Rock is one of the materials that make up the crustearthlithosphereThe main components of.Among them,feldsparyesCrustThe most important rock forming component in the[2]，quartzIt is the second most abundant ore.
The rocks are classified according to their genesis, structure and chemical composition. Most rocks containsilicon dioxide(SiO2), and 74.3% of the crustal composition is the latter.The content of silicon in rock is one of the important factors determining rock properties[3]。
Rock is an important source of early human toolshuman beingsevolutionIs of great significance.Therefore, the firstcivilizationThe period is calledStone Age。Rock has always beenhuman beingsImportant materials and tools for life and production.
In 2023, "plastic rock" will be discovered for the first time in the freshwater system[4]。
[Rock] Consisting of one or more than two mineralsconsolidationOr unconsolidatedAggregateSome of them are biogenic (such as coal) and exist in large quantities in nature, forming a large part of the crust.[1]
Citation explanation
1. Tall stones;Large stones.
Historical Records·Gao ZuThe Chronicle: "The Emperor Gaozu suspected himself, disappeared, and hid among the rocks of Mount Mangdang."
Southern Dynasty LiangJiang Yan《Wang Jianping wrote》"Above it lies hidden among the four chapters and lies under the rock."
clearChen Kangqi《Lang Qian's Notes》Volume 3: "(Suzhou Canglang Pavilion): exquisite rocks, water treesKiyomi Therefore, it is the top scenic spot in the city. "
Yang Mo《Song of Youth》The first chapter three: "Early the next morning, she was awakened by the sound of the waves beating against the rocks."
Out of Poems·Xiaoya·Festival of South Mountain: "Festival of South Mountain, Weishi rock. He is an outstanding teacher, and the people have their own vision."
Song DynastyZeng Gong"Revelation with Han Shizhong in Beijing": "It is better to avoid the trouble and return to the foreign service after a long time of drowning. It is better to look at Yan Shi and return to the foreign service after a long time of drowning."
Song DynastySu ShunqinThe poem "Wen Jing Yin, Fan Xiwen and other relegated officials" reads: "Great talk about rocking rocks, dangerous talk about picking diadem. The pale yellow leaves the capital and is exiled to Nanzhou."
Rocks are naturally produced minerals with stable appearance orGlassAggregates are combined in a certain way.Is to form the crust and uppermantleThe material basis of.Divided intoMagmatic rock、sedimentary rockandMetamorphic rock。Among them,Magmatic rockIt is caused by high temperature molten magmaSurfaceOr undergroundcondensationThe rock formed is also calledigneous rock。Magmatic rocks erupting from the surface are called extrusive rocks or volcanic rocks, and those condensing underground are called intrusive rocks.Sedimentary rock is formed byWeathering, biological action andVolcanismThe products ofdepositionRock formed by consolidation with diagenesis;Metamorphic rock is composed of pre formed magmatic rock, sedimentary rock or metamorphic rockMetamorphismAnd formed rock.
Deep crust andupper mantleThe upper part ofdeteriorationRock composition.Within 16km below the surface, igneous rock accounts for about 95%, sedimentary rock is less than 5%, and metamorphic rock is the least, less than 1%.The surface of the crust is dominated by sedimentary rocks, which account for about 75% of the continental area, and the ocean floor is almost completely covered by sediments.petrologyIt mainly studies the material composition, structure, structure, classification and naming, formation conditions, distribution rules, genesis, metallogenetic relationship andevolutionProcess, etc.Other generaGeoscienceIt is an important basic discipline in.
What are the three rock types?
Rock is an aggregate of minerals, which is the main material of the crust.The rock can be composed of one kind of mineral, for example, limestone is composed of only one kind of mineral calcite;It can also be composed of various minerals. For example, granite is composed ofquartz、feldspar、micaAnd other minerals.Most of the materials that make up rocks are inorganic materials.Rocks can be divided into three categories according to their genesis, but since nature is a continuum, it is difficult to really divide into three lithology according to our classification, so there will be some transitional rocks, for example, tuff (formed by volcanic dust and rock blocks falling into the surface or accumulated and cemented in water) may be classified as sedimentary rock or igneous rock,But generally we can divide it into three major categories: sedimentary rocks account for 66% of the surfaceSurfaceThe main rock types.Formed rocks are changed into debris after weathering, or formed by biological remains, and then eroded, deposited, and petrified.These rocks are all layered. The first one to deposit is in the lower part. The older the age is, the newer the age is. This is called the superposition layer rule.When rocks are deposited, they often contain biological remains, which can be preserved well after being buriedFossil；There are no fossils in igneous rocks.
