Breccia

Classification：Sedimentary Rock

Coarse grained rock formed by a high angle fragment cemented. Breccia is coarse, and visible gravels can be seen. There are many reasons for it, such as slump accumulation, volcanic eruption, rock collapse and so on.

Breccia, like conglomerate, is also a clastic rock, which is broken down from the parent rock and has a diameter of more than 2 millimeters in diameter. The rock is formed by transporting, depositing, compacting, and cementing. The average diameter of the gravel is 1-10 millimetres, 10-100 millimeters of gravel, and more than 100 millimeters of boulder. Its cements often contain minerals, and Breccia can also be used as building materials. Breccia is relatively rough, and obvious gravel can be seen. If more than 50% of the rubble of the cemented rock is rounded to conglomerate and more than 50% with angled angle, it is called Breccia.

Brecciabreccia deposited a kind of clastic rock. It is cemented by angular gravels larger than 2 millimeters. The detritus substance that forms Breccia is usually very short because of its accumulation or transportation distance in situ, so the grinding degree is very low, the sorting is very poor, the shape is different, the edges and corners are distinct.
According to the cause of formation, it can be divided into karst Breccia, volcano Breccia, piedmont accumulation Breccia, glacier Breccia, fault Breccia (also known as tectonic Breccia), diagenetic Breccia, and meteorite impact Breccia, etc. Studying Breccia can help restore paleogeographic environment, deduce tectonic alteration, and some minerals are related to Breccia.
Breccia can well reflect the composition and properties of the parent rock, and it is more closely related to the parent rock than the conglomerate. According to origin, Breccia can be divided into residual, interlayer, debris flow, collapse, diagenesis, tectonics and volcanoes.
Such as limestone cave top, collapse due to dissolution, calcareous breccia is cemented by calcareous or red soil, and can form collapse Breccia (cave Breccia). During diagenetic stage, due to colloid dehydration, volume contraction, rock fragmentation and breccia, cementation, it can generate diagenetic Breccia (conglomerate).

Genetic classification:
The shoreline conglomerate: mainly formed in the coastal area and the Binhu area, it is reformed by the waves and rivers of the gravel or the collapse of the coastal rocks.
River conglomerate: the conglomerate formed by mountain river and plain river is called River conglomerate, mostly composed of lithic conglomerate. The average diameter of gravel is larger than that of marine gravel, but gravel sorting is poor.
Moraine conglomerate: the gravel is mainly composed of silt and muddy clastic. The gravel grade is 5-30%, with poor particle size and poor sorting. The identification characteristics of the moraine rocks are: the shape of the gravel is peculiar, forming the so-called five boulders or ironing gravel, and the surface has a T-shaped scratch.
Karst Breccia (collapse Breccia, cave Breccia): carbonate rock formed karst cave because of dissolution, caves caving and caving and forming limestone, dolomitic breccia accumulation, and then caused by calcareous or laterite cementation.
Volcano Breccia: a rock formed by cementation of fine debris (volcanic ash and glassy) between 2 - 64mm of volcanic debris (debris, slurry, more than 30% of the volume of the whole rock). With the lava than for Clastic tuff, but the glass flakes and less crystal chips.

Some volcanic Breccia has a large amount of volcanic rock slag, the gravel block has many prism, the diameter is about ten to thirty common separation, the accumulation is not obvious stratification, the separation is poor, all by the volcanic material cementation, a part of the block rock cemented tightly, there is no obvious boundary between the gravel and the cementation. Volcanic Breccia can be distributed on volcanic slopes not far from the crater, but often occurs at the beginning stage of eruption cycle and after accumulation of lump rock. Volcanic Breccia is a prospecting indicator for finding volcanic deposits and volcanic structures controlled by volcanic structures. Because of its good permeability, it is usually a host rock.
Fault Breccia or structure Breccia: in stress action (fault action), the original rock is broken into breccia, the rock is cemented by broken fine chips or with some foreign material cemented. It is generally believed that the content of breccia debris is more than 30%, which is called fault Breccia, while the content of debris is less than 30%, which is called fault gouge. It is a medium rock with a moderate degree of fragmentation in dynamo metamorphic rocks. The tectonic Breccia is widely distributed in the fault zone. The thickness depends on the strength of the crushing. Sometimes it can be as thick as hundreds of meters, extending from dozens to hundreds of kilometers.

