rocks form.
5. Chemical sedimentary rocks- Mineral components in solution become supersaturated and inorganically precipitate, resulting in the chemical sedimentary rock formation.

Types of sedimentary rocks on the basis of formation-

• Chalk-Chalk is a type of limestone made primarily of calcium carbonate and generated from the shells of foraminifera. The colour of chalk is usually white or light grey.

• Caliche is a shallow layer of soil or silt in which mineral substance has precipitated in the interstitial spaces of the particles, cementing them together.
• Chert is a sedimentary rock made up of microcrystalline. It can be found in the form of nodules,  masses, and layered deposits.
• Coal is an organic sedimentary rock formed by the collection and preservation of plant components. Coal is used for a variety of purposes, the most important of which is the creation of power.
• Diatomite is a light-coloured sedimentary rock; It’s a porous rock with small grains and low specific gravity. It can be used as a filter media, an absorbent, and a light filler for rubber, paint, and plastics.
• Coquina is a sedimentary rock that is almost entirely made up of sand-sized fossils. Coquina is devoid of silt or clay-sized particles, and its fossil fragments are only faintly bonded together.
• Dolomite-Limestone and dolomite are two rocks that are quite similar. It is also known as dolostone because it has similar colour ranges of white to grey and white to light brown.
• Flint is a chemical or biological sedimentary rock with a conchoidal fracture. In sedimentary rocks like chalk and marine limestones, flint commonly develops as nodules.

Sandstone, shale, oil shale, rock salt, iron ore, and limestone are some more types of sedimentary rocks.

Uses of sedimentary rocks

1- Building construction- sandstone and limestone are used for the construction of buildings.

2- Structural wall construction-For the construction of structural walls, both sandstone and limestone are acceptable. Sandstone, on the other hand, should be approached with caution because it may be too porous and weak for load-bearing constructions. Production of Concrete

3- Concrete production-Sedimentary rock is a pressure-resistant aggregate used in concrete production.Construction of Pavements and Roads

4-Pavement and road stones are made of sandstone and limestone. Road construction employs shale as an aggregate. The roadbed of a highway is made of sedimentary rocks.

5-Manufacturers of bricks and tiles-Shale is a component of brick and tile making materials. Production of Cement.

6- Architectural and monumental construction- Portland is a type of sedimentary stone that can be used in monumental construction.

7- Building interior decoration-

Marble is used in making the upper part of tables and interior decoration products.

8-Filler in paints-Shale is a sedimentary rock that can be used as a filler in a variety of paintings.

9-Plaster and Sheetrock.

Sheetrock and plaster contain a lot of gypsum. Gypsum is a kind of sedimentary rock.

10-Wallboard 

Gypsum is pounded into a powder and used to make wallboards. 

11-Others-

Earthen dams, railroad ballast, canals, and rockfill are all constructed with sedimentary rocks.

Conclusion

Sedimentary rocks are significant because they preserve evidence of the deposition processes at the surface. Higher energy depositional settings are indicated by larger particles. During lithification, sedimentary formations emerge. Geologists can use cross-bedding to establish ancient wind directions.