Dapai mining area is a large-scale deposit dominated by lead-zinc ore, accompanied by polymetallic minerals such as iron, manganese, silver, copper and molybdenum. It is located in the middle of Yong 'an-Mei (county) Upper Paleozoic depression zone, on the west side of Zhenghe-Dabu deep fault zone, and in Datian-Longyan secondary depression in southwest Fujian depression zone. Southwest Fujian, where it is located, is a typical area where the east-west structure of Tethys and the northeast structure of the Asian continental margin around the Pacific Ocean alternate in time and space. It is the main body of Yong 'an-Mei 'an-Huichang polymetallic metallogenic belt and an important metallogenic concentration area in southeastern China. The developed deposits in the area include Makeng super-large iron mine, Zijinshan super-large gold mine, Yangshan iron mine and Yanbei tin mine.

2. Geological characteristics of ore bodies

Lead-zinc ore bodies mainly occur in the fracture zone composed of fractured marble, siliceous rocks, skarn and mylonite in the middle and upper part of Qixia Formation of Lower Permian. Qixia Formation is a set of carbonate deposits in shallow sea. Due to strong metamorphism, most rocks have been metamorphic to marble and skarn, which are the main occurrence horizons of lead-zinc mines in the mining area. The ore body is controlled by the fracture zone and is layered, quasi-layered and lenticular (Figure 1-7). 42 lead-zinc ore bodies have been delineated in the mining area, including 35 sulfide lead-zinc ore bodies and 7 independent oxide lead-zinc ore bodies. Among the identified reserves of lead and zinc resources in the whole region, lead and zinc sulfide accounts for 86.05%, and lead and zinc oxide accounts for 13.95%. In addition, 9 magnetite bodies, 8 molybdenum bodies, 5 copper bodies and 1 silver body are delineated in the mining area.

Figure 1-7 Geological Profile of Dapai Pb-Zn Polymetallic Deposit in Yongding County, Fujian Province

(According to Xu Naizheng et al., 2008)

1-Quaternary residual; 2- Late Yanshanian granodiorite porphyry; 3- Lead-zinc sulfide ore; 4- lead-zinc oxide; 5- copper molybdenum sulfide; 6— Stratigraphic boundary; 7— Faults and their number; 8— Tectonic fracture zone; 9- Lower Permian Wenbishan Formation; 10- Lower Permian Shack Formation

According to field observation and microscopic identification, Dapai lead-zinc mine can be divided into lead-zinc sulfide mine, oxide mine and iron mine according to ore composition. Lead-zinc sulfide ore is mainly authigenic-semi-authigenic-irregular granular structure. Microscopically, vein structure, sharp horn structure, metasomatic residual structure, inclusion structure, edge grinding structure, opacification-directional opacification structure can be seen. The ore structures are mainly massive (massive), banded, layered and disseminated; The main metal minerals are galena, sphalerite, chalcopyrite, molybdenite and magnetite, followed by pyrite. Gangue minerals include diopside, quartz, chlorite and calcite. The oxidized ore is mainly of semi-automorphic-heteromorphic granular structure, and the radial structure and metasomatic pseudostructure can be seen under the microscope. The ore structure is mainly earthy, massive and breccia; The metal minerals are pyrolusite, galena and limonite, followed by pyrite, galena, lead alum, heteropolar ore, pyrolusite and pyrolusite. Gangue minerals include chalcedony-microcrystalline quartz, green kaolinite, kaolinite and fluorite. Iron ore is mainly semi-autogenous granular structure, followed by autogenous and irregular structure. Microscopically, vein structure, sharp horn structure, metasomatic residual structure and inclusion structure can be seen. Ore structures include massive structures, variegated structures, disseminated structures, banded structures and layered structures. The main metal mineral is magnetite, accompanied by a small amount of hematite, spinel and siderite. Gangue minerals mainly include garnet, diopside, hypodiopside, calcite, phlogopite, chlorite and Yingshi.

