Kimberlite

Classification：Igneous Rock

Kimberley rock is a kind of ultramafic rock, which consists mainly of olivine and one or more substances of chrysotile, serpentine, diopside, calcite, calcite, and no white garnet. Kimberley rock is an important economic value rock type, and it is the main source of diamonds.

Kimberley rock is a rare alkaline ultrabasic shallow super shallow rock without feldspar. Is porphyritic structure and (or) brecciated structure of mica peridotite. Kimberley (Kimberley), discovered in South Africa in 1887, is known as "breccia mica peridotite". It is one of the most important igneous rocks of diamond production.

Summary：
The Kimberley rock is a kind of alkaline ultrabasic rock. Is porphyritic structure and (or) brecciated structure of mica peridotite. It was named after the discovery of Kimberley in Africa in 1887. The old breccia mica peridotite. A black, dark green, gray and other colors. It is one of the most important igneous rocks of diamond production. Chang Qun appears. The famous Kimberley rock in South Africa is a group of rock groups made up of more than 10 famous rock pipes. The Kimberley rocks with porphyritic structure and rich in coarse olivine are rich in diamond, and are microscopic porphyry, rich in Kimberley rock rich in gold mica and poor in diamond.

China, Shandong, Liaoning, Xinjiang Hotan, Queensland and Northern Territory and so on all have their output, which are similar to shallow intrusive rocks with rock veins and volcanic throat.
Its age was dominated by the Cretaceous period. Kimberley rock is a suite of rocks including volcanic breccia (or tuff) to shallow intrusive rocks. Common types of tuffaceous breccia rock rock, Kimberley Kimberley and Kimberley rock. Kimberley rock is mainly distributed in the area of stable tectonic movement, mostly rock tube, sills and dykes output.
The main mineral concerned is diamond, which is the parent rock of diamond. However, when diamond is formed, the formation mechanism of Kimberley rock is strict, and diamond must be formed under the sudden blasting from high temperature and high pressure to low temperature and low pressure open environment.

The mineral composition of Kimberley rock is complex, which can be generally divided into 3 types.

1. Primary minerals
Such as olivine, mica, garnet, ilmenite, apatite, Jin Hongshi, diamond and so on. Olivine is the main rock forming mineral of Kimberley rock. There are several times in the past few years. Olivine and phenocryst are mostly oval and easy to be replaced by serpentine. Generally, the content of magnesium and granite is not much, but it is an important characteristic mineral in Kimberley rock. It often appears in the circular or angular debris. It is one of the associated minerals of diamond. In the phenocryst and matrix, the content of gold mica is large, and it is yellow green, brown yellow and phenocryst. It can reach several centimeters. The matrix is mostly 0.1~0.5mm, easily eroded into chlorite and water mica. The content of high content of Kimberley mica is poor.

2.The mantle crust minerals
are derived from the upper mantle and other rocks or xenoliths in the deep crust, such as the olivine of the pomegranate two peridotite and eclogite, the trapezite, chrome spinel and magnetite, as well as the dolomite, calcite, spite, and tourmaline in the surrounding rock inclusions.

3. Altered secondary minerals
Such as serpentine, magnetite, pyrite, biotite, chlorite and carbonate minerals. Magnesian garnet is an important characteristic mineral as well as an indicator mineral for finding diamonds. The edge of mineral particles often changes to chlorite, biotite, serpentine, calcite, overlying rock, water mica and iron oxides. When it is completely replaced by iron oxides and serpentine minerals, it becomes black spherules, commonly known as black beans. The magnesia - aluminite has a special two - light property. It is red under artificial transmission light and green in sunlight.

Structural structure:
Kimberley rock often has porphyritic texture, fine structure and volcano clastic structure. Block structure, breccia structure and rock ball structure. The macular structure is mainly olivine and gold mica. The olivine is in a round shape and is generally subjected to intense serpentinization and carbonation alteration. The matrix is microscopic porphyry and consists of olivine, gold mica, chromite, ilmenite, perovskite, apatite and so on. The brecciate structure is breccia complex, with debris from the upper mantle and debris from shallow surrounding rocks. The existence of a lot of breccia reflects the characteristics of Kimberley magma explosion. In addition, in some of the Kimberley rock canister in China and the world, it is commonly known as the Kimberley rock ball, commonly known as the "phoenix egg", and the size of the cherry to the egg, which is one of the prospecting criteria for the primary diamond deposit.

