8.1.1 Overview of metallogenic regularity

Metallogenic regularity is actually a science to study the occurrence, development, evolution, enrichment and dispersion of ore deposits and their relationship with related controlling factors. If it is discussed in detail, its content is very huge, and the most important ones are summarized as follows:

8.1.1.1 Metallogenic specificity of geotectonics

The occurrence, development and evolution of mineral deposits in Tarim continental plate mainly depend on the formation and evolution of Tarim plate. In the stage of paleo-continental core and continental crust, ore-forming elements such as Cr, Ni, Co, V, Cu, Fe and Mn were gathered due to the differentiation of mantle-derived materials in the pan-oceanic stage. Some of them formed large-scale deposits, while others gathered ore-forming source beds, which prepared the material foundation for subsequent mineralization. In Proterozoic, oxygen gradually formed and its content increased, and oxidation played an increasingly important role, gradually developing ferrosilicon formation and related mineralization of Fe, Cu, Mn and Au. In the late Neoproterozoic, the basement of Tarim continental plate was cast, and the plate edge entered the tectonic metallogenic environment of active continental margin, accumulating volcanic rocks and intrusive magmatic arcs and metal deposits, such as porphyry copper-molybdenum ore, black ore and yellow ore. Oil, natural gas, sandstone copper deposits, carbonate lead-zinc deposits and other minerals were formed in the intracontinental basin and back-arc basin in the relatively stable area of the plate. When the plate structure entered the intracontinental stage, the northern margin of the Tarim plate collided with the Kazakhstan-Junggar plate in Carboniferous, and * * * became a part of the Eurasian plate. After the Paleogene and the NeoTethys oceanic plate were stitched together, the whole region entered the intracontinental tectonic metallogenic environment, and then developed the inland basin metallogenic series and the continental hotspot metallogenic series.

8.1.1.2 Metallogenic specificity of magmatic activity

The specific magmatic activity is produced in a specific tectonic environment, and the specific magmatic activity breeds a certain deposit and deposit combination, which is the metallogenic specificity of magmatic activity. This research and summary has a history of nearly a hundred years. In recent years, due to the involvement of plate tectonics, it has added a new aspect, which is very different from the Christmas tree model of Emmons and Ringelman. For example, mafic rocks and ultramafic rocks in the tectonic environment of cracking and subduction collision have different metallogenic specificity. Porphyry deposits in the magmatic arc on the active continental margin have great prospecting potential. Xinjiang has been adhering to this belief for a long time, extending the Balkhash Lake porphyry copper metallogenic belt in the ancient Asian metallogenic domain to the eastern Tianshan area, and extending the Kalmakel porphyry copper metallogenic belt to the Tielekutan area in Kuqa County. It will also connect the Yulong porphyry copper metallogenic belt in Tethys metallogenic domain with the Shimei porphyry copper metallogenic belt in Salce through Yunwuling and Xiruo copper mineralization clues. Non-orogenic alkaline granite in plate relaxation stage also has obvious restriction on tin-tungsten ore and rare earth metal ore.

8.1.1.3 Metallogenic specificity of lithofacies palaeogeography

The formation and evolution of many deposits in Tarim and its surrounding areas are closely related to the lithofacies palaeogeography environment, such as sandstone-type copper deposits, marls and impure limestone-type ferromanganese deposits and carbonate-type lead-zinc deposits, which generally range from continental margin clastic rocks to impure limestone in coastal shallow sea to shallow sea-semi-deep sea limestone in marginal sea basins, and they often have certain rock zoning for mineralization.

8.1.1.4 Metallogenic specificity of metamorphism and metamorphic facies

The deep metamorphic facies of regional metamorphism often controls the mica and rare metal deposits of migmatite type and granite pegmatite type, the deep metamorphism of calcareous surrounding rocks controls the phlogopite and corundum deposits, and the deep metamorphism of sandy argillaceous surrounding rocks with high aluminum content controls the corundum and high aluminum raw material deposits. A specific deposit has a set of matching alteration models of ore-forming surrounding rocks, which in turn can be used to find specific deposits, such as skarn-type iron-copper deposit alteration model, porphyry deposit alteration zoning model, epithermal precious metal deposit alteration model, hot spring-type mercury deposit alteration model and so on.