3. Genetic model

Based on the analysis of the metallogenic background, geological characteristics of the mining area, deposit characteristics, ore distribution characteristics, ore and surrounding rock structure and mineralization, it is considered that Dapai Pb-Zn polymetallic deposit mainly belongs to stratabound skarn deposit, and the mineralization has gone through sedimentary period, metamorphic hydrothermal period, magmatic hydrothermal period and supergene weathering and leaching period. As a typical skarn deposit, mineralization is mainly controlled by structure, strata and magmatic rocks. In terms of structural ore control, the shape of ore body is obviously controlled by a series of imbricate thrust faults and interlayer faults (fracture zones) with different scales and southeast strike in the shallow fold-thrust nappe structural system. In the aspect of stratigraphic ore control, the ore body occurs in a certain horizon, that is, the Upper Carboniferous Chuanshe Formation and the Lower Permian Qixia Formation. Formation rocks are mainly carbonate rocks, including calcareous mudstone, tuffaceous fine clastic rock and tuffaceous siliceous mudstone. , it is easy to break and occupy. In terms of magmatic ore-control, the main magmatic rock in the area is the late Yanshanian monzoporphyry, which provides polymetallic ore-forming hydrothermal solution and activates, superimposes, migrates and enriches iron, lead and zinc polymetallic in sedimentary media.

4. Brief introduction of mineral deposit series specimens

In 20 12, after in-depth study on the geological characteristics and rock types of lead-zinc polymetallic deposits in dapai mining area, Yongding county, Fujian province, 20 samples were collected by mining area sorting method (table 1-3), which were mainly divided into three types: ore, surrounding rock and rock. Among them, 8 ore samples were collected, and the lithology was mainly chalcopyrite, lead-zinc sulfide, copper-lead-zinc sulfide, manganese-lead-zinc oxide, magnetite, chalcopyrite and chalcopyrite. Eight surrounding rock samples were collected, and the lithology was mainly marble, siliceous rock, carbonaceous siltstone, limestone, ferrimagnetite diabase, garnet diopside skarn, siltstone and skarnized marble. Four rock samples were collected, and the lithology is mainly adamellite porphyry, strongly silicified granite porphyry, medium-fine adamellite porphyry and granodiorite porphyry. The samples collected this time cover different ore samples, stratigraphic samples, roof surrounding rocks and rock sample types of lead-zinc polymetallic ore in Dapai mining area, which basically reflects the geological characteristics and metallogenic background of lead-zinc polymetallic ore.

Table 1-3 samples of lead-zinc polymetallic ore in dapai mining area, Yongding county, Fujian province

sequential

Note: In the table, PbZn3-B represents the lead-zinc polymetallic ore sample in Dapai mining area, Yongding County, Fujian Province, PbZn3-b represents the sample flake number, and PbZn3-g represents the sample flake number.

Step 5 plate

(1) Specimen photos and their characteristics description

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B0 1

Brass pyrite ore. Ore is yellow-green, with irregular granular texture and variegated texture. Ore minerals are mainly pyrite and a small amount of chalcopyrite. Pyrite is yellow-green, irregular and granular, with a particle size of 1 ~ 3 mm and a content of about 20%. Chalcopyrite, copper yellow, irregular granular and dispersed. Gangue minerals are mainly timely and diopside, with a small amount of chlorite, mica and diopside.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B02

Lead-zinc sulfide ore. The ore is variegated in gray-green, yellow-green, gray-black, white, semi-autotype-autotype granular structure, banded and variegated structure. The main mineral is galena, followed by sphalerite and chalcopyrite. Galena is lead-gray, semi-autotype-autotype granular, with a particle size of 3 ~ 20 mm and well-developed cleavage, with a content of about 10%. Sphalerite, dark gray, small amount. Chalcopyrite, copper yellow, massive distribution. Gangue minerals include diopside, Yingshi and calcite.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B03

