For centuries, the main building material was rock.Types of rock people selected according to their characteristics, physical properties, strength, density, amortization, and so on.. Because manually process the stone is not so simple, in ancient times from it erected only the most important objects, such as palaces, defensivebuildings, cultural monuments.It is from these natural materials, built the legendary Egyptian pyramids, the Great Wall of China, Aztec pyramid, the Taj Mahal and other famous buildings that are wonders of the world.
Feature
different stones are not a random accumulation of minerals, and their legitimate association.Determination of rocks can be summarized as follows: it is a naturally occurring mineral aggregates with a constant structure and composition.For the first time this term was used by Russian chemist and mineralogist VM Severgin in 1798.Depending on the strength, decorative, density, porosity, frost resistance and other characteristics, the use of different minerals found.Mainly used in construction work rocks.
classification of rocks
Depending on the method of their formation, all minerals can be divided into three large groups.Scientists have isolated sedimentary, igneous and metamorphic rocks, in a class attribute type mantle.This is a natural association of various substances and minerals that make up a significant portion of the earth's crust.
For centuries, volcanic emissions caked and accumulated, the magma cools and solidifies.Thus formed igneous rocks occurring in the upper mantle and the crust at different depths.
Fragments of different origin form sedimentary type.Specialists Through analysis, determine the type of environment in which the materials were deposited, especially their origin, type of agents, transfer them, and so on. D.
metamorphic rocks occur at change of magmatic and sedimentary types in the earth's crust.Such rocks have a unique chemical composition, but it is based on the parent mineral from which they were formed.All metamorphic processes mostly occur in the bowels of the earth's crust.
There mantle rocks that were originally magmatic origin, but then have undergone significant changes in the mantle.
magmatic rocks
Researchers distinguish two major types of magmatism effusive and intrusive.They differ in the place of solidification of magma, and the nature of its movement.In addition to these two, there are wedges and hypabyssal igneous rocks that are borderline type.They give dikes and veins, forming in the cracks of other stones during the solidification of magma.
Intrusive or plutonic rocks undergo a long process of education, which can last more than a millennium.They may contain crystals of an enormous size as magma cools very slowly at a great depth.Although plutonic rocks originally located in the very depths of the earth's crust, when it picked up the weathering and they often transform into mountains.A striking example is the mountain Shpitskoppe in Namibia.The main minerals of this type are granite, labradorite, syenite, gabbro.
effusive igneous rocks (volcanic) type are formed by a volcanic eruption, that is when the magma comes to the earth's surface.They do not create large crystals due to rapid cooling.A striking example of this type of rocks are rhyolites and basalts.Of those in ancient times often made various sculptures and monuments.
sedimentary clastic minerals
, chemogenic and Organogenic - these are the main types of sedimentary rocks.They vary depending on the process origin and formed on the surface.Clastic type is formed due to caking and cementing of separate fragments of different rocks.A striking example of such minerals can serve as sandstones and conglomerates.In Barcelona, there is an array of Montserrat, here it is just a conglomerate, because it consists of bonded cement limestone boulders.
beds of rock types are formed from mineral particles, precipitation in water.It is based on the classification of the mineral composition of rocks occurs.The most common representative of the beds of limestone is.For example, Australia has a desert pinnacles formed just because of this breed.Organogenic type much like coal, because he, too, is formed due to the caking of the remains of animals and plants.All sediments characterized fracture, porosity and solubility in water.
metamorphic minerals
classes of rocks are often quite arbitrary.It may belong to the type of metamorphic minerals such as sedimentary and magmatic origin.They have varying degrees of intensity of the processes of transformation.If it is low, the metamorphism to determine the parent rock, but with a high degree make such impossible.Such minerals change their composition and texture.For this reason, metamorphic rocks are divided into schistose and neslantsevatye, and depending on the conditions of formation divided into three groups: Regional, hydrothermal and contact metamorphism.
Sometimes it happens that the huge boulders of rocks exposed to the outside, such as low or high temperatures, pressure.A striking example can serve as gneisses.These are minerals can be considered regional.Hydrothermal metamorphism occurs with the participation of thermal sources.Mineral-rich ions in contact with a hot liquid, wading through fissures of the mountains, and the chemical reaction that alters the composition of the rocks.As an example, quartzite, often formed by limestone.There is contact metamorphism.In this case, the rock exposure to chemical and temperature rise intrusive igneous mass.
properties of rocks
are several properties of minerals, and they are all important to varying degrees.If they are used as a cladding material, the focus is primarily on their aesthetic appeal.In some cases, decorative stones is very important, steals his drawing, color.From the index depends on the density of how much weight the rock.Types of rocks are light and heavy.At first a density - up to 2200 kg / m3, and the second - more than 2200 kg / m3.If the stone is selected for construction of the structure, then there have to take into account the weight of what it is denser, the harder it will design.This option depends on the composition of the rock porosity.
One of the most important properties of the stone (especially when it comes to construction) is a strength.It affects the durability of the material.The stronger the mineral, the longer it will retain its original appearance.In this regard, all the stones are divided into three groups: low, medium and strong strength.It all depends on the composition of rocks, namely the hardness of minerals.For durable stones include gabbro, granite, quartzite, to the middle - limestone, marble, travertine, tuff have low strength, loose limestone.