Chemical composition:
Kimberley rock has the following characteristics: 1. It belongs to silicic acid unsaturated rock. Compared with the average composition, SiO2 is low (35%), K2O>Na2O, Al2O3> (K2O+Na2O). (2) MgO/SiO2 is close to 1. When the rock is strongly carbonated, MgO is replaced by CaO, so that the content of (MgO+CaO) is nearly equal to that of SiO2. It is rich in H2O and CO2, which causes strong alteration of rock. (4) in the late stage of magma, K2O participates in the formation of gold mica. 5. In the trace elements, the incompatible elements, including Cr, Ni, Co, and Rb, Cs, Ba, Sr, Zr, Nb, Th, REE, P, are mainly included in the perovskite and apatite. The simple linear REE distribution pattern of Kimberley rock and the most La/Yb ratio of La/Yb are 80~200, which are higher than most other mantle derived mafic and ultramafic magmatic rocks, which reflect the characteristics of the magma of Kimberley rock.

Production and times:
A small number of 1 square kilometers, the largest not more than 2 square kilometers, often appear in groups, the famous South African Kimberley rock is a group of more than 10 famous rock canister. The thickness of Kimberley rock dyke is small, generally less than 2 meters, but the length is large, and the longest is 65 kilometers. Kimberley rock sills, Kimberley rock volcano, volcano lake and volcano sedimentary is rare. The geological age of Kimberley rock has been formed in the world, which is mainly formed in the late stage, but in a considerable scale, the Kimberley rock belt or region is often many times.

Cause:
The Kimberley rock formation is still explored through the high pressure and high temperature experimental study of the peridotite CO2-H2O system. The Kimberley rock magma is considered to be a carbonized peridotite mantle consisting of gold mica, magnesite, and pomegranate two peridotite under the rich CO2 condition. The low eutectic effect of the peridotite in the temperature and pressure conditions of PPA and 1000~1300 C is produced. Raw。 The diapir mode of releasing and permeating the C-H-O mainly from the deep mantle is also proposed, which makes the solid phase line of the peridotite -CO2-H2O system cut at the depth of the continental shield geothermal line at the upper and lower depths of 260 km, and thus the partial melting and the adiabatic rise of the molten diapir have occurred. The Kimberley rock magma rapidly rising from deeper parts may form Kimberley rock with diamond. The melting conditions (P-T-fO2) of the mantle peridotite in the presence of C-O-H fluid have been studied, which will help to understand the genesis of the magma and the genesis of the diamond in the mantle under the continental mantle.
From the trace element geochemistry, the high La/Yb ratio of Kimberley rock is mainly constrained by the matrix apatite with high La/Yb ratio, and mainly reflects the ratio of the source area. Also found in some two garnet peridotite inclusion metasomatic minerals and potash magnesium titanate amphibole in the body. Many geochemists believe that Kimberley rock is related to the low degree partial melting of the metasomatism mantle source area, which is highly enriched in incompatible elements. It is generally believed that the most favorable geotectonic environment for the formation of Kimberley rock and rich in diamond is the region with the ancient continental cratonic crust and the subsequent stable caprock.

