Division of gold metallogenic areas (belts) in Jiaodong area

The division of metallogenic belt is an objective response to the understanding of metallogenic regularity of mineral deposits, and it is also an important basis for determining the prospecting direction of mineral resources and the strategic deployment of exploration work. At present, the classification system of ore-forming areas (zones) arranged in sequence is widely used in China, and the five-point method is often used, namely, ore-forming areas (grade I ore-forming areas), ore-forming areas (grade II ore-forming areas), ore-forming areas (grade III ore-forming areas), ore-forming areas (grade IV ore-forming areas) and ore fields (grade V ore-forming areas).

In the distribution area of gold deposits in Jiaodong, I-grade metallogenic belt generally belongs to coastal Pacific metallogenic domain, II-grade metallogenic belt belongs to North China landmass metallogenic province, and III-grade metallogenic belt belongs to Jiaoliao metallogenic area (Chen Yuchuan,1999; Liu Yuqiang et al., 2002), the grade ⅳ metallogenic belt belongs to Jiaobei metallogenic subregion (Jiaobei gold deposit concentration area). Because the distribution of gold deposits in Jiaodong area is strictly controlled by structure and has the characteristics of concentrated zoning and banded distribution, it is difficult to reflect its regularity only by dividing the grade V metallogenic belt. Therefore, in this paper, the ore field is reduced to grade VII unit, and two ore belts (corresponding to grade VI) and metallogenic areas (corresponding to grade V) are added on it. This paper focuses on the division of grade ⅴ ~ ⅶ metallogenic belts.

There are many studies on the division of gold metallogenic belts in Jiaodong, which are generally divided into Zhaoyuan-Laizhou-Changyi metallogenic belt, Qixia-Daotou-Pingdu metallogenic belt, Mu Ping-Rushan metallogenic belt, Weihai-Wendeng metallogenic belt and Taocun-Haiyang-Laiyang metallogenic belt (Wang Shicheng et al., 2003). This division takes into account the regional distribution of gold deposits, magmatic rocks, structures, geophysical and geochemical anomalies, heavy sand anomalies and other comprehensive information characteristics. By studying the main ore-controlling faults of altered rock-type gold deposits in Jiaojia fault zone, the Sixth Geological Team of Shandong Province summarized the spatial distribution characteristics of the fault system and put forward the understanding of multi-level structural ore-controlling and large-scale structural mineralization (Li Hongji, 1996). It can be seen that Shandong gold deposit is obviously controlled by structure. Therefore, this book mainly divides V ~ VII gold metallogenic belts according to the spatial distribution law of gold deposits, ore-controlling structures of faults, ore-controlling geological bodies and deposit types (Figure 3- 1).

I. Mineralized communities in northwest Jiao Jiao

Located in the northwest of Jiaobei uplift, it is adjacent to Zhaoping fault zone in the east, Sanshandao fault zone in the west, Longlai fault zone in the north and Pingdu fault zone in the south. Metallogenic communities are generally distributed along the NE direction, with a length of 100km, a width of 60km and an area of about 6000km2.

The exposed area of magmatic rocks in the area accounts for more than 80% of the bedrock area. In addition to Qixia gneiss suite exposed in Zhaoyuan City and southern Laizhou City, the main rocks are Linglong adamellite and guojialing granodiorite, which are closely related to gold deposits. Stratigraphically, Fenzishan Group and Jingshan Group are distributed in the southwest of the metallogenic community, except for a few Cretaceous outcrops in the south. The structure in the metallogenic belt is developed, with NE, NNE, NW and near EW faults. NE-trending and NE-trending faults are the main ore-controlling structures. Sanshandao, Jiaojia and Zhaoping fault zones constitute the basic structural framework of this area.

The community is rich in gold resources, and the proven gold resources account for more than 90% of the total reserves in the whole Jiaodong area. There are 28 medium-sized and above gold deposits, and all super-large gold deposits in Jiaodong area are produced in this metallogenic belt. The types of gold deposits in this area are mainly altered rock type (Jiaojia type) and chronological vein type (Linglong type), which are obviously controlled by magmatic rocks and NE-trending structures. Most of the gold deposits are distributed in the edge of rock mass, the NE-trending main structural belt and the secondary faults in its footwall. This community consists of three main gold belts.