classification
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Rocks are mainly divided intoigneous rock（Magmatic rock）、sedimentary rockandMetamorphic rockThree categories.In the whole crust, igneous rock accounts for about 95%, sedimentary rock is less than 5%, and metamorphic rock is the least.However, in different spheres, the distribution proportion of the three rocks varies greatly.75% of the rocks on the surface are sedimentary rocks and only 25% of igneous rocks.The deeper away from the surface, the more igneous and metamorphic rocks.CrustDeep andupper mantle, mainly composed of igneous rocks and metamorphic rocks.Igneous rocks account for 64.7% of the total crustal volume, metamorphic rocks account for 27.4%, and sedimentary rocks account for 7.9%.amongbasaltandgabbroAccounting for 65.7% of all igneous rocks,GraniteAnd other light colored rocks account for about 34%.
The difference between the three rocks is not absolute.With the change of mineral composition, their properties will also change.As time and environment change, they will change into rocks of another nature.Therefore, some people think that this classification is more arbitrary.
Three major rock types
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igneous rock
igneous rockIs created byLavaorMagmaAfter coolingfreezingAnd formed into rock.Igneous rocks can be divided into two categories according to their genesis: one isMagmaFormed by condensation on the exposed surfacelava（Extrusive rock）；The other is intrusive rock formed by magma intrusion into the crust and slow condensation below the surface.During the formation of extrusive rock, due to the rapid reduction of temperature and pressure, it may be too late to crystallize or the crystallization is poor, which meansPumiceandbasalt；Hypabyssal rockThe magma intrudes within 3 km from the surface, and the crystal is relatively small;andPlutonic rocksThe magma intrudes into the deep crust more than 3 kilometers away from the earth's surface. Due to the high temperature and pressure, the crystallization is good.Typical intrusive rocks such asDike rock、GraniteEtc.
At present, about 700 kinds of igneous rocks have been found, most of which are formed below the surface of the crust. Their properties are different according to their chemical composition, temperature and pressure at the time of formation.Bowen's reaction series The crystallization of igneous rocks with different chemical compositions under different temperatures and pressures is described.
The temperature and pressure in the earth's interior are very high, and all the constituent materials (minerals) present molten fluid, called magmatic rock.Igneous rock, such as basalt and granite, is caused by magma intrusion into the crust or flowing out of the surface of the earth to cause lava, which is then cooled and solidified.Igneous rock is the most primitive of all rocks.The original igneous rock or sedimentary rock of metamorphic rock can change the structure or organization of its original rock, or make some minerals disappear, resulting in other new minerals, and thus become another rock different from the original rock, called metamorphic rock, such as marble changed from limestone;Slate changed from shale;Quartzite changes from sandstone, etc.Typical metamorphic rocks exist in Precambrian or orogenic regions, often with regional structure related cleavage or mineral changes.There are many kinds of rocks, but not every kind of rock can be used. In addition to the aesthetic point of view, the more important thing here is whether the chemical composition in the stone will affect the water quality, thus bringing negative effects.
sedimentary rock
Also called water rock.Under normal temperature and pressure on the surfacePyroclastic, organic matter and a small amount of cosmic matter through transportation, sedimentation and diagenesis.Sedimentary rocks are composed of granular and cemented materials.Granular materials refer to rock cuttings and some minerals of different shapes and sizes. The main components of cementation materials are calcium carbonate, silicon oxide, iron oxide and clay.It can be divided intoclastic rock, clay rock and chemical rock (includingBiochemical rock）。Common sedimentary rocks include sandstoneTuffaceous sandstone, conglomerate, clay rockshale, limestoneDolostone、Siliceous rock、Ferruginous rock, phosphorite, etc.Sedimentary rocks account for 7.9% of the crust volume, but they are widely distributed on the surface of the crust, accounting for about 75% of the land area, and the seabed is almost completely covered by sediments.