Metallogenic relationship:
Not all Kimberley rocks contain diamonds, but the number of diamond rich Kimberley rock bodies is few. One problem that has not been solved is whether diamonds are crystallized directly from the Kimberley rock magma rich in the rich CO2 Kimberley rock or the upper mantle xenoliths in the upper mantle of the mixed Kimberley rock, or there are two cases. Diamond is found in the upper mantle pomegranate, two peridotite and eclogites. Although there are still different views, people often have the following empirical or statistical rules for the poor and rich diamond containing the diamond: (1) the Kimberley rock with the pyroclastic structure, rich in the mantle plume or its mineral inclusion in the peridotite of the granolite, Fang Hui peridotite and the pure olivite, is rich and good in quality, containing the surrounding rock of the earth's crust. More detritus, the poorer. The porphyritic structure of Kimberley rock containing diamond rich, a micro structure is poor. 3. Rich olivine and coarse-grained Kimberley rocks contain diamonds rich in gold and rich in gold mica, and contain poor diamonds. The higher the Mg and Cr, the higher the Mg and Cr, the richer the diamond, the high content of chromite and the Cr/ (Cr+Al) >90% in the chromite, the high content of the diamond, the higher content of the diopside (Cr2O3>1.2%) rich in the rich Cr poor Al and the high Cr (Cr2O3>2.5%) of the magnesia, and the high content of the diamond.
The experimental research on the genesis of diamond shows that when the C-O-H system exists in the upper mantle, only the two constraints of pressure and temperature are not sufficient to limit the nucleation and growth of the diamond. The stability of the diamond is also controlled by fO2, and only the strong reduction environment coincides with a certain range of fO2 at a higher temperature. It can keep diamond stable -- Hagt (Hag-gerty) mode. The pattern includes a subcontinental craton lithosphere, whose circumferential boundary is related to the active belt. The interface between the bottom of the lithosphere and the top of the asthenosphere is concave, and the distribution of isotherms is similar to the interface. The temperature of the bottom of the lithosphere is nearly 1300 degrees. The diamond conversion curve is convex. There are abundant carbon sources in the region defined by the concave convex surface and the pressure, temperature and fO2 conditions conform to the formation and stability of diamond, while the source area of the Kimberley rock magma is deeper in the asthenosphere of less than 260 km. The Kimberley rock volcano, which belongs to the central position in this model, will produce a standard, large lithospheric diamond combination of Kimberley rock and a combination of pomegranate two - peridotite, Fang Hui peridotite and pure peridotite and its constituent minerals. The inclusion assemblage is one of the signs that indicate whether the host Kimberley rock contains or contains diamonds and the best quality.

Discovery and exploitation:
Kimberley is a small town in South Africa. In 1867, the world first found the parent rock that contained diamonds. The rock was named Kimberley rock, which contained 20% to 30% diamonds, with less than 5% industrial value. The Kimberley bearing rock bodies with industrial significance are mainly distributed in South Africa, Botswana, Zaire, Australia, Russia and China. The geological exploration of diamond in China began in 1950s. It has been found that there are more than 400 Kimberley veins, which are distributed in 3 provinces of Liaoning, Shandong and Xinjiang. Although some of them contain diamond, there are few industrial values.
In 1866, the history of diamond exploration in the world has undergone a historic change, and the first discovery of diamonds in South Africa. By 1870, the number of people directly searching for diamonds reached more than 50 thousand. Diamond placer has large scale and high grade was found in the Orange River and its tributaries. In 1870, the Kimberley rock and tube, the sub Hess Feng Tan rock and the "Douto Bea F Pam" rock canister were first discovered. In 1871, the world famous "Kimberley", "derbees" and "Bert Feng Tan" 3 rock canisters were found near the city of Kimberley, and thus the name of "Kimberley rock" was created.
Before 1870, diamonds discovered all over the world were produced from placer deposits. One of the largest "pimir" Kimberley rock canister in South Africa was found in 1902. Since the barrel was put into production in 1903, the 78 million carats of diamond have been picked up by the end of the last century in the late 70s. The rock tube produced many famous large diamond, such as the gem diamond "the largest Cullinan" etc.. The diamond type of the rock tube is also very rich, up to 1000 kinds, and diamond quality is very good, gem grade diamond accounts for about 55%. Since the middle of nineteenth Century, South Africa has replaced Brazil and become the main producer of diamonds in the world.
In 1907, the American geologist Gianotten (Janot) accidentally discovered a 0.1 carat diamond in the alluvium of the chynnna River in the Zaire census. Since then, people have found many diamond placer with similar method of gold rush. After more than 30 years of exploration, not only the most abundant residual slope and alluvial sand in the world have been found, but the first group of Kimberley rock canister was found near the city of M Bu Ji MA in 1946. Shortly thereafter, in the southwest of the city of Mubuji maj 30km at Jibua area and to find a new Kimberley rock cylinder group. Since 1953, diamond production in Zaire has surpassed South Africa and has become the most productive diamond producer in the world.
In 1908, Kimberley rock canister was found in Namibia (southwest Africa). Later exploration proved that there is the largest coastal diamond deposit in the world, the quality of diamond is the best, and gem grade diamond accounts for 95%.
Since twentieth Century, diamonds have been found in many African countries. In 1910 in Libya, in 1912 in Angola, in 1913 in Tanzania and the Central African Republic, in 1919 in Garner, in Ivory Coast, in Sierra Leone in 1930, in 1955, in Mali, and in Botswana and other countries in Botswana. These countries are mainly found in diamond placer, and only a few are primary deposits of Kimberley rock.
Diamonds were found in Tanzania in 1913. In the recent 30 years, although more than 200 Kimberley rock bodies were found, most of them contained no diamonds. Until 1940, the largest diamond bearing Kimberley rock barrel in the world was found by the Canadian geologist J.T. Williamsen in the siyyang plus region, named the "m WaMu" rock, with a surface area of 1 million 460 thousand square meters and an estimated diamond reserves of about 50 million carats.
Botswana began to use heavy sand method to survey and find diamond from 1955. After more than 10 years of work, the world's second largest Kimberley rock canister "Orapa" rock tube was not found until 1967. 1973 found the rich gem diamond "jiewang" rock tube. Since then, Botswana has become the most important diamond producer in the world.
Russia and the former Soviet Union have gone through a long and tortuous historical process to find and discover diamond deposits. Russia's first diamond was discovered in gold bearing platinum Placer in Ural in 1829. Since then, during a long period of more than a century, the general survey and search of diamond in this area of Ural have never been found, except for the discovery of a small amount of diamond sand. In 1937, the famous geologist B.C. Sopo Lev compared the Siberia platform with the South African platform rich in diamond, and found that the geological features of the two were very similar. Therefore, it is suggested that there may be a primary diamond deposit of Kimberley rock in the Siberia platform. Since 1945, the Soviet Union has carried out a diamond survey in Siberia platform. After 10 years of work, the first Kimberley Rock Cylinder - "flash" cylinder was discovered until 1954, along the Dahl Deng river with magnesia as a symbol mineral. After 1955, many Kimberley rocks and rocks were found in the area. Thus, after the 1971, the output of diamond in the Soviet Union surpassed South Africa, ranking second only in Zaire.
In 1851 Australia southeastern New South Wales gold dredger mining of gold placer and cassiterite when first discovered diamond. After more than a century, it was not until 1970s that the key areas of Diamond Prospecting were moved from the east to the northwest, and a batch of diamond bearing Kimberley rock canister was found in the Kimberley area of Western Australia. The largest one has 840 thousand square meters of surface area, high diamond content and good quality. In particular, in 1979, a new type of diamond primary deposit, a primary diamond - and - magnesium - type diamond type deposit, was discovered, which made Australia the most important diamond producing area in the world. It is worth noting that the Australian "Argyll" rock tube contains a certain number of bright colored rose and pink diamond grade diamonds, a rare treasure, and an average of more than $3000 per carat diamond. Among them, a 3.5 CARAT ROSE, high quality and high quality diamond grade diamond sells for 3 million 500 thousand dollars. In addition, a few blue gem grade diamonds were found.