(1) sanshandao gold belt

Located in the control range of Sanshandao fault zone, the extension range of the fault to both ends is inferred. The fault is located on the Sanshan Island-Cangshang line along the Bohai Sea. After exploration, the total length is 12km, and both ends extend into the Bohai Sea. It developed in the contact zone between Linglong granite and Qixia gneiss. There is strong sericitization alteration along the fault zone, and there are vein-like industrial ore bodies as long as 100 meters to more than 1000 meters. Ore bodies occur in granite structural breccia and cataclastic rocks protruding to the northwest on the fault surface and the footwall of fault gouge. From north to south, there are three altered rock-type gold deposits in Sanshandao, Xinli and Cangshang, which constitute Sanshandao gold field.

Figure 3- 1 division of gold mineralization zone in Jiaodong area

(2) Jiaojia gold belt

The control range of Jiaojia fault zone (including the range inferred to extend to the southwest) is bounded by Jiaojia fault zone (Gaojiazhuang-Xincheng-Jiaojia-Sizhuang-Ziluojijia) in the west, Songjia-Jinling line in the east, northeast-Huangshanguan fault zone in the northern section of Longlai fault zone in the north, and the southwest until it is inferred that Jiaojia fault zone may extend to the southwest. The ore belt includes Jiaojiazhu fault and branch fault, as well as several gold deposits and gold spots controlled by Lingbei fault zone in the Jiaojia fault and footwall of fault zone in Mazhuang-Wangjiazhuang area. Large, medium and small gold deposits such as Jiaojia, Xincheng, Hexi, Hedong, Dongji, Longbu, Matang, Shangzhuang, Wangershan and Sizhuang are controlled by Jiaojiazhu fault and its branches. Small and medium-sized gold deposits such as Qiansunjia, Lingshangou, Bushang, Yuantuan, Huangbuling, Jiangjia, Weijiagou, Beijie and Bunan are controlled by Lingbei fault zone. The fault zone in Mazhuang-Wangjiazhuang area controls Anshi small-scale gold deposits and many gold spots. In the distribution areas of Jingshan Group in Shibu Town and Zhangshe Town in northern Pingdu, the Great Zhuangzi Gold Mine (also known as Black yangshan Gold Mine) and Jigau Zhuang Gold Mine were discovered at the end of the 20th century. The gold deposits in this area are obviously controlled by a series of NE-trending or NE-trending fault zones such as Zhuangzi, Paolo, Zhangshe-Magezhuang, Dong Shiling-Qian Lou and Jigau Zhuang. However, due to the large coverage area in Quaternary, the scale and combination law of faults are unclear, and it is speculated that it may be the south extension of Jiaojia fault zone.

Jiaojia gold belt includes four gold fields: Jiaojia gold field controlled by Jiaozhujia fault and its branch faults, Lingbei gold field controlled by Lingbei fault, Anshi gold field south of Huangguanguan fault, and Greater Zhuangzi-Jigau Zhuang gold field controlled by a series of NE-trending or NE-trending fault zones such as Great Zhuangzi fault, Paul fault, Zhangshe-Magezhuang fault, Dong Shiling-Qian Lou fault and Jigau Zhuang fault zone.

(3) Zhaoping gold belt

It is bounded by Zhaoping main fault in the east, Songjia-Jinling-Xiaqiu-Pingdu line in the west, Huangshanguan fault in the northeast as the north, and Pingdu fault in the east-west as the south. Including Zhaoping main fault and its footwall secondary fault, Zhaoping main fault controls super-large and medium-sized altered rock-type gold deposits such as Taitai, Toutou, Dayinggezhuang, Dalang, Caojiawa, Jiang Jiayao and Xiadian. The Linglong secondary fault zone in the footwall of the Qing member of Baotou, the main fault in Zhaoping, controls the super-large, medium-sized and small-sized gold deposits in time-related veins such as Dongfeng, Dachaitou No.52, Linglong 108, Jiuqu, Dongshan 10, Dongshan 175 and Ding Shuang. The secondary faults in the footwall of the southern section of Zhaoping main fault control Jianli, Jiudian and Shangzhuang small gold deposits.