Copper sulfide lead-zinc mine. The ore is grayish green and grayish black, with irregular granular structure and variegated structure. The main mineral is sphalerite, followed by chalcopyrite, galena and pyrite. Sphalerite, black-gray-black, irregular granular structure, particle size 1 ~ 4 mm, content 15%. Chalcopyrite, copper yellow, with oxidized surface of ochre, irregular granular structure and particle size of 0.5 ~ 1.5 mm, gangue minerals are mainly diopside, followed by Yingshi, calcite and chlorite.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B04

Marble. The ore is grayish white, with granular crystal structure and massive structure. The mineral composition is mainly calcite, with a grayish white-white, irregular-semi-self-shaped granular structure, with a particle size of 0.5~2mm, some of which are large, with a content of more than 95%. A small amount of dolomite, timely, chlorite, etc.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B05

Siliceous rocks. The ore is grayish white-light purple, cryptocrystalline texture, massive and banded. The mineral composition is almost entirely composed of cryptocrystalline chronology, with a small amount of chlorite.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B06

Manganese oxide lead-zinc ore. The ore is characterized by structural breccia, and lead, zinc and manganese oxides mainly exist in the form of cements. The structural breccia is a variegated breccia-like structure such as black, orange and gray-black. The composition of breccia is sandstone, siltstone, siliceous rock and limestone. The diameter of breccia varies from 2 ~ 10mm, and some of them are larger, with a content of 60% ~ 75%. Cement is mainly manganese, followed by iron and clay. Lead-zinc oxides exist widely in rocks and cannot be distinguished by naked eyes.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B07

Manganese oxide lead-zinc ore. The ore is characterized by structural breccia, and lead, zinc and manganese oxides mainly exist in the form of cements. The structural breccia is variegated with orange, black, gray and gray-black, and it is a breccia structure. The composition of breccia is sandstone, siltstone, siliceous rock and limestone. The diameter of breccia varies from 2 ~ 10mm, and some of them are larger, with a content of 60% ~ 75%. Cement is mainly manganese, followed by iron, clay and so on. , and generally contains lead and zinc oxides, which cannot be distinguished by the naked eye.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B08

The monzoporphyry rocks are light purple, porphyritic and massive. Porphyry is composed of feldspar and quartz. Feldspar, with variegated colors such as grayish white, grayish green, fleshy red and dark green, short column shape, particle size of 1.5 ~ 6mm, and content of about 20%. It is colorless and transparent, with irregular granular structure, with a particle size of about 2mm and a content of about 5%. The matrix is felsic, holocrystalline or fine particles.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B09

Carbonaceous siltstone rocks are black, silty, layered and tabular. The clastic composition is silty, with a content of about 85%. Cement is carbonaceous, and its content is about 65438 05%. Fine stripes of about 2mm are developed in the rock, and plant stem and leaf fossils are distributed all over the stratum, and irregular massive pyrite is distributed sporadically.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 10

Limestone. The rock is grayish black, with microcrystalline structure and massive structure. The mineral composition is mainly calcite, with a content of about 95% and a small amount of dolomite. The rocks form reticular calcite veinlets.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 1 1

Strongly silicified granite porphyry. These rocks are light purple, mottled and huge. The phenocrysts are composed of quartz and feldspar. It is colorless, transparent, irregular and granular, with a particle size of 1 ~ 4 mm and a content of about 25%. Feldspar, light purple and grayish yellow, with a particle size of 3 ~ 7 mm and a content of about 10%, is vaguely silicified. The matrix is felsic and aphanitic.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 12

Pyrite magnetite diabase These rocks are gray-black, green and huge. Mineral composition is not easy to distinguish with the naked eye. Disseminated pyritization is developed in the rock, and it is massive locally, with a content of about 5%. Magnetite is distributed in the rock in dense disseminated form, with other shapes of granular structure, particle size 1 ~ 2.5 mm and content of about 20%. Porphyry chalcopyrite can be seen locally in the rock.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 13

