Shulou(Shulou.com)11/24 Report--

For the use of red, China is incomparable to any other country or region, in many colors, only red is called "China". [1]

Scarlet is one of the important traditional colors in our country. In ancient times, scarlet was a positive color. In the Han Dynasty, scarlet symbolizes Vermilion Bird, referring to the south. Scarlet is made of an opaque cinnabar, named after the red of cinnabar, so it is called "scarlet". The purest cinnabar comes from China, which is the first country to extract color from natural cinnabar ore and use it. Zhu Hong has been used since ancient times, from oracle bone inscriptions, alliance letters of Spring and Autumn princes, imperial approvals, royal palace walls, down to the scarlet doors of officials or rich families, and women for powder rouge and decoration. Scarlet runs through the five thousand years of history of our country, from imperial power to aristocracy and worship, to ordinary people and daily life. That touch of red is like the rising sun, so scarlet is also known as "Chinese red", which contains the meaning of prosperity, lively and peaceful, this time let's talk about the story of cinnabar.

Chinese red

Oracle Bone inscriptions and Houma Alliance

Carmine and rouge cinnabar, also known as cinnabar (official mineral name), Dansha, Chidan, mercury sand, are mercury sulfide (HgS) minerals, containing 86.2% mercury. In ancient China, it was also an important raw material for alchemy. In ancient times, the best quality cinnabar was produced in Chenzhou (present-day Yuanling, Hunan and other places), so it was named cinnabar. [2] cinnabar and Dansha are created by people according to their color characteristics. The high-quality Chen placer is bright red, with King Kong luster to metallic luster, dense block and translucent plate or canine shape. [3]

Chen placer is the main producer of cinnabar in China, and other producing areas in the world include Almaden in Spain, Eudrio in Italy, and the coastal mountains of California in the United States. Mercury mines are distributed in nearly 20 provinces, municipalities and autonomous regions in China. The main producing areas are Tongren in Guizhou and Xinhuang in Hunan as the center. As the mercury content of cinnabar is as high as 86.2%, it is an important part of mercury ore. [4]

Mercury deposits in China have the following characteristics: 1 Precambrian (Precambrian) began in the earliest geological stage and ended about 570 million years ago. From the Tertiary to the Tertiary (the strata formed in the Cenozoic and Tertiary), mercury mineralization occurred in almost all ages. In terms of reserves, the Cambrian is the most, accounting for more than 80% of the country's total mercury reserves, followed by Devonian, Sinian and Permian. The metallogenic age of mercury deposits is Mesozoic and Cenozoic, and the genesis is mainly hydrothermal deposits.

(2) the surrounding rocks of mercury deposits (relative to the rocks around a certain crustal material) are sedimentary rocks, the most important ones are littoral, bay and shallow marine sedimentary limestone, dolomite, shale and sandstone in marine environment, mainly marine sedimentary carbonate rocks (marine deposition refers to a series of deposits produced by marine dynamic processes in the marine environment, including debris from land, bones and remains of marine organisms. Therefore, it is often dominated by carbonate deposits), and the mineral composition is simple. The most common minerals are cinnabar, quartz, dolomite and calcite, in which mercury deposits account for more than 80% of the total reserves, and few occur in clastic and magmatic rocks. Mercury deposits in carbonate rocks are closely related to anhydrite and organic matter in sedimentary facies.

(3) Mercury deposits are distributed in both the platform area and the geosyncline area, especially in the Yangtze quasi-platform. Most mercury deposits are related to deep faults and mainly occur in the depression area beside them, mostly single mercury ore. In some deposits, mercury is associated with other elements, such as mercury antimony, mercury arsenic, mercury gold and so on.

(4) magmatic rocks related to mercury deposits have not been found around almost all the important mercury deposits occurring in sedimentary rocks. Mercury mineralization is far away from igneous rock mass, and igneous rock mass is distributed in almost no mining area. From a regional point of view, the occurrence of mercury deposits and magmatic intrusive horizons are also quite inconsistent, the two can be said to be incompatible.

(5) according to the results of homogenization method of gangue mineral inclusions associated with cinnabar, the ore-forming temperature of mercury deposits is generally 90,160 ℃. [6]

Chen placer (mercury deposit) is a typical low temperature hydrothermal mineral, so its genesis is related to modern volcanism, but magmatic rocks related to mercury deposits have not been found around almost all the important mercury deposits in sedimentary rocks. so how did the magnificent and colorful cinnabar come into being?

There have been many disputes about the genesis of mercury deposits at home and abroad, among which there are mainly three viewpoints: sedimentation, sublimation and magmatic low-temperature hydrothermal solution. Because the chen placer in our country is the most in Guizhou and its surrounding area, let's take Guizhou as an example. Let's talk about how Chen placer was formed.

Chen placer, that is, mercuric sulphide (HgS), can be traced back to its origin, and we can infer the formation of cinnabar from the source of mercury (Hg), a rare element. Because mercury ore has the property of sedimentary genesis, the sources of sedimentary materials generally have the following two aspects:

Sources of sedimentary materials: 1 weathering and denudation of parent rocks, such as ancient metamorphic rocks, sedimentary rocks, igneous rocks and ore deposits (spots), etc., after these mercury-bearing protolith are weathered, the mercury in them is redeposited to form new mercury minerals. these more primitive mercury-bearing minerals may be the first source of mercury metal.

(2) volcanism, such as the gradual deposition of mercury in the submarine volcanic eruption species to form mercury deposits. Volcanic eruptions and volcanic rocks with mercury elements are gradually deposited and formed, and these materials may also become the source of mercury in new mercury deposit sedimentary rocks in the later stage of weathering.

But in any case, mercury is essentially a rare metal element, and its formation is closely related to geological activities such as volcanic hydrothermal action.

