Long-term geological evolution, diverse tectonic patterns, multiple geological processes and wide range of climates of China are the favorable conditions for various mineralizations. This explains why nearly all mineral species of the word have also discovered in this country. Up to date, 168 types of economic mineral deposits have been found in China. According to their forming settings and origin, we can divide these deposits into different types, 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 of gemstones are formed by this process too. The formation and distributions of this kind of minerals took place always within tectonic zones. As discussed above, China developed a series of fold and fracture zones, including Altai mountain in Xinjiang Uygur Autonomous Region, the Tianshan-Yanshan fold zone in NW and NE China, the Kunlun-Qinling Mts. between North and South China, Himalayan-Ailaoshan fold zone in Western and SW China, Nanling fold zone in Guizhou, Guangxi, Hunan, Guangdong and Jianxi, and Wuyishan Mt. in Fujian. In these areas, especially in western high mountain regions, iron, chromium, lead, zinc, nickel, copper deposits are widely formed associated with basic to ultrabasic intrusions. For example, chromite deposits in Xinjiang and Tibet, copper-nickel ores in Gansu, Jilin and Sichuan. Sapphire deposits in Changle of Shandong are regarded as this origin too. Volcanic iron and lead-zinc deposits have been found in Tianshan, Kunlun, and Qilain mountains and many locations of 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, aquamarine, tourmaline, garnet and other gem minerals, and gold, titanium, tantalum-niobium deposits in Altai and Tianshan Mts. of Xinjiang, Emeishan Mt. in Western Sichuan, Ailaoshan Mt. in Western Yunnan, Wuyishan Mt. in South Fujian, and some locations of north Hunan.
Many mineral deposits are formed by element replacement and metamorphism along the contacting belts between magmatic intrusions and host rocks along the former continent margins. Hydrothermal process normally plays also an important role in this kind of mineralization. The typical deposits formed in this type of mineralization are ranging from copper-molybdenum, lead-zinc, tin, and molybdenum-wolfram mineral associations to iron-cupper, 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 types of host rocks. Typical porphyry-type deposits are copper ore in Yulong of Tibet, copper and polymetallic deposits in Dexing of Jiangxi and Duobaoshan of Heilongjiang. The skarn-type minerals are widely distributed in East China and South China, including iron- copper mines of Daye, Hubei, copper mines in Tongguangshan of Anhui, copper mines in Wushan and Chengmenshan of Jiangxi, polymetallic mineral mine in Yiaogangxian and Shizhuyuan, lead-zinc mine in Shuikoushan of Hunan and other locations.
Minerals and ores formed by hydrothermal activities are mainly distributed in 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 of 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 the groundwater regimes. Because East and South China is situated on the margin of Eurasian plate and closed to the subduction zone of the Pacific plate, its geothermal systems in the crust were strongly influenced by the upward movement of mantel material. As a result, these areas are concentrated with hydrothermal fluid-related minerals.More discussion and description will deal with in other places of this book.
Secondary minerals or exogenic minerals are also widely formed in China, especially in eastern China. This kind of minerals is mainly originated from the oxidation and hydration of the other minerals and rocks in the surface or near surface settings. Moisture and groundwater usually promote the formation of this kind of minerals. It may be a good explanation for the wide formation of cave calcite, aragonite and other stalactic minerals, such as hemimorphite, malachite in the South and Southwest China, where the 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 too.
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 the 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.