In terms of plate tectonics, the Chinese continent is a product of long-term and complex interaction between the Siberian, Tarim, North Chinese, Yangtze, South Chinese, Indian and Pacific paleoplates and other relatively small plates or blocks. Along the converging margins of these plates, fold zones formed as a result of plate collisions, whereas in the center of the plates, basins and plains developed because of the stable tectonic settings and sedimentation. Mineralization related to endogenic geological processes therefore normally took place in the fold zones, or mountain areas. For example, pegmatite minerals mainly occur in these fold zones associated with magmatic activity.

North China represents the main part of the North Chinese paleoplate, or the so-called North China platform. The oldest rocks in China have been found in this plate and were dated to between 3,800 and 3,500 million years ago during the Archean Age. The main part of the continent may have been consolidated during the Early Proterozoic (2,600 to 1,850 Ma) and the plate was separated from Siberian-Mongolian plate in the north and from South China plate in the south by lost oceans (the Mongolian Sea in the north, and the Paleo-Tethys in the south) during the Early Paleozoic. Marine sediments from this period dominated the plate.

The North China plate merged with the Siberian-Mongolian Continent during the Later Paleozoic, which led to the formation of the Tianshan-Yingshan Mountain zone along the northern margin and regressive depositional sequences consisting of alluvial, fluvial, coastal and shallow marine clastic and coal deposits in the center and southern margin. At the same time the Tarim micro-continent also melted into the Siberia-Mongolian plate in the west.

In the Palaeozioc period, the South China plate broke out from the Gondwanan super-continent in the southern hemisphere and drifted northward. The surface of the continent was mainly covered by shallow marine and coastal plain deposits.

During the latest Permian and Triassic periods (ca 250 to 205 Ma), the integrated continent of North China, Tarim and their continental accretions collided with the South China plate in the east and with the Paleo-Tethyan plate in the west, creating the uplift of the Kunlun-Qinling fold zone between them. The collision-associated volcanism and metamorphism caused extensive mineralization in this mountain zone and their margin belts.

From the Late Mesozoic to Early Tertiary periods (ca. 200 Ma to ca. 50 Ma), the Indian continental plate and Tethyan oceanic plate, along with several micro-plates or blocks, converged and collided with the Eurasian continent as a result of gradually northward drifting of the Indian plate. This series of tectonic movements, continuing into the present, created the crust shortening and uplifting in West China and led to the occurrences of the Himalayas, the Tibetan plateau, and the high mountain chains in Southwest China. The origins of the almost endogenic minerals, especially gemstones, in these regions are closely related to the magmatism, metamorphism and tectonics of these periods.

With the westward movement and subduction of the Pacific plate from the Late Jurassic (ca. 140-150 Ma) to the present, East China became a part of an active continental margin. The Nanling mountain belt and the NNE-SSW fractures with volcanic belts in Southeast China were mainly formed during these periods. The magmatic activity and mineralization of Eastern China are strongly controlled by the tectonics of the Circum-Pacific region. As a result of the upwards movement of the mantle, magma caused by the subduction of Pacific oceanic crust beneath the eastern China continent and the NNE-SSW folding and faulting was very active. Another important geological feature of the reason is the abundance of groundwater supplied by the high rainfall in these areas which caused a high degree of hydrothermal mineralization to occur.

Mineralization and their controlling factors

Long-term geological evolution, diverse tectonic patterns, multiple geological processes and the wide range of climates in China are all very favorable factors for various mineralizations. This explains why nearly all mineral species in the word have also been discovered in China. To date, 168 types of economic mineral deposits have been found in China. According to the characteristics of their forming settings and origin, we can divide these deposits into different kinds, i.e., endogenic, exogenic and their combined types.

The endogenic minerals were mainly formed by magmatic, volcanic and metamorphic processes. Most of minerals with high physical hardness and chemical stableness and nearly all gemstones are formed by these processes also. The formation and distribution of this kind of mineral always took place within tectonic zones. As discussed above, China developed a series of fold and fracture zones, including the Altai mountain range in the Xinjiang Uygur Autonomous Region, the Tianshan-Yanshan fold zone in NW and NE China, the Kunlun-Qinling Mountains. between North and South China, the Himalayan-Ailaoshan fold zone in Western and SW China, the Nanling fold zone in Guizhou, Guangxi, Hunan, Guangdong and Jiangxi, and Wuyishan Mountain in Fujian. In these areas, especially in the western high mountain regions, iron, chromium, lead, zinc, nickel, and copper deposits are widely found associated with basic to ultrabasic intrusions. For example, the chromite deposits in Xinjiang and Tibet and the copper-nickel ores in Gansu, Jilin and Sichuan illustrate this feature. Sapphire deposits in Changle of Shandong are regarded as originating in this manner also. Volcanic iron and lead-zinc deposits have been found in the Tianshan, Kunlun, and Qilian mountains and many locations in East China. Minerals and ore bodies formed by mineralization associated with granitic intrusions and pegmatite are also widely distributed in these fold and intrusion-developed zones. For example, there are aquamarine, tourmaline, garnet and other gem minerals, and gold, titanium, tantalum-niobium deposits in the Altai and Tianshan Mountains of Xinjiang, Emeishan Mountain in Western Sichuan, Ailaoshan Mountain in Western Yunnan, Wuyishan Mountain in South Fujian, and some locations in north Hunan.