Magnetite. The ore is yellowish green, iron black, brownish yellow, white and other variegated colors. Most of them are semi-authigenic granular structures, and a few of them are authigenic or heteromorphic granular structures, showing banded and variegated structures. The ore mineral is magnetite, iron black, semi-authigenic granular structure, with a particle size of 0.5 ~ 2.5 mm and a content of about 40%. Magnetite exists in dense disseminated or massive form. Magnetite is in strips and blocks. The gangue minerals are mainly diopside, with a small amount of calcite, garnet and quartz.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 14

Garnet diopside skarn Rocks are generally grayish green, with variegated colors such as iron, white and grayish brown, needle-shaped, radial or granular metamorphic structures and massive structures. The mineral composition is mainly diopside, followed by garnet, calcite and timing. Diopside, grayish green or emerald green, acicular automorphic crystal, radial aggregate, long diameter of 65438±0.5 ~ 5mm, content of about 70%. Calcite, white or colorless, semi-authigenic granular, with a particle size of 2 ~ 10 mm, up to 20mm in some cases, with a content of about 20%. Granite is grayish brown and semi-authigenic, with a grain size of 1 ~ 2.5 mm and a content of about 10%. The distribution of massive magnetite can be seen locally in the rock.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 15

Pyrite chalcopyrite ore is white, yellowish brown, yellowish green, gray and other variegated, with authigenic granular structure and variegated structure. The ore minerals are mainly chalcopyrite and a small amount of pyrrhotite. Chalcopyrite is yellowish brown, the oxide mask is ochre, semi-autotype-autotype granular, the particle size is 1 ~ 10 mm, and the content is about 50%. Pyrrhotite, yellow-green, semi-automorphic granular, with a particle size of about 1mm and a content of 5% ~ 10%. Gangue minerals are basically calcite with high crystallinity, mostly semi-autogenous crystals with a particle size of 5 ~ 20 mm

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 16

Siltstone. The rock is dark gray, with brown oxidized surface, fine-grained sandy texture and massive structure. The composition of the detritus is mainly timely, with a small amount of mica, the particle size is about 0. 1mm, and the timely content is over 90%. Cement is mainly silica, followed by iron. There are regular timely veins with a thickness of 2mm in the rock.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 17

Chalcopyrite ore. The ore presents variegated, irregular granular texture and variegated texture such as gray-gray-black, white, yellow-green, copper yellow, etc. The ore minerals are mainly chalcopyrite, with a small amount of galena, sphalerite and pyrite. Chalcopyrite, copper yellow, with ochre oxidation on the surface, irregular granules, particle size of 0.5 ~ 1 mm, mostly disseminated or irregular blocks, with a content of about 5%. Gangue minerals include calcite, diopside and quartz.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 18

Exfoliated marble. Rock is dark green, gray, white and other variegated colors, with granular crystal structure and variegated structure. The original rock is limestone, which was skarnized by thermal metamorphism and hydrothermal contact metasomatism. The mineral composition is mainly calcite and diopside, with a small amount of garnet, quartz, pyrite and marmatite. Calcite, white, semi-self-shaped granular, particle size 1 ~ 10 mm, content about 60%. Diopside, dark green or yellow-green, needle-shaped, radial aggregate, long diameter of 2 ~ 7 mm, content of about 35%.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B 19

Medium-fine grained adamellite. The rocks are light red and blue gray, with medium-fine grained granite structure and massive structure. The mineral composition consists of feldspar, quartz and mica. In time, it is colorless, transparent or smoky gray, with irregular granules, with a particle size of about 2mm and a content of about 30%. Potassium feldspar, light flesh red, short column, particle size of 65438±0 ~ 3mm, content of about 33%. Plagioclase, gray or white, short column, particle size 65438±0 ~ 3mm, content about 32%. Mica is mainly biotite, most of which has been eroded into chlorite, with a content of about 5%.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-B20