So why is it that the original minerals of mercury deposits are more than volcanic activities, but no magmatic rocks related to mercury deposits are found around almost all the important mercury deposits in Guizhou? We can speculate that these mercury substances have migrated and enriched, left the original area, enriched and precipitated in the new area, and finally formed mercury deposits.

According to the analysis of geologists, the formation of the cinnabar mercury deposit in Guizhou can be divided into three stages: the appearance of mercury, hydrothermal mineralization, enrichment and precipitation mineralization.

The three stages of the formation of the Chensha mercury deposit in Guizhou 1. The appearance of mercury, as a rare metal, its present world is closely related to magmatic activity. It is volcanic magmatic activity that brings mercury to the surface, and from any point of view, volcanic magmatic activity is the "mother" of almost all known metals on the surface.

2. The stage of hydrothermal mineralization according to the study of inclusions in mercury deposits by geologists, the homogeneous metallogenic temperature range of Guizhou mercury deposit is 80 ~ 200 ℃, and the main temperature data fall in the ranges of 90 ~ 100 ℃ and 145 ~ 160 ℃, and the latter is dominant. Although the mercury deposits in Guizhou are widely distributed, the temperature difference is small, with an average of about 136-167 ℃, which determines that the mercury deposits in Guizhou belong to low-temperature hydrothermal mineralization, and these hydrothermal fluids are probably a kind of low-temperature and high-salinity gas-liquid type of groundwater hydrothermal solution, which is closely related to geological activities.

On the basis of the preliminary enrichment of multi-source mercury, a large amount of heat energy is generated in the process of crustal movement, and the groundwater hydrothermal solution produced by these heat energy gradually dissolves the minerals in the surrounding rock and circulates endlessly. Under suitable physical and chemical conditions and appropriate structural conditions, mercury begins to enrich in a certain area. [7]

Correlation between Guizhou active faults and geothermal distribution [8] 3. During the Cambrian period, there was a wide range of shallow seas in southern China. Under the action of plate movement, sea water first invaded eastern Yunnan and gradually expanded to the northeast. A stable and broad shallow sea environment was formed around "Sichuan-Yunnan ancient land" and "Xuefeng ancient land". At this time, Guizhou experienced a complete transgression and retrogression cycle from morning to night.

Careful readers may have found that comparing the tectonic location map of Guizhou Province and the schematic map of the ore belt, we can find that their distribution is obviously overlapped. Cambrian long-term geological processes not only brought rich mercury to this land, but also caused transgression and retrogression. Guizhou has enriched a large amount of mercury from land sources, volcanoes and the depths of the earth's crust. At the same time, folds, faults and fissures caused by tectonic activities have also become important locations for mercury mineralization and enrichment. This is why almost all mercury ore belts, ore fields, ore deposits and even orebodies are strictly controlled by folds, faults and fractures. On the other hand, the metal element mercury dispersed in various rocks, or mercury-containing compounds and organic mercury complexes, even with gold, antimony, arsenic, lead, zinc and copper, migrate and accumulate repeatedly under appropriate geotectonic and lithofacies Palaeogeographic conditions. the mercury-rich precipitation is eroded and leached by the groundwater hydrothermal solution of deep circulation, re-enriched in favorable structural and rock assemblage, and finally formed to form a deposit. [9]

This finally explains that most of the mercury ore belts (areas) that exist in the Cambrian in Guizhou are located in the margin of the paleo-continent, in the buried trenches of the ancient sea, between submarine uplift and depression belts, and these locations are easy for all kinds of sediments to accumulate. The deposit or its most enriched area is often located in the sedimentary belt, so the paleogeological movement not only promotes the generation and enrichment of mercury. The favorable geographical conditions formed by it further promote the enrichment, deposition and mineralization of mercury in specific areas.

Schematic diagram of mercury ore tectonic domain and mercury ore belt in Guizhou

[10] the gorgeous Chinese red not only records the vicissitudes of life for hundreds of millions of years, the circulation of the sun and the moon, but also bears the history and tradition of Chinese civilization for thousands of years. This color, which absorbs the essence of heaven and earth and is still full of vitality after the vicissitudes of life, such as the rising sun, emits a charming light like the setting sun.

reference

[1] Locomotive design. There is a color that only belongs to China-- "Chinese Red". Sohu Culture (sohu.com).

Di Gu, Chen Min. Q: what is cinnabar? [J] Foreign Science and Technology Trends. 1995. (10): 63.

Baidu encyclopedia. Cinnabar (mercury sulfide mineral). (baidu.com)

[4] Chris Pellant. Rocks and Minerals: China Friendship Publishing Company, 2007

[5] Xiang Shun. Geochemistry of ore-forming fluid in the Gongguan Hg-Sb deposit, Xunyang, Shaanxi [D] China University of Geosciences (Beijing). 2020-07-16.

[6] Liu Ping. Sulfur isotopic composition of cinnabar in main mercury deposits in China [J] deposit geology. 1992, (03)

[7] Hua Yongfeng. A preliminary study on the genesis of mercury deposits in Guizhou and its adjacent areas [J] Acta Geologica Sinica. 1981, (02)

[8] Guizhou Geological Survey Institute. Discussion on the genesis of regional geothermal in Guizhou [J] Geophysical and geochemical exploration. 2022, 46 (02).

[9] Zhou Dezhong. Mercury deposits and geological structures in Guizhou [J] Geology of Guizhou. 1991, (02)

[10] Guizhou Geological Survey Institute. Characteristics of tectonic movement in Guizhou and its geological significance [J] Guizhou geology. 2013 Jol 30 (02)

This article is from the official account of Wechat: stone popular Science Studio (ID:Dr__Stone). Author: Bian Zhou

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