Sedimentary rocks have two prominent features: first, they have layers, calledbeddingConstruction.The layer to layer interface is called layer, usually the followingrock stratumIt is older than the rock stratum above.Second, many sedimentary rocks have the remains of "stony" ancient creatures or traces of survival and activity - fossils, which are used to determine the geological age and researchPaleogeographic environmentThe precious materials of the earth are called "pages" and "words" to record the history of the earth.
Igneous rock, sedimentary rock and metamorphic rock can be transformed into each other.Igneous rockSedimentationBecome sedimentary rockMetamorphismIt becomes metamorphic rock.Metamorphic rocks can also become new sedimentary rocks again. Sedimentary rocks become metamorphic rocks through metamorphism. Sedimentary rocks and metamorphic rocks can be melted and become igneous rocks again.[2]
The rock has a specific gravityporosity、compressive strengthAnd tensile strength, etcphysical propertyIt is a factor to be considered in construction, drilling, tunneling and other projects, and also a carrier of various mineral resources. Different types of rocks contain different minerals.Taking igneous rocks as an example, basic ultrabasic rocks andSiderophile element, such as chromium, nickelPlatinum groupElements, titanium, vanadium, iron, etc;Acid rocks are related to lithophile elements such as tungsten, tin, molybdenum, beryllium, lithium, niobium, tantalum and uranium;Diamond is produced only inKimberliteandK-Mg lamprophyreMedium;ChromiteProlificacyYu ChunPeridotiteMedium;Tungsten tin deposits are abundant in early Yanshanian granites in South China;Independent tin deposits, niobium, tantalum and beryllium deposits are often formed in late Yanshanian granites.Oil and coal occur only in sedimentary rocks.PrecambrianThe iron ores in metamorphic rocks are worldwide.Many rocks are also important industrial raw materials, such as BeijingWhite marble(a kind of white marble) is famous at home and abroadBuilding decoration materials, NanjingRiverstones, FujianShoushan StoneQingtian stone in Zhejiang is a good craft stone, even though the river sand and pebbles that are not noticed are very useful building materials.Many rocks are also important raw materials for traditional Chinese medicine, such asMaifan stone(A kind of intermediate acid vein rock) is a very popular medicinal rock.Rock is also an important factor of tourism resourcesDachuanStrange peaks and caves are all related to rocks.Our ancestors have been using rocks since the Stone Age. Today, with the high development of science and technology, people's clothing, food, shelter, transportation, travel, and medicine can not leave rocks.Studying, using, hiding, playing and loving rocks are no longer the patents of scientists, but gradually become a part of the lives of the masses.
Specific categories
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Fluorspar
Also called soft water amethyst, soft water green crystal, fluorite.Stone color is yellow, greenblue, purple, etc.It has glass luster, and fluorescent light will appear when heating. The crushed stone slag can be used as the filter material in the filter.In industrial production, it is often used as auxiliary material for smelting metal and manufacturing fluoride, and can also be processed into low-grade jade.The origin is Jinhua, Zhejiang, De'an, Jiangxi and Longhua, Hebei.
Malachite
It is actually the tailing stone of copper mine. It is green in color and has luster. The stone surface has a round pattern like a peacock tail, so it is named.The copper ions in it will slowly dissolve in the water, helping to supplement the need of water plants for copper, but it is not allowed to place too much or too large to prevent excess copper.
ross quartz
It is also called Yangnanyu or Rose Quartz.Available in rose, light red and white.The main components aresilicon dioxide。It is produced in Inner Mongolia and Shanxi.
Wood fossil
It is also called silicon fossil and tree fossil. Fifteen million Jurassic trees evolved into fossils through crustal movement and volcanic ash burial.There are grey, yellowish brown, brown and black, etc.Wood fossils in the aquarium can vividly show the vicissitudes of history. The wood fossils themselves were originally organic matter, which evolved into inorganic matter after hundreds of millions of years. Their shapes still retain the outline of trees, and even can clearly see the growth rings from the cross section, which is unmatched by any other rock.In the aquarium, green water plants can represent, dead cairns can represent, and wood fossils can represent the ancient times. This long history process is completely displayed in a small aquarium with an exaggerated technique.From an aesthetic point of view, aquatic plants, sunken trees and wood fossils belong to the same sex but different materials, which not only represent a unified composition, but also have the characteristics of change, that is, harmony and jumping.Wood fossil is a rare precious stone in the aquarium, which is produced in Liaoning and Zhejiang in China.