Zhaoping gold belt includes three gold fields: Linglong gold field controlled by Putouqing fault in the north of Zhaoping fault and its footwall secondary fault, Dayinggezhuang-Xiadian gold field in the middle and Jiudian gold field in the south footwall of Zhaoping fault.

Second, Peng Qi Fucheng mining community

Located in the middle of Jiaobei uplift, it contains Qixia-Daliuhang gold belt, starting from Penglai Wulipu fault and cliff fault in the west, Bajiao-Zhongqiao fault in the east (extending to Dujiaya fault in the east), taking the northern boundary of Jiaolai sag as the line in the south and the coastline in the north. Qipeng Fucheng mining area is generally rectangular, extending in northeast direction, with a length of about 65km and an average width of 38km, with a total area of about 2470km2.

Magmatic rocks are developed in Daliuhang area in the north of the residential area, mainly composed of guojialing granodiorite and double-roof gneiss with Cishan rock mass. Penglai Group and Qingshan Group are exposed in Zangjiazhuang and Xiangkuang areas in the middle, and TTG rock series is developed in Qixia area in the south. The structures in this area are dominated by NE and NW directions, ductile shear and interlayer sliding structures are developed, and the scale of fault zone is generally small.

The gold deposits in this area are mainly time-pulse-type, with a small number of interlayer stripping zones. There are many deposits, but the scale is generally small, mainly ore occurrences and mineralization points. Only a few deposits, such as Zhangjia, Taiqian, Majiayao, Dujiaya and Heilangou, have reached or approached medium and large deposits.

Qixia-Daliuhang gold belt includes Qixia gold field and Daliuhang gold field.

Three. Mouru metallogenic community

Located at the junction of the eastern margin of Jiaobei block and Weihai-Rizhao magmatic active belt, including the eastern margin of Jiaobei uplift and the northeastern margin of Jiaolai basin. It starts from Taocun fault in the west, to the east of Jinniushan fault zone (or Kunyushan granite body), to the northeast edge of Jiaolai basin in the south and to the seaside in the north. It is about 60 kilometers long, 50 kilometers wide from east to west and covers an area of 3,000 square kilometers.

Linglong granite Kunyushan rock mass is mainly distributed in the east of residential area, and the strata in the west are widely exposed, mainly Proterozoic Jingshan Group and Cretaceous strata, with a small amount of Neoarchean Jiaodong Group. Mesozoic granitoid intrusions are scattered all over the place. The structure is dominated by NE and NNE faults, and Taocun fault zone and its derived structures and Jinniushan fault are the main ore-controlling structures.

The structure in this area is complex, and there are many types of gold deposits, mainly of time-dependent pulse type, as well as altered rock type, altered conglomerate type and interlayer detachment zone type in fracture zone. The gold deposit is controlled by steep-dip fault structure and gentle-dip detachment zone. According to the different ore-controlling structures, it is divided into two gold belts.

(I) Taocun Gold Belt

It is distributed in Taocun and Laishan areas, and the distribution range is basically consistent with the control range of Taocun fault zone. Taocun fault in the west, Haiyang fault in the east and seaside in the north. The northeast edge of Jiaolai basin is its southern boundary.

There are both time-pulse type gold deposits and altered rock type gold deposits in this area, with many occurrences and generally small scale. Only Pengjia Mine is close to medium-sized gold deposits.

Taocun gold belt includes Laishan-Shirley Wang Zhuang gold field and Pengjiakuang gold field.

(2) Muru gold belt

It is distributed in Muping and Rushan areas, and the distribution range is basically consistent with the control range of Jinniushan fault zone. The northern boundary of Kunyushan rock mass is the north boundary, and the Xinhe-Zetou east-west fault is the south boundary.

Most of the gold deposits in this area are of gold-bearing sulfide time-pulse type, which are mainly controlled by Kunyushan rock mass and Jinniushan fault zone. With Jinniushan fault as the center, gold deposits are densely developed, and there are three large gold deposits: Jinqingding, Jinniushan and Denggezhuang.

Muru gold ore belt includes Denggezhuang-Jinqingding gold ore field.