8.1.1.5 The proposition of ore-controlling theory of tectonic boundary

has a long history, and different scholars have demonstrated this proposition from their own reality. For example, plate edge ore control theory, deep fault ore control theory, ductile shear zone ore control theory, expansive structure ore control theory, nappe structure ore control theory, volcanic basin boundary ore control theory, sedimentary basin edge ore control theory, spanning structure ore control theory, anti-Tianshan structure ore control theory (Wang Xuechao, 1996) and network structure ore control theory (with special emphasis on the great role of network intersection points in ore control and metallogenic prediction) and so on. The Tarim continental plate is so vast that the above ore-controlling theory always has suitable deposits in different time domain, space domain and material domain. In recent 2 years, we have used these arguments to varying degrees in studying metallogenic regularity and making metallogenic prediction.

8.1.1.6 "Ancient pregnancy and new formation" theory

This is an important concept to study the regional mineralization and metallogenic regularity, which means that the initial conditions of the deposit (such as material source, migration, structural conditions and medium conditions of enriched ore) were bred long before the formation of the deposit, and the industrial deposit was formed at a relatively late stage. Chi Sanchuan put forward the stage development theory of mineralization concentration area and mineralization by demonstrating the copper series in western Sichuan. Rui Xingjian put forward the concept of "ancient pregnancy and new formation" through the whole process of dispersion, enrichment and accumulation of copper in northeast Jiangxi and Xinjiang basin, and supported the conclusion that the mineralization concentration area in Chisanchuan and various types of copper deposits were formed in multiple stages. Later, he further studied the gold deposits in Shandong Province. Although the mineralization age was very late (after Yanshan period), it was inextricably linked with the ore source bed and ore germ bed of pre-Sinian. In recent years, when I worked in Xinjiang, especially in Tarim area, I further realized the importance of ancient pregnancy and new mineralization. For example, in the northwest of Tarim, the background of copper-containing elements is relatively high. Proterozoic Muzhaerte Group is widely distributed, and formed Ahekulang and Artes copper, gold, iron and copper deposits and occurrences. In Devonian-Carboniferous, sedimentary-volcanic stratabound and porphyry copper deposits and occurrences appeared, and in Neogene, Sabuha copper deposits appeared, which are in the same strain. Usually, it is ancient pregnancy and new formation, which is restricted by the same geochemical province or the same mineralization concentration area.

8.1.1.7 "Deep source and shallow formation" theory

It plays a particularly important role in the study of metallogenic prognosis of Tarim continental plate. As the name implies, the ore-forming materials originate from the deep crust and often reach the mantle or lower crust, while the deposit is located very shallow, in the upper crust and even close to the surface. The most common deep-seated epithermal deposits are porphyry deposits, and other volcanic pipeline deposits, such as kimberlite-K-Mg lamprophyre type diamond deposits, ultraalkaline rock type rare earth metal deposits, and alkaline ultrabasic-basic complex type vanadium-titanium iron deposits, should also belong to this category. During the formation and development of Tarim continental plate, a lot of deep-seated materials were added, especially after Permian, the crust consolidated and its stability was strengthened, but the deep faults developed or revived later opened up new space for the activities of mantle hot spots or heat flow columns. At present, the discovery of the Palaeo-Asian porphyry copper belt in the East Tianshan Mountains, the exploration of the Karakorum-Muzittagetis porphyry copper belt, the emergence of a large number of diamond prospecting clues, the huge amount of vanadium-titanium magnetite, and the gratifying prospecting prospects of alkaline rocks, alkaline pegmatites and alkaline ultrabasic rocks will promote the research of "deep-sourced epithermal" deposits to a new level.