Biotite schist
It is a mica ore, black with mercerization.The main composition is biotite, which is composed of clay rock, siltstone or intermediate and acid volcanic rock.Compact and delicate structure.It is distributed all over the country.
agalmatolite
It is composed of acid volcanic rock and tuff, jade like texture, yellow, light yellow and white.It is distributed in Jiangnan area of China.
Ichthyolite
It is also called tiger skin stone and pine skin stone.The color is cyan, cyan, yellow and red, with white spots and holes.It is produced in Changxing, Zhejiang Province.It is composed of limestone and is not suitable for use in aquarium.
Quartz stone
Grey black to black, with white or gray stripes inside.It is also called Yingde Stone because it is produced in Yingde, Guangdong.
Chrysanthemum stone
There are chrysanthemum shaped patterns on the white, gray or dark purple stone surface.It is produced in Liuyang, Hunan.
Huxian Stone
It is brown and oddly shaped. It is a precious stone toy. It is produced in Huxian County, Shaanxi Province.
Moire stone
It is also called wind fossil.It is made of various crushed stones, with mixed colors and vertical and horizontal grooves.It is mainly composed of carbonite, and calcium in it will be slowly coated into the water, making the water hard.Therefore, it is not suitable for use in aquarium.But it can be used in African water plants landscaping.It is produced in Geleshan and Tushan, Chongqing, Sichuan.
Wu Bishi
It is also called Kushi.The granite is hard, and the sound of percussion is clear and pleasant.There are black, white, green, brown and other colors, belonging to marble.It is produced in Panshi Mountain, Lingbi County, Anhui Province.
Kunshan stone
The stone is hard, with grooves and holes.Available in yellow and white.It is produced in Ma'anshan, Kunshan County, Jiangsu Province.
Xuanshi
White has luster.The stone is hard with grooves.It is produced in Xuancheng, Anhui.
Sand rubble
It is also called sandstone.Stone color is gray, yellow, green, etc.The stone is hard and can absorb water with grooves and holes in strip or sheet shape.It is mainly produced in western Sichuan.
Melaleuca stone
The bluish black and white schistose rocks overlap each other and are hard.It is produced in Taihu Lake, Jiangsu Province.
cobblestone
Available in various colors.It is produced in large and small rivers all over the country and can be used for African style water grass landscaping.
nature
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Seaside Rock
Rock engineeringIt is no wonder that the properties are the factors of material composition (the nature of particles themselves), structure (the connection between particles), structure (the formation environment and transformation, construction), and the present occurrence environment (stress, temperature, water).If it isrock, depending onStructural planeandRock blockIn two aspects, in most cases, the structural plane plays a controlling role.
Place of Origin
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At the beginning of the formation of the earth, the gravity of the earth's core sucked the dust in the universe, and the condensed dust turned into rocks.After weathering, the mountain rocks become rocks.Then it turned into a meteorite, which didn't fall into the earthatmosphereWhen, it is a stone, iron or a mixture of stone and iron free in outer space;If it falls into the atmosphere, it will become a meteorite we usually see when it falls to the ground without being burned by the atmosphere.In short, the so-called meteorite is the debris left by a miniature asteroid "hitting the Earth".
formation
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rock
At the beginning of the formation of the earth, it became a mountain rock. After weathering, it became a rock.Then it becomes a meteorite. When it does not fall into the earth's atmosphere, it is free fromthe outer spaceIf it falls into the atmosphere, it will not be burned by the atmosphere but fall to the ground. In short, the so-called meteorite is the debris left by a miniature asteroid "hitting the earth".Hundreds of millions of years later, there are countless rocks in the world.It is developing towards quantitative direction.
Ancient rocks occur in the crystalline basement within the continent.The representative rocks are basic and ultrabasic igneous rocks.These rocks have been transformed into richChloriteAnd hornblendegreenstone。For example, in West China in 1973GreenlandFoundIsotopic ageAbout 3.8 billion yearsGranite gneiss。In 1979, Batun et al. determinedSouth AfricaMid BobolingneissAbout 3.9 billion years old.
The metamorphic rock Akaska gneiss in northern Canada is part of the well preserved ancient earth surface.Radioactive dating shows that the Akaska gneiss is nearly 4 billion years old, which indicates that some continental materials have existed hundreds of millions of years after the formation of the Earth.
