Application of remote sensing to seeking blind ore deposcts in the middle lower reaches of Yangtze River
Reconstruction of new models for the ore deposit series based on deep magmatic thermo-dynamic metallogenesis theory.
It is obvious that recent geological survey and mineral exploration will not be conducted until the mineral deposit formation models have been established on the basis of sufficient geology and exploration data, mining records, mineral deposit studies and large quantities of new geology and mineral deposit information. Among them, the comprehensive introduction of remote sensing data, geochemical and geophysical data is remarkably helpful. It is with this understanding that a careful integration analysis has been made for the ore deposits and ore locations in the middle lower reaches of Yangtze river, based on remote sensing information related tot eh large number of orebelts, orefellds, ore-districts and ore deposits in this region combined with present geological, mining, geophysical and geochemical data. The result has shown that here exist ore deposit of large size, high grade and rich in useful components in this region. Most of them are ore liquid hydrothermal filling deposits, i.e. deposits of deep magma pump origin.
These deposits attribute their formation to the deep hear sudden concentration, pneumatic transportation, penetration and impact subsurface expansion and fissure space expansion within the petrogenetic passageways of the magma. They are characterized by : a deep ore-rich magmatic heat root, i.e. a magmatic thermal chamber (store), a relatively fixed petrogenetic and metallogenetic passageway, a group of pipe-like magmatic soil-liquid-gas carriers which emit upward flows intruding, along the nearly vertical linear space, form deep lithosphere and even upper mantle into the surface or subsurface of the crust. These are just what we have located : round-shaped structure, small deep rock body, volcanic passage, small subsurface explosion dome, magmatic peak stock, pipe, thorn and thermal impact pipe, with a diameter less than 5 km.
Fig. 4 Cycle Structrue & Ore Deposit Distribution in Nanjing-Zhenjiang Area, Jiangsu
They are located in the centers of large magmatic protrusions (pillars) as well as certain parts of the peripheric futl zones as shown in Fig.4along such vertical metallogenetic passageways magma encouraged by the decrease gradient of temperature and pressure, open its way in the ore-storing space, resulting in metallognetic series with horizontal and vertical subzones. And such metallogenetic series is represented in different depth by as shown in Fig 5, magmatic segregation type, porphyry type, vienlet impegnation type, ore-liquid filling type, hydrothermal type, layer-following or layer penetration vein type, volcanic gailquid type, contact metasomatic type, volcano sedimentary type, sedimentary type, thermal concentration type and secondary concentration type. These types are in sequential transition while skarn, as a special type, cannot form ore alone (Fig 6). These cadied haws on a stick deposits some times may differ in mineral content, but in the other time they may have the same minerals. Such kind of high temperature high-energy metallogenesis or catagensie has no rigid requirement and selection for ore source formation. Since the extraction of ore material takes place I a very deep and huge magmatic stove, the very high thermal energy alone is capable of making rich ore-liquid from the magmatic complex with the value approximate to Clerk. In addition, this kind of metalogensie, mainly in the form of deep ore-liquid injection, has no special requirement for the country rock as the outflow, emitted by the ore carrier, can crate space on its own, and it has no strict requirement for consolidated surface shallow crust. Therefore, it is an independent high energy system with extremely strong intrinsic structure and geometry, quite different from the concept proposed by traditional geology and multi-compoent blind ore deposites. This kind of high thermal energy metallogenesis is very powerful, not only controls the formation of mineral deposits, but catastaphe. It is for this reason that this theory is referred to as marshal law of geology, or arbitrary decision-making model. This theoretical model enjoy high capability of prediction and economic benefits by rapid inference and high efficiency. Metallogenetic thermo-dynamic passageways of its kind has proved to be stable since Indo-China and Yanshan movements, acting as successive movement during 100,000,000 years.
Someof the thermal structures worked until Cenozoic, and even today, geological catastrophes and other natural disasters are excised and controlled by thermo-dynamics, such as Liyang earthquakes in 1979, South Yellow Sea-Shanghai earthquake in 1982, Changshu earthquake in May 1990, Taihu floods and migration of Yangtze River mouth. The metallognetic series, however, requires careful analysis because of the repeated stacking ore formation and destructive impact along the ore-forming passageway. It is believed that the metallogenetic model produced by remote sensing geology is suitable not only for the middle-lower reaches of Yangtze River, but also for other regions. For the convenience of application, a comprehensive geological model has been established (see fig.6), which represents ore deposits of the closed type central metallogenetic passage.
