(XVII) Detailed investigation of physical and geological data of Jiaojiao Goldstone Mine in xinyi city, Jiangsu Province.

The detailed investigation project of Jiaojiao Jinhongshi Mine in xinyi city, Jiangsu Province is one of the geological exploration projects subsidized by the central government in 2005 (Su Cai Jian Zi No.00373). The main task of this project is: on the basis of predecessors' work, through systematic sampling engineering. Further control the overall distribution range of ore bodies, and basically find out the characteristics and spatial distribution of ore bodies in mining areas; Basically find out the material composition and ore quality of the ore; Comprehensive evaluation of associated minerals such as garnet and omphacite: The technical conditions of deposit development have been basically found out.

The field work of this project mainly adopts the combination of high-precision magnetic survey, hand twist drill and mechanical core drill. The accumulated main physical workload is 1∶2000 topographic survey 1.7 1km2, high-precision magnetic profile 10.40km, hand twist drill 18 1.03m, and mechanical coring drill/kloc. In the field work, the hidden ore-bearing eclogite is discovered and tracked in advance by using high-precision magnetic survey technology, and the solid minerals are innovatively exposed in the shallow covering areas which are difficult to construct, such as surface control troughs and shallow wells, which provides a scientific and effective technical method for finding and delineating ore-bearing eclogite in the shallow covering areas.

Through investigation, the characteristics of strata, structure and Mesozoic dikes in the mining area, as well as the rock types and lithologic characteristics of metamorphic rocks in the mining area, have been found out, and the shape, scale, occurrence and petrological characteristics of rutile ore-forming mother rock eclogite have been mastered. Through the systematic analysis of the samples, 8 rutile ore bodies are circled.

1. Regional geological background

The mining area is located in the east extension of Qinling-Dabie orogenic belt-the southwest edge of Sulu orogenic belt. The Sulu orogenic belt is sandwiched between two plates, the North China plate in the north and the Yangtze plate in the south. Located in Jiangsu Province, this belt is about 140km long and 90km wide. It is mainly composed of NeoArchean-Proterozoic Yudonghai Group, Jinping Group, Yuntaishan Group and intermediate-acid metamorphic plutonic intrusive rocks, in which a large number of ultrahigh-pressure eclogites are distributed, and primary rutile minerals are produced in eclogites.

(1) regional layer

The strata developed in the northern Jiangsu orogenic belt mainly include the Neoarchean-Proterozoic Donghai Group, the Mesoproterozoic Jinping Group, the Neoproterozoic Yuntaishan Group and the Sinian Shiqiao Group. Due to strong metamorphism and deformation, most of the original rocks have been transformed and are difficult to identify.

East China Sea Rock Group: distributed in Xinpu, Haizhou and Luanhong. Xiaxishan Formation consists of dark green mudstone with marble, phospholimestone, quartzite, graphite schist and manganese phosphate rock. The upper part of Dongshan Formation consists of dolomite albite granulite, phosphorus-containing marble, phosphorus limestone and green-green argillaceous calcareous mica schist.

Yuntai Rock Group: distributed in Yuntai Mountain area and the residual hills from Shuyang to Guanyun in the south. The lithology is mainly granulite and granulite, with dolomite schist, kyanite quartz schist and quartzite. The protolith is a set of intermediate-acid volcanic-clastic sedimentary rocks, siliceous rocks and spilite, which were formed on the active continental margin and transformed by low greenschist facies metamorphism and late ductile deformation.

Shiqiaoyan Formation: a set of shallow metamorphic rocks, only found in Shiqiao, Ganyu. The main lithology is metamorphic dolomite sandstone, metamorphic quartz sandstone containing dolomite, metamorphic gravelly feldspathic sandstone, dolomite schist and dolomite phyllite.

Cretaceous: It is mainly distributed in NNE, NE and NW fault basins, and the lithologic combination is tuff, andesite tuff, sandstone, shale and gravel sandstone.

Paleogene: mainly distributed in Anfengshan and southern Shuyang Basin, with a set of continental red clastic rocks, including gravelly sandstone, coarse sandstone, silty sandstone and silty mudstone.

Quaternary: widely distributed, mainly clay sand, sandy clay, gravel and coarse sand in mountainous areas, hills and their vicinity; The plain area is dominated by sandy clay and clay.

(2) Regional structure

The main structural types of Subei orogenic belt are ductile rheological structure and brittle fracture structure.

Ductile rheological structure is the main structural form in metamorphic rock area, which is embodied in surface line structure, fold structure and ductile shear zone.

Brittle fault structure changed the structural pattern of metamorphic rocks and controlled the distribution of Mesozoic magmatic rocks and the formation of tectonic basins. Fault structures are dominated by NE and NE, followed by NW, nearly North-South and nearly East-West.