According to the zircon contained in itMineral crystalAccording to the isotope analysis results of, their "ages" are about 4.3 billion to 4.4 billion years old, and they are the oldest rock samples found on the earth so far. According to this discovery, it can be inferred that when these rocks were formed, there were already continents and oceans on the earth.After the birth of the earth 200 million to 300 million years ago, it may not be covered by hot magma as people think, but has cooled to the temperature enough to form a solid surface and ocean.Earth's sphere differentiation may have been completed 4.4 billion years ago.
explore
At present, the oldest rock found in China is the granitic gneiss in eastern Hebei Province, of which the rock age of inclusions is about 3.5 billion years.
Micro in the Warrawoona Group in Western AustraliaFossilIt is relatively complete in morphology and structure.early stageStromatoliteIt is built by cyanobacteria, and stromatolite is an indication of the existence of cyanobacteria.If blue-green algae appeared 3.5 billion years ago, it means that photosynthesis of oxygen release has already begun, which leads to a question: why did the atmosphere not accumulate free oxygen until 2 billion years ago?From 3.5 billion years ago to 2 billion years ago, there was a gap of 1.5 billion years. Why is the accumulation of oxygen so slow?Of course, there are different explanations for this.
The most important indirect evidence for the existence of the oldest life is the western Greenland banded iron formation (BIF) and the lightcarbon isotope。If the evidence is true, it can be inferred that microorganisms that release oxygen and photosynthesize have appeared on the earth 3.8 billion years ago, that is, organisms similar to cyanobacteria.According to Cloud's interpretation, BIF is caused by the periodic release of oxygen by light and microorganisms, which leads to the oxidation of ferrous iron into high valent iron.Light carbon isotopes are also indirect evidence of photosynthesis.However, the opposing opinion is that the oxygen required for the formation of BIF can be provided by the photodegradation of water molecules in the atmosphere, and the light carbon isotope may come from the thermal decomposition of carbonate.
reason
At the end of the 18th century, petrology emerged from mineralogy and developed into an independent discipline.At the beginning of the development of petrology, the main research was igneous rocks. It was not until the middle of the 19th century that metamorphic rocks were systematically studied, while sedimentary rocks were not noticed until the beginning of the 20th century.
Each rock has its specific environment of formation, later preservation and change.The following are discussed separately.
1. Granite has not been found on the planets beyond the earth through the study of astrogeology.Therefore, granite is unique in physical, chemical and biological processes on the earthproduct。The earth formed about 6 billion years ago;Around 4.25 billion yuan, the atmosphere and hydrosphere were formed;Around 4 billion years ago, life appeared, and then formedbiosphere。
1.1 At a depth of about 40km, huge pressure and high temperature make the rock plastic deformation and mineral recrystallization in plastic state. In this state, recrystallization is not sufficient, so the crystal is small and turbid.Under the huge vertical filling pressure, minerals and crystals are directionally arranged to form gneiss, which is called gneiss.It is a negative metamorphic rock formed by direct metamorphism of sedimentary rocks.
1.2 When the gneiss is subjected to horizontal compression in the deep underground, a crumpled structure is formed between the bedding and gneiss, and thus a collapse structure (that is, a curved convex mirror space caused by twisting between the layers) is generated.
1.3. If the silicoaluminal sedimentary rock continues to sink to a depth of about 60 km, the pressure and temperature have melted the rock into granite slurry, and the proportion of granite slurry is small (about 2.7). If the heavier iron slurry floating in the mantle rises and cools rapidly, and there is no time for full crystallization and polycrystal, it will form: quartz is an independent fine to medium crystal with a nearly circular shape;Feldspar is micro to fine grained.It is called aplite and is generally light colored.
1.4. If the granite slurry rises slowly and cools down, the minerals can crystallize and polycrystal calmly, that is, the single crystals of the same minerals tend to aggregate together in the liquid.In this way, medium to large phenocryst granite is formed.Most of the granite varieties in China and abroad belong to this category.
1.5. Granite slurry has crystallized but not solidified in the process of rising and cooling.At this time, the crystals are compressed, elongated, and directionally arranged to form granite gneiss, such as Guangdong Hailanghua, Fujian Vietnam White, Xinjiang Glacier White, etc.
