Mergel is a rock that can contain many different components. Her appearance is very unpresentable. The dull color, the lack of a beautiful shine make the breed unattractive for decoration, decoration or collecting, but its other properties are very useful in construction.
Mineral Marl
The name "marl" comes from the German language. In another way it is called "ruhlyak" and "clay limestone." Mergel is very similar to slate, argellite, siltstone. Depending on the ratio of the main components and the composition of additional impurities, it has various properties and characteristics. So, more than twenty of its species are distinguished: gypsum, clay, chalky, calcareous, cement, freshwater and others.
Mergel is not a mineral. It is a rock, composed mainly of clay particles and calcium carbonate in any mineral forms. In most cases, it consists of a mixture of clays, dolomites and gypsum in various proportions, sometimes clay and silicates.
Depending on the mineral composition of the carbonates that make up the marl, it is divided into limestone, dolomite or gypsum-dolomite. According to the composition of impurities, it can be carbonaceous, sandy, siliceous, micaceous, etc.
Physical and chemical properties
The marl rock is painted in light shades. Usually it has a brown, reddish or white-yellow color. Black, dark gray and colorful shades are much less common. The structure of the rock is fine-grained or cryptocrystalline; in its structure, it can be homogeneous whole or layered.
Like limestone and chalk, marl reacts with hydrochloric acid. At the same time, a dark clay spot appears on its surface, which distinguishes it from other rocks. Mergel soaks well in water, acquiring the smell of clay. Wet slightly, it may stick a little to the tongue. In a large amount of liquid, it loses strength and dissolves in it, like chalk. However, this only happens when the clay content is high. If marl contains a lot of silicon or carbonate, then it is much worse affected by water.
In addition to the main components, a mineral may contain iron compounds, which give it a reddish tint. Common components of the rock are fractions of quartz, sand-silt particles, as well as fossilized remains of ancient plant and animal organisms.
All types of marl have different properties, which depend on the composition of the rock. The main characteristics by which they are compared and classified:
- Plastic.
- Density.
- Porosity.
- Humidity.
- The ability to swell.
- Consistency.
- The ability to compress.
Clay marl
The clay type of rock is usually loose and very unstable. It lends itself easily to cracking, breaking and weathering. It absorbs moisture well and soaks. Clay particles in such a rock can contain from 45 to 75%, the rest is carbonate and various impurities.
Chalky Marl
The fin-like breed is usually painted in light shades, has high friability, weak strength and density. It is easily rubbed and crumbles, a very soft touch. Mergel of this type contains up to 30% clay and about 30-90% calcite. In large quantities, it contains calcareous remains of the skeletons of organisms.
Flask
The flask is also called siliceous or fiery marl. This is a rock that is mainly composed of opal mineral. Its content can reach from 50% to 90%. Unlike marl, clayey and finely similar, flask is a fairly strong material. It has great porosity, is painted in gray shades and rings like stones when falling. It often includes particles of skeletons of ancient organisms, as well as fractions of spar, quartz, glauconite and clay.
Breed formation
Mergel is a sedimentary rock that takes billions of years to form. It is formed during the deposition of clay particles, mineral carbonate residues, as well as the abrasion of shells and external skeletons of marine inhabitants.
The rock lies in layers or in the form of monolithic stone blocks. It is not very stable and durable, relatively easy to transform under the influence of various climatic, geological and erosion processes.
Clay marl is formed on the seabed due to layering of bottom sediments. Due to this, they are more loose and unbound. Lime and stone rock species are more dense and solid. They are formed under the influence of the destructive forces of water, as well as pressing by layers that lie above.
Place of Birth
Fossil marl is widespread on the planet and is always accompanied by deposits of limestone and clay. The breed is mined in Belarus, Russia, Ukraine, various European countries, as well as on the American continent.
Rocks are formed in lagoons, at the bottom of the seas, saline and freshwater lakes. That is why it is found in places where water bodies were once located. The main quantity of marl in the international market is supplied by England, Greece and Turkey. Large mineral deposits are also found in Italy and the United States of America. In addition, the breed is mined in the Caucasus, in the Crimea, in the Amvrosievsky district of the Donetsk basin, in the Tatsinsky district of the Rostov region, in the Krymsk of the Krasnodar Territory, in the Beloretsky, Tulmensky, Inzersky districts of the Republic of Bashkortostan and other deposits.
Marl mining
For sale marl is prepared in the form of solid stones or in the form of large stone chips. Due to the prevalence of the material, its cost is not at all high. One cubic meter of marl costs about 7-10 dollars.
As a rule, the rock is mined in an open way using special machines for cutting stone. Marl quarries are huge horizontal stepped terraces, each ledge of which is 15-20 meters in height. Machines split several layers of rock, which are then loaded onto vehicles and transported for further processing.
To turn marl into crushed stone, rotary or jaw crushing machines are used. Most often it is turned into Portland cement, which is then used as a building material. To do this, the marl is ground in mills and burned in furnaces.
Where is it used?
The rock does not have any decorative value, and a wide range of applications, too. Nevertheless, people have known and used it since ancient times. So, in antiquity, marl served as fertilizer for soils. The soil saturated with it gets rid of excess acidity and absorbs moisture perfectly. On this foundation, herbs, grains and grapes grow remarkably, so this simple technology is used today.
In addition, marl is a common building material. Basically, it is not used independently, but as a component for cement mortars. In some countries, it is used as a brick for the construction of various structures. However, the material is not very durable and reliable; over time, it may slightly crumble or break off from the effects of wind and precipitation. Because of these features, tall houses are not built from it, but only buildings with a maximum of two floors are built.