(3) Regional magmatic activity

Magmatic activity is strong and magma is widely distributed in the orogenic metamorphic belt in northern Jiangsu. Neoarchean-Proterozoic basic-ultrabasic rocks and granitic metamorphic plutonic intrusive rocks are the main rocks. Followed by Mesozoic intermediate-acid intrusive rocks and a small amount of Cenozoic volcanic rocks.

1) Neoarchean-Proterozoic intrusive rocks. Metamorphic plutonic intrusive rocks are all kinds of gneiss formed by regional metamorphism of meso-Neoproterozoic granitic intrusive rocks, which are the main body of metamorphic rocks in this area and the main surrounding rock of ore-bearing eclogite bodies.

2) Mesozoic intrusive rocks. According to the emplacement age, the Mesozoic intrusive rocks in this area can be divided into Taolinchao unit and Zhucangchao unit, and the main lithology is adamellite, granodiorite and lamprophyre. Rock masses and dikes are generally distributed in the northeast-southwest direction.

3) Cenozoic volcanic rocks. The main lithology is basalt and volcanic breccia, which are distributed in Anfengshan, Pingmingshan and other places and are oval in north-south direction and northeast direction.

(4) regional metamorphism

Metamorphic rocks in Subei orogenic belt are widely distributed, and the lithology is mainly gneiss, granulite, amphibole, marble, schist, serpentine and eclogite.

Metamorphic rocks in this area have undergone multi-stage metamorphism. greenschist facies, amphibolite facies and eclogite facies are well preserved, but traces of granulite facies remain in some areas, basically preserving the metamorphic process of eclogite facies-amphibolite facies-greenschist facies.

Metamorphic rocks in Subei orogenic belt not only suffered from regional metamorphism of multiple stages, but also suffered from high-pressure and ultrahigh-pressure metamorphism during the collision, subduction and exhumation of North China plate and Yangtze plate.

(5) Regional minerals

The known types of mineral resources in this area are metal, nonmetal and geothermal. Metal minerals are relatively scarce. Non-metallic minerals are abundant, mainly including phosphorus, crystal, rutile, kyanite, diamond, serpentine, marble, porcelain stone, fluorite, mica, graphite, quartzite, granite, basalt, yellow sand, brick clay and so on. Among them, phosphorus, crystal, rutile, kyanite and serpentine are the dominant minerals in this area.

(6) Characteristics and ore-bearing property of regional eclogite.

There are more than 2000 kinds of eclogites formed by ultra-high pressure metamorphism in the northern Jiangsu orogenic metamorphic belt, and eclogites generally contain a certain amount of rutile. Rutile content varies with rock mass, lithofacies and lithology, and it is estimated that it can be enriched by about 50% to become a complete ore body. At present, many primary eclogite rutile deposits (spots) have been found in this area, and only three large-super large deposits have broad prospecting prospects.

Eclogites are distributed in groups and zones, and large rocks are thousands of meters long and hundreds of meters wide. The smallest is only a few meters to dozens of centimeters. The shape of rock mass is complex and diverse, mostly lenticular, layered, elongated and lentil, which reflects the transformation of ductile metamorphism in the later stage. A few people with strong deformation distort and even form folds or structural hooks, which are moon-shaped and horseshoe-shaped on the plane.

Eclogite mainly occurs in Proterozoic metamorphic plutonic intrusive rocks, and its surrounding rocks are mostly amphibole, biotite granulite, biotite plagioclase gneiss and other metamorphic rocks. The general trend of eclogite belt is consistent with the steering wheel of the main tectonic line in the northeast of this area; There are often ductile shear zones in eclogite distribution areas.

Eclogite can be divided into massive eclogite, gneiss eclogite and banded eclogite according to its structure, with massive eclogite as the main one. The mineral composition can be divided into (including) rutile eclogite, muscovite eclogite, timely eclogite, kyanite-bearing mica eclogite, zoisite eclogite, biotite eclogite, secondary eclogite, garnet eclogite and greenstone. , mainly (including) rutile eclogite, a small amount of other eclogites.

The metamorphism of eclogite has gone through pre-eclogite stage, eclogite intensive stage, post-eclogite stage, early metamorphic stage and late metamorphic stage.

The ductile deformation of eclogite often changes the shape of rock mass, leading to the directional arrangement and structural changes of minerals in rock. With the increase of deformation intensity, massive eclogite is transformed into gneiss or even banded eclogite.

2. Geology of mining area

The mining area is located on the east side of the Tan-Lu fault zone and at the southwest end of the ultrahigh pressure metamorphic belt in the northern Jiangsu orogenic metamorphic belt. In the structural slice division of ultra-high pressure metamorphic belt in northern Jiangsu, the mining area is located at the southwest end of Qiqiushan-Baitabu-Ganyu structural slice.