If the hydrothermal pressure is greater than the static pressure of the overlying rock, the volatilization of the volatiles escapes and the volume expands rapidly, the Breccia formed by the hydrothermal blasting of the surrounding rock is called as a result.
Magmatic explosion Breccia (magmatic explosion Breccia): in the shallow or ultra shallow environment, the blasting or volcanic activity, or latent volcanism (hidden explosion), occurred at the top of the magma under the pressure of the magma blasting stress. The most direct factor of the explosion of magma is the multi source fluid or gas which is heated. The main way of the magmatic concealment blasting is gas explosion and slurry explosion, followed by the injection of hydrothermal solution. Usually, gas explosion occurs early, and pulp burst is later. Hydrothermal injection is the latest. The shallow to ultra shallow intermediate acid porphyry is the decisive factor for the formation of Breccia. Its genesis is similar to that of Breccia in hydrothermal blasting.
Metallogenic mechanism:

Breccia metallogenic mechanism
The contact boundary between rock and surrounding rock is clear, and the contact boundary between rock and surrounding rock is clear. Most of them are fault contact. It is not clear that the boundary line is not clear when the local edge of the rock tube is relatively developed at the local edge of the rock. But the boundary line is not clear when the alteration mineralization is gradually changed, but the boundary line is still found. The only sign of the identification is Breccia into the tube, but it is difficult to distinguish only from alteration and mineralization, because the alteration mineralization is often very strong at the part of the wall crack development.
For example, the development of the wall cracks in the newly developed ore bearing rock tube can form the ore body with high-grade grade. First, after the formation of the cross section of the fracture structure of the rock tube controlled by a new ore bearing rock cylinder, the rotation of the whole rock barrel was involved because of the reactivity of the north west direction and the reverse fault, causing the contact edge fracture to be distributed in a left-hand way. At the same time, Breccia bodies were also broken to different degrees, which provided a good space for later hydrothermal filling mineralization.

The components of the 1Breccia stone are basically the same as the Breccia components in the ore - free and ore - free Breccia tubes, including granite diorite, corner rock, fine rock and rhyolite porphyry, British safety porphyry, granite porphyry, etc. The statistics show that the breccia is mainly composed of granodiorite, the percentage of its area is 8090, and the other lithologic breccia is only a small part, and it can be seen that the granite diorite and breccia are gradually decreasing from upper to lower, while the breccia and the breccia of the British safety porphyry are gradually increased by the fine rock.
The size and morphological characteristics of breccia are different, from a few meters (3~4) to fine particles, and the size of the 78 mine is 03 to 5 meters in 1995, and the change rule is in the range of 10 meters. The grain size of the breccia is smaller than the middle part, and the particle size decreases gradually from the upper to the lower. For angular subangular, small round and round in half. There is no obvious sorting, generally non directional arrangement. Only a small amount of breccia long axis near the local edge of rock tube is arranged near parallel veins.

Breccia tube structure
However, there are no traces of tectonic activity in these locations, indicating that the breccia arrangement is not structural origin but gas liquid migration. Figure 3 the orientation of the directional flow structure of the edge of the new rock tug Xinxing pit 0 rock tug 1 is 1 a Kerr 2 kerbrock, and the 3 one has conglomerate. The cemented objects are mainly smaller than 2 gray to white or pink siliceous debris or rock powder, and the debris or rock powder has been strongly eroded into dolomite to illite. The breccia is broken into breccia and cemented by quartz to sulphide (mainly sphalerite and galena) in the Breccia of ore bearing quartzite, obliquely epidote or epidote secondary quartzite.
It is indicated that lead-zinc mineralization in ore bearing rock tube is a Breccia tube lead-zinc deposit which is rich in lead and zinc ore-forming hydrothermal fluid after the formation of the rock barrel. The chemical composition of Breccia is characterized by the chemical comparison of ore bearing and ore free Breccia and granodiorite.
It can be seen that there is no significant difference in chemical composition between Breccia and granodiorite. In the ore bearing Breccia, a large number of components are brought into the group, and the second is that a large number of them are taken out, the general ore bearing Breccia0/0, the +/0+0 ratio are more than 2, while the ore free Breccia and the granodiorite 0/: 0, + /. + ratio is 1. It shows that after the formation of the rock barrel, the ore bearing rock tube is still rich in the late stage, and the ore bearing hydrothermal fluid is brought into a large amount, which is one of the major differences between ore bearing and ore free Breccia, and it is of great significance to correctly understand the genesis of the ore bearing Breccia.