8.1.2 tectonic metallogenic stage and environment

most researchers believe that tectonic environment is the dominant factor restricting mineralization. In 1981, A, H, G, Mitchell, M, S and Gassen summarized 4 tectonic metallogenic environments of the plate from the study of the relationship between plate structure and regional metallogenic conditions. Each tectonic metallogenic environment has more than one genetic type of deposits. Based on this understanding, through the study of the relationship between tectonic evolution of Tarim continental plate and metallogenic environment, four tectonic metallogenic stages and ten tectonic metallogenic environments can be roughly divided (Figure 8-1). ]

[, Figure 8-1 Schematic diagram of tectonic metallogenic environment of Tarim continental plate

Fig.8-1 Evolution of metallic environment in tarim block

1—Upper mantle; 2-oceanic crust; 3-small rock mass; 4-Paleocontinental core; 5-continental crust; 6-marine sediments; 7-continental sediments; 8— subduction zone and notes (same as conventional); Notes on metal deposits; Notes on structural parts: Q— Qinghai-Tibet Plateau; Ta-Tarim basin; Te-Tianshan Mountains; TT-Tethyan oceanic crust plate; Ka-Kawabulak Neoproterozoic suture zone; A-Aqike Kuduke Late Paleozoic suture zone; K-Kanggurtag Late Paleozoic suture zone; Z-Junggar oceanic crust plate; Tz-Middle Paleozoic continental core in Tazhong; Tb-Tarim continental crust

8.1.2.1 Early Archean-Neoproterozoic tectonic metallogenic stage.

The minerals in this stage are mainly Cr, Ni, Co, V, Fe, Mn, Cu, Au deposits in the supracrustal rock series, as well as the newly formed banded magnetite, greenstone type gold and copper deposits, fractured altered rock type gold deposits and conglomerate type gold deposits, etc. The resource prospect is particularly huge, and the work in this area is still in its infancy. Including:

(1) Archean-Proterozoic supracrustal rock series dominated crystalline basement tectonic metallogenic environment (ⅰ);

(2) Metallogenic environment of metamorphic basement composed of Neoproterozoic volcanic eruption and terrigenous clastic rocks (Ⅱ).

8.1.2. Late Paleozoic-Late Paleozoic tectonic metallogenic stage in 2 yuan.

It includes stable cratonization deposits of Tarim continental crust plate from Sinian to late Paleozoic, active deposits of continental crust edge and ocean-land transition zone, and intracontinental pull-up deposits of Xiaoyang basin. Include:

(1) stable sedimentary tectonic metallogenic environment of continental crust craton (ⅲ). Distributed in the main areas of Tarim continental crust, the sediments are mainly clastic rocks and carbonate rocks with stable deposition, which is a favorable environment for the formation and storage of oil and natural gas.

(2) Tectonic metallogenic environment in the transitional zone between ocean and land (Ⅳ). In Paleozoic, the northern margin of Tarim plate was adjacent to the Kazakhstan-Junggar oceanic crust, and the southern part was connected with the Qin-Qi-Kun finite small ocean basin (Paleotethys Ocean). The northern part experienced three collision accretions in Sinian, Early Paleozoic and Late Paleozoic, and Wusun Mountain and Sa armin cracked twice, forming a series of minerals related to island arc collision. The southern margin has undergone many times of cracking, collision and proliferation in Kogan, Kudi, Zaiyileke and Yesanggang, forming a series of minerals related to plate marginal activities.

(3) rift tectonic metallogenic environment (ⅴ). Since the formation of Tarim continental crust plate, Kuluktak-Mangar aulacogen has been produced in the late Proterozoic-Paleozoic, Beishan Rift and Kungaishan Rift have been produced in Carboniferous, and a series of minerals related to rift structures have been formed. Such as bimodal volcanic massive sulfide copper ore.

8.1.2.3 late Paleozoic-early and middle Cenozoic tectonic metallogenic stage.

The starting and ending times of different sections are slightly different, generally starting from the Late Carboniferous or Early Permian and ending in the Late Cretaceous or Paleogene. Tarim and its northern margin are the intraplate tectonic metallogenic environment of ancient Eurasia. The southern margin of Tarim continental plate is the tectonic metallogenic environment of the transition zone between Tarim continental plate and Tethys oceanic crust. Including:

(1) Mesozoic plate-inland sedimentary basin tectonic metallogenic environment (ⅵ). Mainly in the tectonic environment of plate inland sedimentary basin, the main minerals are oil, natural gas, coal, in-situ leachable sandstone-type uranium deposits, salts, gypsum, saltpeter, celestite, lithium, boron and Sabha-type copper, lead, zinc, manganese ore and so on.