(1) mining stratum

Quaternary covered the whole area. The other layers belong to the late Pleistocene Qizui Formation, and the genetic type is residual slope accumulation. The lithology is divided into five layers from top to bottom: cultivated soil, brown clay silt, brown-taupe iron nodule clay layer, brown-taupe calcareous nodule clay layer and gravel layer.

(2) Mining area structure

The structure of the mining area is relatively simple, generally single italic. Tectonic systems can generally be divided into plastic rheological structures and brittle fracture structures. The two types of structures have different functions in the process of regional geological development, and the transformation of eclogite rutile deposits is also different.

(3) Magmatic activities in the mining area

The mining area is located in the south of Xinyi-Rizhao-Qingdao magmatic activity belt, with strong magmatic activity and multi-cycle characteristics. In the late or late Lvliang movement, due to the mantle interaction, the crust partially melted, forming adamellite magma, which invaded in situ or along the early structural weak zone, leading to the deep emplacement of large-scale intermediate-acid magmatic rocks in the area. After complex geological transformation, the main rock of the mining area-Precambrian granitic metamorphic intrusive rock was formed. In addition, there are scattered Mesozoic dikes in this area.

(4) Metamorphic rocks and metamorphism in the mining area

The metamorphism in the mining area has experienced multi-stage metamorphism. According to the characteristics of mineral assemblages and related data, metamorphism in the area can be divided into three stages: eclogite facies metamorphism, low amphibolite facies metamorphism and greenschist facies metamorphism.

(5) The characteristics of eclogite in the mining area and its ore-bearing property.

Eclogite is the parent rock of primary rutile in this area. The rock mass is strip-shaped, layered and lenticular, generally trending northwest, partially distorted and generally trending northeast. The surrounding rocks of rock mass are mainly gneiss, and thin amphibolite is often produced at the edge. There are three types of rocks in the mining area:

1) massive eclogite: it is the main eclogite type in the mining area. Light green-dark green, with dark red spots or stripes, granular columnar crystal structure, mainly block structure, a small amount of strip structure.

2) gneissic eclogite: it belongs to the type of secondary eclogite in mining area. Gray-green-green with red stripes or spots, (scaly) columnar granular crystal structure, flaky or striped structure.

3) banded eclogite: it is rare in mining area, mainly because garnet and greenstone are relatively concentrated in banded and massive distribution after deformation-retrogression of eclogite.

3. Bored core collection

Small-coke rutile is a rare rutile-rich titanium ore with the highest content and the largest thickness in China, and it is also the first time that a large metamorphic rutile deposit with titanium dioxide content greater than 3% has been discovered in China. Collect and keep 3 boreholes in the mine.

ZK 1 10 1 drilling, the hole depth146.07m ... passes through multi-layer ore bodies, and there are biotite plagioclase gneiss, hypoamphibolite gneiss eclogite, plagioclase amphibolite, gneiss eclogite, gneiss rutile and massive rutile in the hole. The ore minerals are rutile, grayish green, crimson or purplish red, granular columnar crystal structure, massive and gneiss structure.

ZK 1702 drilling hole, with a hole depth of 109.24 m, passes through multi-layer ore bodies, and gneiss, ore-bearing gneiss, massive rutile, gneiss, biotite plagioclase gneiss, ore-bearing massive eclogite, dolomite plagioclase gneiss, biotite plagioclase gneiss and so on can be seen in the hole. The ore minerals are rutile, gray-gray-green, gray-green with dark red, granular columnar crystal structure, massive and flaky structure.

ZK2 102 drilling hole, with a hole depth of 186.26 m, passes through multi-layer ore bodies, and there are monzonitic gneiss, biotite amphibole gneiss, biotite amphibole gneiss, green curtain biotite monzonitic gneiss, massive rutile, ore-bearing massive eclogite, massive eclogite, etc. The ore mineral is rutile, gray-green, with dark red spots, medium and fine particles, columnar crystal structure and massive structure.

4. Relevant information

1) xinyi city 1 1 line resource estimation profile of Jiaojiao Jinhongshi mining area;

2) General situation of resource estimation of xinyi city Jiaojiao Jinhongshi mining area 17 line;

3) Geological map of bedrock in xinyi city Jiaojiao Jinhongshi mining area;

4) Profile of 2 1 line resource estimation in Jiaojiao Jinhongshi mining area, xinyi city;

5) ZK 1 10 1 borehole histogram of small coke rutile mining area;

6) ZK 1702 borehole histogram of small coke rutile mining area;

7) Borehole histogram of ZK2 102 in small coke rutile mining area;

8)ZK2 102 borehole geological record book;

9)ZK 1702 borehole geological record book;

10)ZK 1 102 borehole geological record;

1 1) Detailed geological report of small pyrite rutile mine in xinyi city, Jiangsu Province (geological part).