1.6. During the rising and cooling process of granite slurry, some crystals have been formed, which then sink again and are heated, and recrystallize around the formed crystals (or nuclei) to form a crystal ring around crystal riboflavin, also known as crystal accretion, and have a clear boundary with the initial crystal riboflavin, such as Finland's Kezuan, Shandong Laizhou Pearl Red, etc.Large crystal, nearly round coral, with characteristics.
2. Rock alteration When the magma rises, cools and becomes rock, and rises to a depth of about 10km below the surface, groundwater can alter the rock through the cracks around the rock and the pores of crystal particles.Alteration can transform feldspar into kaolinite, and pyroxene and hornblende into curbite, reducing the physical properties of stone, increasing the water absorption and reducing the gloss.However, slight alteration has little impact on the physical properties of rocks, but it has changed the color of rocks and created some beautifulStone variety。
2.1 After the alteration of aplite, feldspar is transformed into kaolinite, and its physical properties are affected, such as Tianshan orchid in Xinjiang and white pearl in Jiangxi.
2.2 After the gabbro vein is altered, pyroxene and hornblende are transformed into chlorite, which turns black rocks into green rocks, such as Evergreen in Lingshou, Hebei, and Forest Green in Qixian, Henan.Although the physical properties of rocks are affected, the beautiful colors are loved by peopleHigh grade stone。
2.3 After the syenite is altered, the original gray, blue and green crystals become brown and yellow due to the reduction of the electronic value of iron, and the edge of the crystal turns into kaolinite, slightly lighter than the middle of the crystal, making the design and color of the panel three-dimensional, such as Hebei Chengde Jinzhen Pearl, foreign Brazil coffee, Brazil coffee pearl, etc., all of which are top quality stones.
3. Weathering of rocks When the rock Luozhen is behind the surface, it is exposed to the weathering of water, steam and temperature, with the depth of action ranging from 1-15m.Weathering has destroyed most of the stone deposits. Chicken claw patterns, rusty king and sand holes can be seen on the polished surface, which is not easy to polish. However, weathering has also created some unique varieties, such as Fujian rusty stone, Shandong rusty stone used for the exterior wall of the Great Hall of the People in Beijing, and jute produced in Jiangxi, Guangdong and Guangxi,This type of deposit belongs to surface weathering type, with a thickness of about 10m along the east.It is easy to mine and has high value.The jute series abroad mostly belong to this type, which is characterized by the fact that the material (iron) that affects the discoloration of rocks comes from the surface and is caused by leaching of surface water.
application
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Building materials
onemarble: Rock surface of marbletextureDelicate, often used as wall or floor.Because marble is formed bylimestoneIt is formed by metamorphism, mainly composed ofcalcium carbonateTherefore, it is also the raw material for manufacturing cement.Marble is soft and delicate, and is a good stone for sculpture. Many famous statues are made of marble, such as the famous Venus statue.Others, such as walls or decorations, are often polished from marble, such as vases, ashtrays, tables and other household items.
twoGranite: The only local graniteJinmenI can see that, so the old houses in Jinmen are almost made of granite.The granite used in Taiwan's temples is from Fujian, and is mostly used for dragon pillars, floor tilesstone lion。
threeslate: Because it is easy to crack into thin plates and is easily obtained in mountainous areas, the aborigines still use slate as building materials to build slate houses or walls.
fourconglomerate: Some conglomerates contain geesePebbleAnd sand, andcementedIt is bad and easy to disperse them. For example, this kind of conglomerate is found in the Quaternary Toudangshan Formation in western Taiwan, where pebbles and sands are building materials.
5. Limestone: The most common limestone in Taiwan is formed by corals, commonly known asCoral reefLimestone.In Penghu, coral reefs are commonly known as "rocks", which are used by residents as wall building materials to shield strongNortheast monsoonAnd protect crops.
sixmudstoneBecause its main component is clay, it has been used as the raw material of bricks, tiles and pottery since ancient times.
sevenAndesite: Due to its hard material, it is also often used as the dragon pillars of temples, stone carvings on walls, tombstones, floor tiles, etc.