(2) continental hot spots, mantle plume and non-orogenic tectonic metallogenic environment (ⅶ). This tectonic metallogenic environment may have started from the middle of Variscan, and it was most developed in the late West China and Indosinian, and it still appeared in the Tethys tectonic belt in Holocene. The main minerals are metallogenic series related to mantle plume, such as vanadium-titanium magnetite, porphyry copper ore, alkaline rare metal rare earth metal ore, diamond ore, gem and cast stone ore related to continental basalt, etc.

(3) Tectonic metallogenic environment of Mesozoic-Cenozoic ocean-land transition zone in the northern margin of Tethys Ocean (Ⅷ). The tectonic belt is dominated by Triassic turbidite, Jurassic and Cretaceous pyroclastic rocks and lava, and there are Paleogene marine volcanic eruption rock series in Bangongcuo area in northern Tibet. The main minerals are sulfide copper deposits related to marine basic volcanic lava, Tethys porphyry copper deposits and volcanic iron deposits.

8.1.2.4 Early Cenozoic-modern tectonic metallogenic stage.

Due to the closure and extinction of the Tethys (Alps-Himalayas) Ocean, a unified Eurasia was finally formed, and only the Mediterranean Sea remained in the Tethys Ocean. Enter the stage of intraplate tectonic activity.

(1) Tectonic metallogenic environment of Mesozoic-Cenozoic plate-inland facies sedimentary basin (ⅸ). It evolved from the same tectonic metallogenic environment (ⅵ) in the previous stage. The main metallogenic characteristics are similar, but the intensity and breadth of coal mineralization have decreased, while the metallogenic activities of evaporite minerals and in-situ leachable sandstone-type uranium deposits have been strengthened.

(2) Tectonic metallogenic environment of continental hotspots and non-orogenic magmatic belts in the northern margin of Tethys (X). According to the available data, after the Indosinian Movement, the activities of non-orogenic intrusive rocks and continental hotspots in Tarim and Tianshan areas declined, and no intrusive rocks have been found since Yanshan period. On the other hand, in Kunlun Mountain and Karakorum Mountain, there are a large number of intrusive rocks and small bedrock exposed in Yanshanian and Himalayan periods, and continental basalts in Himalayan period are common. The last magmatic eruption occurred in 1951. The main minerals may be porphyry copper, porphyry tungsten-tin and basalt sapphire.

8.1.3 Metallogenic series and expected ore deposit model

If a large, relatively independent and internally related geological tectonic mineralization process is regarded as a metallogenic series, then the gestation, development and evolution of Tarim plate and a series of minerals related to it belong to the same metallogenic series.

according to the evolution process of tectonic mineralization, Tarim continental plate metallogenic series can be divided into five metallogenic subsequences: continental plate basement tectonic layer metallogenic subsequence, continental plate marginal active zone metallogenic subsequence, continental plate cratonic depression metallogenic subsequence, continental plate continental sedimentary caprock metallogenic subsequence, continental hot spot and mantle heat flow column metallogenic subsequence. About 5 representative metallogenic models have appeared or are predicted to appear. Among them, some metallogenic models have examples of mineral deposits in this area, and their resource prospects have reached large and extra-large scales, such as oil, natural gas, coal, potassium salt, copper and gold, etc., and the prospecting situation of in-situ leachable sandstone-type uranium deposits is also very good; The prospecting prospect of some metallogenic models is not clear, especially the minerals in the basement structural layer of continental plate. With the in-depth development of investigation and research work, a major breakthrough will be made.

see table 8-1 for the metallogenic series of Tarim continental plate.

Table 8-1 Brief Table of Metallogenic Series of Tarim Continental Plate

8.1.4 Four-dimensional Model of Regional Metallogenic Circles and Piercing Assemblies of Tarim Plate

The tectonic evolution of Tarim Continental Plate has a long time, many stages, a wide geographical area, many kinds of minerals and complex forms, and the metallogenic models of a single deposit are numerous and complicated. So what are the laws and characteristics of the spatial and temporal allocation of minerals in Tarim region? We have expressed our opinions on the stratigraphic circle combination and piercing combination of the Tarim plate metallogenic system. It is further discussed as follows.

8.1.4.1 Layered combination

The basement structural layer, sedimentary cover and intra-plate facies sedimentary layer of Tarim plate have obvious layering. Archean and Proterozoic