Born in the depths of the earth people often say that the formation conditions of diamond, toughened and hardened into steel, than the stern to more than a thousand times! As early as hundreds of millions of years ago, the earth was born at the beginning of the earth, 150 to 200 kilometers from the surface of the earth's mantle, with a high temperature of 1000 to 1300 degrees, about 4500 - 60000 atmospheres. In such a high temperature, extreme pressure and reduction (anoxia) environment, carbon atoms crystallize to become valuable diamonds. This condition is extremely rare. Billions of diamonds formed on the earth are also extremely precious.

She slept in the depths of the earth for billions of years, and has been waiting for the opportunity to come to the world. The outbreak of violent volcanoes made all of this possible. The volcanic eruption formed a unique Kimberley tube that made magma like a lift, carrying 150 kilometers of diamonds and other rocks and minerals, going up through the mantle, breaking through the earth's crust and coming to the surface. They were discovered and exploited by humans in the form of diamond blank (Yuan Shi).

After thousands of million cut grinding is the end of beautiful light and not all diamonds, diamond jewelry can become. The average diamond content is only twenty percent in gem, while the other eighty percent can only be used in industry. To get the original stone of 1 carat diamond, it needs 250 tons of Kimberley rock, and it can only polish about 20 to 50 points of diamond finished.

Diamond blanks were carefully selected from a large number of raw ores and shipped to diamond processing and cutting bases in the US, India, Israel and Belgium. Here, they must complete from the rough diamonds (Yuan Shi) to treasure the metamorphosis. After thousands of cutting, grinding and polishing, the number of carat of diamonds is losing, but its cleanliness is getting perfect, and the color and luster are glittering and glittering. There are countless bright and mirror like sections, so that diamonds can reflect the dazzling and intoxicating beauty.