Precious gems
If minerals are hard, rare, durable, transparent and beautiful in color, they are often used as decorations, generally called gems. The following is a brief introduction to common gems:
1. Diamond: commonly known as diamond, it has many colors, such as light yellow, brown, white, blue, green, red, etc., of which colorless and transparent have the highest value.
twocorundumCorundum also has many different colors, such as red corundumRubyBlue corundum is called sapphire.Its chemical composition isAluminium trioxide。
threeOpal: Generally colorless or white, and some have special halos.
4. Crystal: purequartzThe single crystal is called crystal. It has different colors due to different impurities, such as:Citrine, Amethyst, etc.The fibrous microcrystalline polymer of quartz is calledChalcedony；The granular microcrystalline aggregate of quartz is calledFlintThese two minerals are important jades in Taidong County.
Refining metals
1. Gold ore: gold bearing rocks are weathered andErosion, gold will be separatedNatural goldBecause gold is much heavier than sand, it is easy to deposit. After washing, it becomes gold.
2. Chalcopyrite: Chalcopyrite is the main mineral for refining copper.
threegalena: Galena is lead gray, with cubecleavage Is the most important lead bearing mineral.
fourHematite: Hematite is iron gray or reddish brown in appearance, which is the most important iron bearing mineral.
fivemagnetite: Magnetite is an iron bearing mineral, which is magnetic and absorbs iron bearing substances.
Pigment
Some minerals have special colors and can be used as pigments, such as blue chalcopyrite, greenMalachite, redCinnabar。
Other uses
1. Quartz: Quartz is the main raw material for manufacturing glass and semiconductors, such as:Miaoli CountyIn the upper Fuji sandstone of Wenshui RiverQuartz sandIt is the main material for making glass.
twocalciteCalcite exists in marble and limestone and is the main raw material for cement production.
threeMuscovite: Muscovite is often used as an insulator material in electric heaters because of its non-conductive, non-conductive and high melting point characteristics.
4. Graphite: low hardness, with grease luster,StreaksIt is black and is often used to make pencil lead. In addition, graphite can also be used as lubricant, electrode, crucible, etc.
fivesulfur: Hot springs in volcanic areas contain yellow sulfur.
6. Plaster: Plaster is generally used to fix the fracture and injury, or make a statue, and also used in the construction industry.
sevenapatite: It is used to produce phosphorus fertilizer for agriculture.
eightserpentine: Containing magnesium, it can be used in steel making industry.
It refers to the mineral with large content in the rock and plays a major role in determining the name of the rock category.
for exampleGranitoids, the main minerals are quartz and potassiumfeldsparWhen the quartz content is less than 75% and the potassium feldspar content is more than 25%, the rock isSyeniteWhen the quartz content is greater than 95%, it is classified as quartziteGraniteQuartz and feldspar are the main minerals.
auxiliary mineral
It refers to the mineral in the rock whose content is lower than that of the main mineral, which does not play a major role in the classification of the rock category, but plays a certain role in determining the rock species, and the content is generally less than 15%.
For example, for diorite, quartz is a secondary mineral, and diorite contains quartz (up to 5%)Quartz dioriteIf there is no quartz or quartz is less than 5%, it is called diorite, but both belong to the diorite category, so quartz is a secondary mineral for diorite.
Accessory mineral
The content of rocks is very small, usually less than 1%, and they are not usually involved in rock naming. Only when they have special significance for rock genesis or mineralization, they are selectively used as decorations before the rock name, such as monazite granite,MonaziteIt exists as accessory minerals, but indicates that the granite is rich inrare earth element。
weathering
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The rock is broken, loose andMineral compositionThe phenomenon of secondary change.The action that causes the above phenomenon is called weathering.Divided into: ①Physical weatheringeffect.It mainly includes rock expansion and contraction caused by temperature changefractureExpansion caused by freezing of reclaimed water and salt crystallization, and expansion caused by unloading of rocks. ②chemical weathering effect.Including: dissolution of water on rocks;The mineral absorbs water to form new water bearing minerals, thus causing rock expansion and disintegrationHydration；Minerals react with water and decompose intoNew mineralOfhydrolysiseffect;The rock is damaged by free oxygen in air or wateroxidation。③Biological weatheringeffect.It includes the damage of animals and plants to rocks, and its mechanical damage to rocks also belongs toPhysical weathering, the decomposition of its corpse will also erode the rockChemical weathering。So is man-made destructionRock weatheringImportant reasons.Weathering degree of rockIt can be divided into completely weathered, strongly weatheredWeakly weatheredAnd slight weathering.