Granodiorite porphyry. The rock is grayish black, light flesh red, with spotted structure and massive structure. Rock consists of porphyritic crystals and matrix. The phenocrysts are feldspar and amphibole. Feldspar, grayish white or reddish, semi-self-shaped, short columnar, with particle size of 2 ~ 8 mm and content of about 10%. Hornblende, black or dark brown, needle-shaped, with a long diameter of 3 ~ 8 mm and a content of about 3%. Matrix aphanitic or fine-grained structure

(2) Specimen identification photos and description of their characteristics under microscope.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-b05

Siliceous rocks. Granular metamorphic texture, banded texture. The main mineral components are Yingshi (Qz, about 80%) and plagioclase (Pl, about 15%). It is irregular in shape, with a particle size of about 0. 1mm, colorless and transparent, with smooth surface, no weathering, positive and low protrusions, no cleavage and no crystallization. Plagioclase, triclinic system, colorless, negative low protuberance, developing flaky twins.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-b09

Carbonaceous siltstone silty structure, plate structure. The main mineral components are Yingshi (Qz, about 80%), plagioclase (Pl, about 15%) and a small amount of graphite (about 3%). It is irregular in shape, with a particle size of about 0.02mm, colorless and transparent, with smooth surface, no weathering, positive and low protrusions, no cleavage and no crystallization. Plagioclase, triclinic system, colorless, negative low protuberance, developing flaky twins.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-b 1 1

Strongly silicified granite porphyry. Point structure, block (strip) structure. The main mineral components are plagioclase (Pl, about 30%), calcite (Cal, about 30%), quartz (Qz, about 20%) and sericite (se, about 15%). The phenocryst is plagioclase with a plate shape and a particle size of about 2mm. Part of plagioclase is sericitized, calcite is banded, with a particle size of about 0.5mm, plagioclase, triclinic system, colorless, negative and low protruding, developing flaky twins. Calcite, rhombohedral cleavage, obvious flash, pearl halo, high-grade white interference color. Timely, colorless and transparent, smooth surface, no weathering, low protrusion on the front, no cleavage and no crystallization. Sericite is a kind of fine scaly muscovite, and its aggregate is scaly and filamentous.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-b 12

Garnet monzonite contains calcite. Granular metamorphic structure, massive structure. The main mineral components are plagioclase (Pl, about 45%), garnet (Grt, about 30%), calcite (Cal, about 10%), potash feldspar (Kfs, about 5%) and Yanshi (Q z, about 5%). The phenocryst is garnet with a particle size of about 6mm and plagioclase with a particle size of 2 ~ 3 mm It is plagioclase, triclinic, colorless, negative and low-protruding, and develops flaky twins. Garnet, equiaxed, cleavage-free, often with irregular cracks, protrudes from a suitable height and is isotropic. Calcite, rhombohedral cleavage, obvious flash, pearl halo, high-grade white interference color. Potassium feldspar, triclinic system, colorless, negative low protrusion, with inconspicuous lattice twin and oblique extinction. Timely, colorless and transparent, smooth surface, no weathering, low protrusion on the front, no cleavage and no crystallization.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-b 14

Garnet diopside skarn Granular metamorphic structure, massive structure. The main mineral components are garnet (Grt, about 65%) and calcite (Cal, about 30%). The phenocryst is garnet, which is granular, with developed cracks, with a particle size of about 6mm and calcite particle size of about 0.5 mm Garnet is equiaxed, without cleavage, and often has irregular cracks, protruding from a suitable height and showing isotropy. Calcite, rhombohedral cleavage, obvious flash, pearl halo, high-grade white interference color.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-b20

Chloritization granite porphyry. Porphyry structure, massive structure. The main mineral components are potash feldspar (Kfs, about 40%), plagioclase (Pl, about 35%), chlorite (Chl, about 15%) and a small amount of quartz (Qz, about 5%). The phenocrysts are plagioclase and potash feldspar, which are about 2mm and 1.5mm respectively, and amphibole has obvious chloritization effect. Potassium feldspar, triclinic system, negative low protrusion, inconspicuous lattice twin, oblique extinction. Plagioclase, triclinic system, colorless, negative low protuberance, developing flaky twins. Chlorite, monoclinic system, light green, weak multicolor, low interference color, grade I gray, nearly parallel extinction. In time, it is colorless and transparent, with smooth surface, low protrusion on the front, no cleavage and no crystallization.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-g0 1