Many mineral deposits are formed by element replacement and metamorphism within the contacting belts between magmatic intrusions and host rocks along the former continent margins. Hydrothermal processes normally play an important role in this kind of mineralization. The typical deposits formed this way range from copper-molybdenum, lead-zinc, tin, molybdenum-wolfram mineral associations to iron-copper, copper-lead-zinc, wolfram-tin-molybdenum-bismuth and other poly-metallic ore bodies. They can be in turn subdivided into porphyry-type and skarn-type ores, depending on the associations of their host rocks. Typical porphyry-type deposits are copper ore in Yulong of Tibet, copper and polymetallic deposits in Dexing of Jiangxi and in Duobaoshan of Heilongjiang. The skarn-type minerals are widely distributed in East China and South China, including iron-copper mines in Daye in Hubei, copper mines in Tongguangshan of Anhui, copper mines in Wushan and Chengmenshan of Jiangxi, polymetallic mineral mines in Yaogangxian and Shizhuyuan, and lead-zinc mines in Shuikoushan of Hunan and other locations.

Minerals and ores formed by hydrothermal activities are mainly distributed in the eastern parts of North and South China and these mineralization zones are dominated by W, Sn, Mo, Zn, Pb, Sb. Hg, Cu-bearing metal deposits and fluorite, barite, calcite and other many non-metal deposits. Most collection minerals including cinnabar, regalgar, stibnite, fluorite, calcite, barite and many other minerals in South China belong to this kind of genetic type. Their distribution is normally controlled by deep fractures and regional magmatic activities, as well as groundwater regimes. Because East and South China is situated on the margin of the Eurasian plate and is close to the subduction zone of the Pacific plate, its geothermal systems in the crust were strongly influenced by the upward movement of mantle material. As a result, these areas are concentrated with hydrothermal fluid-related minerals.

Secondary minerals or exogenic minerals are also widely formed in China, especially in eastern China. This kind of mineral is mainly originated from the oxidation and hydration of other minerals and rocks in the surface or near surface settings. Moisture and groundwater usually promote the formation of this kind of mineral. These processes may be a good explanation for the wide formation of cave calcite, aragonite and other stalactic minerals, such as hemimorphite, malachite in South and Southwest China, where a wet and hot climate prevails. The beautiful green pyromophite and yellowish mimetite found recently in lead-zinc mines of Guangxi and Guiling belong to this type of mineralization also.

Since the formation of the most minerals is mainly controlled by tectonic movements, volcanic and magmatic activities and their distribution is closely associated with the orientation of the major fold and faulting zones, we may roughly determine the ages of most mineral deposits by dating their host rocks and their tectonic settings. The following figure simply shows the general distribution and ages of the main mineral deposits of China.

Mining history

Coal carvings have been found in the ruins of the later Stone Age and their radiometric age is over 6,000 years old. They are believed to have come from the Fushun coalfield in Liaoning. The earliest copper wares found were also from the Later Stone Age in North China, and bronze was already widely used since the Shang Dynasty (16 to 11 century B.C). Archaeological studies indicate that the mining activities began at least 5,000, or more, years ago in China. From the Spring and Autumn Periods (770 to 476 BC) of the Zhou Dynasty to the Warring States Periods (475 to 221 BC) of the Zhou Dynasty, iron wares, including weapons, occurred widely in China. For example, Daye copper mines in Hubei already have a history of over 2,800 years and they are still active. The earliest Chinese literature documenting mining activities found was from those periods as well. Ruins of tin, lead, silver, gold and iron mines aged between 200 BC and 220 AC were discovered in Yunnan. Mining activities entered into a period of prosperity during the Tang Dynasty (618 to 907 AC). Cinnabar, an important pigment and Chinese traditional medicine, began to be mined in large-scale as early as 2,000 years ago.

The recent mining history of China began in the later 19th century as a result of the influences of European industrialization and the importation of modern geological and mining technology. Most important large-scale mines in China were first operated with assistance from western experts, such as the Xikuangshan Antimony Mine in Hunan, and the Wanshan Mercury Mine in Guizhou. During the early 20th century the output of Antimony, Wolfram, and tin reached the highest levels in the world. According to recent statistics, the variety of economic minerals now reache 168 types distributed throughout China in somewhat more than 20,000 locations.

The mining industry in China is regarded as the most activate in the world. By the end of 2003, there are about 10,000 state-operated medium to large-scale mines and 280,000 small township-owned and private mines in China. Most collection minerals on the international market are mainly mined from the small mines. However, the Chinese government has issued a series of policies to slow the booming mining activity and to close small mines in order to protect the environment and to reduce the death rate in mines. To date, over 10,000 small mines with backward mining methods have been closed. This trend is going to continue into the foreseeable future.

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