About 200 years ago, people might have thought that mountains, lakes and deserts were eternal features of the earth.But now we know that mountains will eventually be weathered and denuded into flat land, lakes will eventually be filled with sediment and vegetation, and deserts will move with climate change.The matter on the earth is moving endlessly.Most of the rocks exposed on the surface of the crust are in different physical and chemical conditions from those when they were formed, and the surface is rich inoxygen、carbon dioxideAnd water, so the rock is very easy to change and destroy.The whole rock is changed into fragments, or its composition changes, and finally the hard rock becomes loose debris and soil.The process of mechanical fragmentation and chemical decomposition of minerals and rocks under surface conditions is called weathering.The process of removing the products of weathering from the original place due to wind, current, glacier and other forces is callederosion。
Physical weathering refers to the action that surface rock is mechanically broken in situ without changing its chemical composition or new minerals.Such as thermal expansion and cold contraction of mineral rocksFrost Wedging , spallation, salt crystallization and other actions can make the rock from large blocks into small pieces or even completely broken.Chemical weatheringIt means that the surface rock is exposed to water, oxygen andcarbon dioxideThe chemical composition and mineral composition are changed and new minerals are produced.Mainly through dissolutionHydrationHydrolysisCarbonation and oxidation are carried out in the equation.
Although all rocks will be weathered, not all will change along the same path or at the same rate.After years of observation of weathered rocks under different conditions, we know that rock characteristics, climate and topographic conditions are the main factors controlling rock weathering.Different rocks have different mineral compositions and structures, and the solubility of different minerals varies greatly.JointThe distribution of bedding and pores and the granularity of minerals determine the fragility and surface area of rocks.The difference of weathering rate can be seen from the steles of different rock types.For example, granite steles are mainly composed ofSilicate mineral。This kind of stone tablet can well resist chemical weathering.The marble stele is obviously vulnerable to weathering.
Climate factors are mainly manifested by temperature, rainfall and biological reproduction.In a warm and humid environment, the temperature is high, the rainfall is large, the plants are dense, and the microorganisms are active,Chemical weatheringThe speed is fast and sufficient, and the decomposition of rock can develop in depth to form extremely thickWeathered layer。In polar and desert regions, due to dry and cold climate, chemical weathering has little effect, and rocks are easily broken into angular fragments.The most typical example is to move the Cleopatra granite spire tower, which has stood in dry Egypt for 35 centuries and is well preserved, to New York City, where air pollution is seriousCentral ParkOnly 75 years later, it was totally different.
The height of the terrain affects the climate: the temperature and climate of the foot and the top of the mountain in the middle and low latitudes are very different, and their biological interface appearance is significantly different.Therefore, there are significant differences in weathering.The degree of relief is also of universal significance for weathering: mountainous areas with large relief,Weathering productSusceptibleexternal forceDenudationBedrockExposed, accelerated weathering.The direction of the hillside involves climate andsunshineFor example, the sunny side of the mountain has strong sunshine and much rain, while the sunny side of the mountain may not melt ice and snow all the year round. Obviously, the weathering characteristics of rocks are quite different.
The denudation and weathering complement each other in nature. Only when the rock is weathered can it be easily denuded.When the rock is denuded, fresh rock can be exposed to continue weathering.The transportation of weathering products isDenudationThe main embodiment of.WhendebrisWhen moving media, such as wind or waterriverbedAnd the lakeshore zone.In this way, more debris will be generated forSedimentationMaterial conditions are provided.
Under the action of sunlight, water, organisms and air, rocks are gradually destroyed and decomposed into sand and soil, which is called weathering.Sand and soil are the products of rock weathering.
1、 Weathering of rocks.
The loosening, peeling and cracking of rocks are all weathering phenomena of rocks.
2、 The cause of rock weathering.
Lunar rocks
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2022On October 31, the world's first 1:2.5 million lunar rock type distribution map led by Shandong University was released.The map divides the lunar surface materials into three categories: lunar sea rocks, non lunar sea rocks and special rocks, representing a total of 17 rock types[3]。
Plastic rock
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In April 2023, an international research team found a new form of plastic pollution: plastic waste film chemically combines with rock to form "plastic rock".[4]