The main metal minerals are magnetite, hematite, pyrite, sphalerite and beryl, with a small amount of chalcopyrite, tetrahedrite and galena. The content of magnetite (Mag) is about 65,438+05%. In the early stage (MAG 65,438+0), it was mostly a semi-automorphic-heteromorphic granular structure, which was replaced by hematite as a residual structure and was quenched by sphalerite and galena, with a particle size of 0.002 ~ 0.3mm；; Late (Mag2) metasomatic hematite. Hematite (Hem) content is about 15%, with authigenic-semi-authigenic plate-like structure, while metasomatic magnetite is residual structure, with particle size ranging from 0.001~1.0 mm. Pyrite (Py) content is about 25%, mostly with semi-authigenic-heteromorphic granular structure. Veined or marginal structure is replaced by hematite, while acute angle is replaced by sphalerite, galena and chalcopyrite. The particle size is 0.0 1 ~ 2.0 mm, and the content of andalusite (Ilv) is about 5%, showing irregular granular structure. Early magnetite, pyrite and hematite. Covered by metasomatism, replaced by sphalerite and galena. The particle size is 0.0 1 ~ 2.0 mm, the content of sphalerite (Sp) is about 1%, the particle structure is irregular, magnetite, pyrite and beryl are explained at acute angles, the particle size range is 0.0 1 ~ 1.0mm, and chalcopyrite (Ccp) is occasionally seen.

Mineralization sequence: magnetite → pyrite → hematite → beryl → sphalerite → chalcopyrite-tetrahedrite → galena.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-g02

The main metal minerals are sphalerite, chalcopyrite, galena, magnetite and hematite, and occasionally beryl, pyrite and tetrahedrite. The sphalerite (Sp) content is about 8%, with irregular granular structure. The metasomatic inclusions are magnetite and hematite, with chalcopyrite and galena in between, and the particle size is between 0.005 and 5.0 mm. The chalcopyrite (Ccp) content is about 5%, with irregular granular structure and opacified distribution in sphalerite. The sphalerite is interspersed with sharp-angled metasomatism, and covered with magnetite and hematite in the early stage. Galena presents sharp angle metasomatism, the particle size is 0.00 1 ~ 6.0mm ~ 6.0mm, and the content of Magnetite (mag) is about 2%. In the early stage, it was mostly semi-autotype-heteromorphic granular structure. Explained by hornblende hematite, it is wrapped by chalcopyrite and galena. The grain size is 0.002-0.3mm, which is later interpreted as hematite. Hematite (Hem) content is about 2%. In the early stage, it was self-shaped-semi-self-shaped plate needle-shaped, and it was an acute metasomatic magnetite with a particle size of 0.01~ 2.0 mm ~ 2.0 mm; The late aggregates are vein-like distributed in chalcopyrite and galena. Galena (Gn) content is about 65,438+0%, with irregular particle distribution, mainly chalcopyrite, sphalerite, hematite and magnetite, with a particle size range of 0.002-3.0 mm. Tetrahedrite, pyrite and beryl are occasionally found.

Mineralization sequence: magnetite → pyrite → hematite → beryl → sphalerite → chalcopyrite-tetrahedrite → galena.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-g03

