Limestone - sedimentary , clastic rock of organic, less often chemogenic origin, consisting mainly of calcium carbonate (CaCO 3 ) in the form of calcite crystals of various sizes.
Limestone, consisting mainly of shells of marine animals and their debris, is called a shell rock . In addition, there are nummulite , bryozoan and marble-like limestones - massive - layered and thin-layered . In metamorphism, limestone recrystallizes and forms marble .
Calcium carbonate, which is part of the limestone, is able to slowly dissolve in water, as well as decompose into carbon dioxide and related bases . The first process is the most important factor in the formation of karst , the second, occurring at great depths under the influence of the deep heat of the Earth, provides a source of gas for mineral waters .
Content
Deposits
Limestone is a widespread sedimentary rock formed with the participation of living organisms in marine basins. This is a monomineral rock consisting of calcite with impurities. The name of the limestone variety reflects the presence in it of the remains of rock-forming organisms, the area of distribution, structure (for example, oolitic limestones), impurities (glandular), the nature of occurrence (limestone), geological age (Triassic).
Of the limestones, whole mountain ranges are composed in the Alps , in the Crimea, and is also widespread in other places. Limestone has no shine , it is usually light gray, but can be white or dark, almost black; bluish, yellowish or pink, depending on the composition of the impurities. The limestone contains the remains of ancient animals.
In Russia, limestones are common in the central regions of the European part, and are also common in the Caucasus, the Urals and Siberia [1] .
The Russian platform deposits are widely known, the limestones of which have traditionally been used for the construction and exterior decoration of buildings. Today, the raw material base of these limestones, including the white limestones of the Shcharovka horizon, is very limited [2] .
One of the most promising limestone deposits considered to be the Zhdanovskoye field discovered in 2015 ( Orenburg Region ), where at present [ when? ] There is industrial mining of Sarmat limestone [3] . The field supplies limestone with high quality indicators, has large reserves and shallow bedding .
Application
Limestone is widely used as a building material, fine-grained varieties are used to create sculptures .
Limestone firing gives quicklime - an ancient cementitious material, so far used in construction [4] . One of the main building materials derived from limestone is limestone crushed stone , which is widely used in road construction and in the production of concrete . In metallurgy, limestone is used as a flux . Limestone is used in the chemical and food industries: in the production of soda, mineral fertilizers, glass, sugar, paper.
Shell Rock
Shell rock (shell rock, cockleshell) is a building material of natural origin, known since ancient times and popular in the southern regions of Russia, as well as in coastal regions of Ukraine and Kazakhstan.
Shell rock is used:
- in housing construction: masonry of external walls and construction of internal partitions;
- at household facilities: construction of basements, garages, fences, etc .;
- in landscape design: retaining walls, fountains, grottoes;
- during facing works: in the form of a tile with its obligatory preliminary hydrophobization and polishing.
The most common brands in terms of strength: M35, M25, M15.
A block of standard geometric dimensions 380 × 180 × 180 mm with a compressive strength of up to 15 kg / cm 2 is considered light. The walls of it withstand the load during a one-story building, the construction of garages and utility facilities.
It is preferable to erect two-story houses from stone of grade M 25. And only the most wear-resistant and durable blocks (M 35) are used for the construction of wall structures of basements and basement parts of foundations.
Notes
- ↑ Limestone deposits . Encyclopedia of the Krasnoyarsk Territory .
- ↑ Zvyagintsev L.I. White-stone Russia. - Moscow: "The World of the Mountain Book", 2008. - 306 p.
- ↑ Suprun E.V. Limestone "Sarmat" - a unique natural building material // "Stone and Business": Journal. - 2016. - March ( No. 3 ).
- ↑ Krupsky A.K. , Mendeleev D.I. Lime, in technology // Encyclopedic Dictionary of Brockhaus and Efron : in 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.
Links
- Limestone - an article in the encyclopedia Krugosvet.
- Limestone is a rock formation. Description, photos, deposits.
- Shell rock: eco-friendly material for building a house