Different types of rocks have different porosity.From this it depends on the characteristics of acid and salt resistance, water absorption of stone.Porosity is necessary to pay attention to if certain species chosen as a lining.This figure defines the durability of the material, its polishability, durability, decorativeness, thermal conductivity, machinability and the like. D. The higher the porosity, the less the weight of the stone, it is better handled, but at the same time reducing its volume, the strength deteriorates polishability.
water absorption breed is also very important.On it depends frost, acid and salt resistance of the material.Water trapped in the pores during freezing increases in volume creates a pressure, because of which eventually cracks.The same thing happens with the salt solutions that promote the growth of crystals, creating additional pressure.If the porosity of the mineral is low, it cracks in some cases it may even split.The porous stone pressure is evenly distributed, and no cracks do not appear.
change processes of rocks is largely influenced by their acid resistance.Acids can transform and even destroy some of the minerals.Therefore, when choosing a stone for the construction of buildings should take into account this fact.For example, hydrochloric acid poses a serious threat to the marble, dolomite, travertine.But limestone and granite are characterized by excellent resistance to acids, so has survived until today so many iconic designs of these materials.
conversion processes
Huge boulders, majestic mountains give the impression of mighty giants, the timeless time and a variety of factors outside.They seem to retain the original appearance over the centuries and millennia, but it is not so.Over time, undergo any significant changes rocks.Classification of rocks to determine how long the minerals retain their original appearance, that it has the greatest impact on them.
stone composition changes over a long period.The transformation of rocks may be of natural or man-made.The condition of the stones is affected by factors such as melted or ground water, rain, wind, sun, high and low temperatures.Destruction of rocks natural way is very slow, but it can not be stopped.The rain and wind wash away and erode both upper and underground landscapes.Gradually they change not only the shape but also the composition of minerals.
anthropogenic processes associated with human activities.Destruction of rocks can be carried out using the technique.For example, repeatedly construction crews were clearing the territory for the construction of facilities, and the cleaning of the mountain ranges.Of course, this activity destroys the natural landscape, it has a negative impact.Damaged rocks give a crack, because of this collapse occurs, collapses.Man is much faster could change the face of mineral deposits, rather than natural factors.
So everything Highlands over time change their appearance.The speed of their transformation depends largely on the external conditions, rock composition, strength, degree and duration of exposure.In the conversion process also affects the climate area in which the stones are located.
cycle rocks
geological processes of formation of igneous, sedimentary and metamorphic minerals are locked in a cycle.It begins with the fact that the magma pours out gradually cools and hardens, thus formed igneous rocks.Types rocks change once it is on the earth's surface.Wind, water, temperature extremes form the sedimentary type of minerals.The stones are broken up, weathered, moved from place to place, stopping in sedimentary basins.It was there that fragments of rock are completing their way become compressed and converted into the type of sedimentary minerals.Over time, the mountains sink to great depths, exposing the tectonic processes.All this leads to the formation of metamorphic rocks.At high temperatures and strong pressure minerals melt, turning into magma.Over time, it hardens to form igneous rocks, and the process of stone formation begins anew.
Petrology and petrography
both the micro- and macro-level studies are minerals.In the first case study only small particles of certain species, their transparent and translucent saw cut.This makes it possible to establish the characteristics and properties of minerals.In the second case, scientists consider all the rocks together, because they form a specific element of the earth's crust.The researchers can not determine the history, features and approximate date of their formation.
origin of rocks studied two disciplines: Petrology and petrography.The first explores the science of chemical and mineralogical composition of stones, the conditions of their occurrence, texture and structure.Petrology also determines the geological formations that make up the bulk of the Earth's crust.Petrography is engaged in the classification and description of different breeds, is more descriptive science.It examines some examples of rocks, their structure and composition.Petrographers work with transparent and translucent slices under a microscope examine the properties of their components.Also, scientists can work with samples of rocks of impressive dimensions.
There are several levels of minerals.First, scientists are engaged in drawing up geological maps, then held the field, petrographic and geochemical surveys.All of them complement each other and allow a complete picture.Field studies allow us to determine the structural features, the position of minerals, to establish the approximate time frame of their occurrence.Petrographic works define what are the rocks of origin, what is the percentage of minerals in them.
more complicated science is petrology.The need for special and deeper research is the result of the accumulation of a vast store of knowledge.By the rocks are different types of minerals, which correspond to sedimentary, igneous and metamorphic type.And each of them is subject to certain branches of study mentioned discipline.Thus, the science of sedimentary minerals are interested in the texture and composition of salt, limestone, sandstone, conglomerate and other sedimentary rocks.Igneous Petrology regards minerals crystallized from molten magma.Metamorphic science studies marble, schist, gneiss and other rocks formed during the transformation.
Among other things, the scientists are also involved in geochemical research.They give an overview of the chemical composition of the rocks, her age, place of origin, mineral phases, temperature and pressure at which it was formed.
most common rocks
On our planet, there is a huge amount of a variety of mineral deposits.Most of these people have found practical application.Some breeds are more popular, some less.Let's talk about the stones, often used by man.
Granites
Perhaps this is the most common stone composed of quartz, feldspar and mica.Granite has a granular crystalline structure, divided into three categories: small, medium and coarse.Stone has a variety of shades, considered the most rare blue-green, light gray and burgundy.Granite perfectly amenable to polishing some of its variants is subjected to heat treatment.This is done to create a more decorative effect.Operating properties and mechanical properties of granite are estimated very high, therefore the stone used for facade structures, embankments, the construction of basement structures.The stone is used to create sculptures.
Sandstones
another popular rock formation.Types of rocks depend on the method of education.Sandstones are sedimentary type, because it consists of cemented sand.In nature, there are stones in different colors: green, yellow, gray, red, brown.For decorative purposes are most commonly used fine-grained brown, red and green sandstone.Basically, they go to the liner buildings.
Marble
belongs to the granular-crystalline rocks, it was the result of the impact on the dolomite and limestone of high temperature and pressure.Marble has a high decorative properties, it is easy to work.Thus, grinding minimizes the clarity and brightness, polishing, on the contrary, strengthens the drawing, shearing brightens the background.Stone is a colored, gray and white.
Slate
Rock formed due to heavy clay seal, recrystallized under strong pressure sided.