The main metal minerals are pyrite, sphalerite, chalcopyrite, galena and a small amount of beryl, magnetite and hematite. The content of sphalerite (Sp) is about 25%, showing irregular granular structure. Substitutes include magnetite, hematite, etc. , interspersed with chalcoPyrite and galena in sharp corners or veinlets, with a particle size of 0.005 ~ 3.0mm and a pyrite (py) content of about 5%, showing an automorphic-semi-automorphic granular structure. It is marginal structure, replaced by chalcopyrite, sphalerite and galena, and partially dissolved by beryl, with a grain size range of 0.01~1.5 mm. The chalcopyrite (Ccp) content is about 65,438 0%, with irregular granular structure, and sphalerite, pyrite and beryl are intercalated between veinlets. In the early metasomatic inclusions, magnetite, hematite and pyrite show inclusion structure, and the grain size range is 0.001~ 0.5 mm. Galena (Gn) content is about 1%, with irregular granular structure, sharp corners or veinlets, with chalcopyrite, sphalerite and beryl in between, and the particle size range is 0.002 ~1.2mm. Hematite (Hem) content is about 2%. In the early stage, it was self-shaped-semi-self-shaped plate-like and needle-like, and then it was replaced by sharp-angled magnetite. It is strongly replaced by galena locally, showing residual structure, and the particle size range is 0.01~ 0.2 mm; The late aggregates are veined and scattered in sphalerite. A small amount of andalusite (Ilv) and magnetite (mag)

Mineralization sequence: magnetite → pyrite → hematite → beryl → sphalerite-chalcopyrite → galena.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-g07

The main metal minerals are pyrolusite, galena, limonite and a small amount of pyrite. The content of pyrolusite (Ps) is about 2%, which is distributed in transparent minerals in the form of microcrystal aggregates with turtle cracks in some areas. The internal structure is a radial aggregate with a particle size of 0.001~ 0.02 mm. The content of galena (Css) is about 8%, and the aggregate is fibrous and bell-shaped with a particle size of less than 0.02 mm. Limonite (Lm) content is about 2%, mainly early pyrite. Automorphic particles completely retain their crystal morphology, showing the characteristics of pseudo-structure, and the particle size is between 0.01~ 0.2 mm. A small amount of pyrite (py) is distributed in transparent minerals in the form of semi-autotype-allotropic particle structure, most of which are completely pseudo-structure, and the particle size is 0.01~ 0.05 mm.

Mineralization sequence: pyrite → pyrolusite → galena-limonite.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-g 12

The main metal minerals are molybdenite, chalcopyrite and galena, with a small amount of pyrite, sphalerite, hematite and tetrahedrite. The content of chalcopyrite (Ccp) is about 65,438+0%, and it has an irregular granular structure, and locally it has a * * knot structure with tetrahedrite and galena, with a particle size of 0.002-0.65,438+0 mm, and a small amount of molybdenite (Mot) has an authigenic-semi-authigenic tabular crystal structure. It can be seen that galena has a sharp-angled structure along its grain edge, and its particle size is between 0.001~ 0.02 mm. A small amount of galena (Gn) has an irregular granular structure, and it is metasomatic along the gap between molybdenite particles, and locally contacts with chalcopyrite, with a particle size of 0.01~ 0.05 mm. Tetrahedrite (Td) is rare, with irregular granular structure and * * junction structure with chalcopyrite, and its particle size is about 0.01mm. Occasionally sphalerite

Mineralization sequence: pyrite → molybdenite → sphalerite-chalcopyrite-tetrahedrite-galena → hematite.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-g 13

The main metal minerals are magnetite, a small amount of hematite, spinel and siderite. Magnetite (Mag) content is about 60%, mostly in semi-autotype-heteromorphic granular structure, and the particles are relatively broken, characterized by fragmentation structure. The locally wrapped spinel fine particles are in inclusion structure or solid solution separation structure, the later hematite metasomatism is in veinlets or sharp-angled structure, and the later siderite metasomatism is in strong residual structure, and the particle size is between 0.0 1 ~ 2.0 mm along the edge of magnetite particles, with a small amount of hematite (Hem) and sharp-angled or veinlets along the cracks and edges of magnetite particles. The particle size is between 0.00 1 ~ 0. A small amount of spinel (Sn) is distributed in magnetite particles in authigenic granular structure, and its triangular and quadrilateral crystal sections can be seen, with the particle size range of 0.001~ 0.0/mm. A small amount of siderite (Sd) with irregular granular structure is distributed along the edge of magnetite particles, with the particle size.

