Deposits formed by exogenic mineralization on the surface of the earth
Exogenic mineral deposit refers to the deposit formed by exogenic mineralization on the surface of the earth.It is formed by the migration and enrichment of ore-forming materials under the interaction between the lithospheric surface and the hydrosphere, atmosphere and biosphere.The ore-forming materials of exogenic deposits mainly come from the surface layer of the crust, and some of them are brought to the surface by the materials inside the earth through volcanoes, air jets or hot springs.
Chinese name
Exogenetic deposit
Foreign name
exogenic mineral deposit
Nature
deposit
Source
Crust surface
economic value
All coal, oil and natural gas;Exogenous deposits include all coal, oil and natural gas, most aluminum and manganese ores, most cobalt ores and iron ores, some nonferrous and rare metal minerals, as well as important agricultural fertilizers and chemical raw materialsOther non-metallic minerals
Energy source
Solar energy, ground energy, biological energy, chemical energy
Geography (topography and climate) not only determines the weathering, denudation, sedimentary characteristics, types, speed and development degree of rocks or deposits, but also determines the sedimentary facies, sedimentary formation and formation of various exogenous deposits.
The ocean is of great significance to sedimentary deposits: useful elements (salts) in seawater;Seafloor ferromanganese nodules;Fossil energyEtc.
Fluvial processes are also important: deposits related to delta, littoral and shallow sea deposits (placers, carbonates, fossil energy)
type
Announce
edit
Weathered deposit
The deposit formed by the enrichment of some stable and useful components in or near the original place in the weathering process of the surface rocks of the crust (including ore bearing parent rocks and primary deposits) is called weathered deposit.According to the weathering type, weathering material, accumulation location and modeEluvial placer deposit, slope deposit, residual deposit and eluviation deposit.
Sedimentary deposit
Under the action of surface external forceSedimentary differentiationDeposits formed by enriching useful components are called sedimentary deposits.This type of deposit is consistent with the formation conditions and process of sedimentary rocks, so it has the same general characteristics as sedimentary rocks, such as bedding, some containing fossils, the horizon is relatively stable, sometimes large, and ore prospecting and exploration are relatively easy.According to its formation mode, it can be divided intoMechanical deposit, chemical and biochemical sedimentary depositsCombustible organic rockDeposit.The most information - help growth - emotional affinity
Combustible organic rock deposit
This is a kind of organic deposit that can be used as fuel energy, including coal, oil, natural gas, oil shale, etc.The so-called energy refers to the material that can produce energy, or refers to the resources that can be converted into various energies such as mechanical energy, thermal energy, electromagnetic energy and chemical energy.Therefore, this type of deposit occupies an extremely important position in the national economy and people's livelihood as well as in the international strategic resources.Of course, the use of coal and oil is not limited to energy, especially oil, which is related to almost all industries.Combustible organic rock minerals account for more than 3/4 of the world's total output of mineral raw materials or total output value, which shows that this type of deposit is of special significance.[1]
characteristic
Announce
edit
The exogenetic deposit is characterized by its formation in the surface environment, and its mineralization temperature and pressure are low, generally not more than 100 ℃ and 20 atmospheres.The transport medium of ore-forming materials is mainly water, and the pH value andRedox potential(Eh) is easily affected by the environment and changes, which is an important factor to promote the differentiation and enrichment of substances.Colloids are widely distributed under surface conditions. Their strong adsorption and ion exchange capabilities are another important way to enrich some elements.In addition, biological activities can directly aggregate some useful substances, or change the physical and chemical conditions of the aqueous solution to facilitate the precipitation of minerals.
