| dbo:abstract
|
- Hydrothermal mineral deposits are accumulations of valuable minerals which formed from hot waters circulating in Earth's crust through fractures. They eventually create metallic-rich fluids concentrated in a selected volume of rock, which become supersaturated and then precipitate ore minerals. In some occurrences, minerals can be extracted for a profit by mining. Discovery of mineral deposits consumes considerable time and resources and only about one in every one thousand prospects explored by companies are eventually developed into a mine. A mineral deposit is any geologically significant concentration of an economically useful rock or mineral present in a specified area. The presence of a known but unexploited mineral deposit implies a lack of evidence for profitable extraction. Hydrothermal mineral deposits are divided into six main subcategories: porphyry, skarn, volcanogenic massive sulfide (VMS), sedimentary exhalative (SEDEX), and epithermal and Mississippi Valley-type (MVT) deposits. Each hydrothermal mineral deposit has different distinct structures, ages, sizes, grades, geological formation, characteristics and, most importantly, value. Their names derive from their formation, geographical location or distinctive features. Generally, porphyry-type mineral deposits form in hydrothermal fluid circulation systems developed around felsic to intermediate magma chambers and/or cooling plutons. However, they did not precipitate directly from the magma. While, a skarn deposit is an assemblage of ore and , formed by metasomatic replacement of carbonate rocks in the contact aureole of a pluton. Volcanogenic massive sulfide deposits form when mafic magma at depth, (perhaps a few kilometers beneath the surface), acts as a heat source, causing convective circulation of seawater through the oceanic crust. The hydrothermal fluid leaches metals as it descends and precipitates minerals as it rises. Sedimentary exhalative deposits, also called sedex deposits, are lead-zinc sulfide deposits formed in intracratonic sedimentary basins by the submarine venting of hydrothermal fluids. These deposits are typically hosted in shale. Hydrothermal epithermal deposits consist of geological veins or groups of closely spaced geological veins. Finally, Mississippi Valley-type (MVT) are hosted in limestone or dolomite that was deposited in a shallow marine environment in a tectonically stable intraplate environment. As expected in such an environment, volcanic rocks, folding and regional metamorphism are absent as a general rule. MVT deposits commonly lie in close proximity to evaporites. (en)
- Deascadh mianraí ó shreabháin uisciúla theo taobh istigh de screamh an Domhain, atá bainteach le gníomhaíocht dhoigheartha. Cruthaíodh cuid mhaith de na mianaigh thábhachtacha mianraí i ndeascáin fhéitheacha hidriteirmeacha. (ga)
- 열수 광상은 열수의 작용으로 이뤄진 광상이다. 수증기와 휘발성 성분이 암석중의 틈을 따라 이동하는 동안 온도가 374°C이하로 떨어지면, 수증기는 여러 가지 성분을 포함한 열수로 변한다. 이 열수용액이 틈속을 지나가며 틈을 넣거나, 온도가 더 낮아지면 그 틈 속에 여러 가지 광물을 침전시킨다. 광상의 생성 온도에 따라, 심열수, 중열수, 천열수, 최천열수, 제노서멀 로 구분하며, 주로 금, 은, 납, 아연, 구리, 안티모니등 이 산출된다. (ko)
|
| rdfs:comment
|
- Deascadh mianraí ó shreabháin uisciúla theo taobh istigh de screamh an Domhain, atá bainteach le gníomhaíocht dhoigheartha. Cruthaíodh cuid mhaith de na mianaigh thábhachtacha mianraí i ndeascáin fhéitheacha hidriteirmeacha. (ga)
- 열수 광상은 열수의 작용으로 이뤄진 광상이다. 수증기와 휘발성 성분이 암석중의 틈을 따라 이동하는 동안 온도가 374°C이하로 떨어지면, 수증기는 여러 가지 성분을 포함한 열수로 변한다. 이 열수용액이 틈속을 지나가며 틈을 넣거나, 온도가 더 낮아지면 그 틈 속에 여러 가지 광물을 침전시킨다. 광상의 생성 온도에 따라, 심열수, 중열수, 천열수, 최천열수, 제노서멀 로 구분하며, 주로 금, 은, 납, 아연, 구리, 안티모니등 이 산출된다. (ko)
- Hydrothermal mineral deposits are accumulations of valuable minerals which formed from hot waters circulating in Earth's crust through fractures. They eventually create metallic-rich fluids concentrated in a selected volume of rock, which become supersaturated and then precipitate ore minerals. In some occurrences, minerals can be extracted for a profit by mining. Discovery of mineral deposits consumes considerable time and resources and only about one in every one thousand prospects explored by companies are eventually developed into a mine. A mineral deposit is any geologically significant concentration of an economically useful rock or mineral present in a specified area. The presence of a known but unexploited mineral deposit implies a lack of evidence for profitable extraction. (en)
|