Mineralization sequence: magnetite-spinel → hematite → siderite.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-g 15

The main metal minerals are pyrite, magnetite, hematite and limonite, with a small amount of chalcopyrite, sphalerite, galena and celestite. Pyrite (Py) content is about 35%, and it has an authigenic-semi-authigenic granular structure, and the broken particles have a fragmented structure. The wrapped magnetite particles are in inclusion structure, and magnetite is replaced by chalcopyrite, sphalerite and hematite with sharp-angled structure. The residual structure has strong local metasomatism, and the particle size is between 0.01~ 5.0 mm. Magnetite (Mag) content is about 65,438+0%, mostly in semi-automorphic-heteromorphic granular structure, pyrite in veinlets or inclusions, and chalcopyrite and hematite in the later stage in sharp corners ... Hematite (Hem) content is about 65,438 0%, with autogenous plate-like or needle-like autogenous granular structure and radial aggregate, and magnetite and pyrite in sharp corners. Some chalcopyrite (Ccp) has an irregular granular structure, and is in slow contact with sphalerite in a * * * knot shape, and some chalcopyrite and magnetite particles are in sharp corners, which is a ring-edge structure with sky blue metasomatism. The particle size is 0.00 1 ~ 0.4 mm ... A small amount of sphalerite (Sp) is irregularly distributed in particles, and it is * * * with chalcopyrite, with some sharp-angled pyrite particles, which are replaced by sharp-angled galena with a particle size of 0.002 ~ 0.2 mm. A small amount of sky blue (Cv) and limonite (Lm). Occasional galena

The sequence of mineral formation is magnetite → pyrite → hematite → chalcopyrite-sphalerite → galena → sky blue → limonite.

Series of specimens and optical slices of typical deposits in China. Lead-zinc-antimony-silver-gold deposit

PbZn3-g 17

The main metal minerals are sphalerite, galena and chalcopyrite, with a small amount of pyrite, tetrahedrite, magnetite, hematite, celestite and limonite. The content of sphalerite (Sp) is about 20%, and it has irregular granular structure. Early magnetite is explained by sharp corners, and chalcopyrite and galena in sharp corners or veinlets. The local explanation is a strong Hong Kong Island structure, with a grain size of 0.005-2.5mm and chalcopyrite (Ccp) content of about 10%. It is an irregular granular structure, distributed in sphalerite in the form of solid solution separated droplets, and the contact edge with sphalerite and tetrahedrite is flat, showing a * * * edge structure, and some parts are sharp-angled or veinlets, accounting for sphalerite and pyrite. The particle size is between 0.0065438 ... The galena (Gn) content is about 65438 00%, showing irregular granular structure, sharp-angled structure or veinlet structure, which accounts for magnetite, pyrite, sphalerite, chalcopyrite, etc. Pyrite (Py) content is low, with a semi-autotype-heteromorphic granular structure, with sharp-angled metasomatic magnetite or hematitization pseudomagnetite particles, which are wrapped by late sphalerite, chalcopyrite, tetrahedrite and galena, and the particle size is 0.01~ 0.6 mm. A small amount of magnetite is in a semi-autotype-heteromorphic granular structure, which is covered by late pyrite, hematite, sphalerite, galena and galena. The hematite (Hem) is in the form of residual skeleton crystal structure or inclusion structure, with a particle size of 0.065438 0 ~ 0.3 mm. Most of the hematite (HEM) is in the form of irregular granular structure, and some of it is in the form of plate and needle-like semi-autogenous crystal structure, mainly with sharp-angled metasomatic magnetite, with a particle size range of 0.001~ 0.2 mm. A small amount of tetrahedrite (Td), sky blue and ..

Mineralization sequence: magnetite → hematite → pyrite → sphalerite → chalcopyrite → tetrahedrite → galena → azure → limonite.