Study On Element Geochemistry Of The Manpai Tungsten Deposits,Myanmar

The Manpai tungsten deposit is a large non-tin tungsten deposits in Myanmar.It is significantly different from the tungsten-tin deposits in symbiosis in the Binlang, Mergui and Tavoy large tungsten-tin mining fields, Central Myanmar. Even such a tungsten deposit is also rare in southern China. Therefore, Study its element geochemical characteristics of the rocks and minerals is of great important scientific significance.This author is in closed connection with China-Myanmar cooperation projects and takes the deposit as a research objet,and trying to research causes of the deposit by studying elements geochemical characteristics of the rocks and minerals. For this reason,Major elements,REE and trace elements of the granites,porphyry, greisenes and quartzs of tungsten-feraing is tested by chemical methods,ICP-MS,ICP-OES and X-ray fluorescence respectively. On the basis of the obtained data were standardized and related analysis,the results of standardized data processing and the tungsten mineralized characteristics are researched comprehensively. The study includes: Regional geological-tectonic background; mining geological structures; tungsten mineralized characteristics; element geochemistry;W and Sn mineralized separation and controlling factors and so on. Through these studies, the following conclusions:1. The Manpai tungsten deposit,Myanmar,is formed between granite magma genesis evolution and is a close associate. The tungsten deposit is formed in the gas-hydrothermal processes and hydrothermal processes late granitic magma diagenesis processes. The tungsten mineralization is the result of strong greisen and hydrothermal processes.2. The study results of the granitic magma diagenesis processes showed that the points of granite samples fall within the scope of I-type granite in Ce-SiO₂ diagram. This shows that the granites should belong to metaluminous calc-alkaline granites. The points of the samples fall within “Non-orogenic A-type granites region” in the Batchelor R2-R1 granite genetic classification illustration. This indicates that the output of granite tectonic setting is a large rift zone.3. REE in the evolution process of magmatic hydrothermal,ΣREE tends to decrease,LREE decreased,HREE is switch to rise from lower. As can be seen from REE differentiation parameters that LREE and HREE appear there is clear differentiation. This shows in the evolution of magmatic hydrothermal, LREE is a loss, but HREE is enriched. On the other hand it showed that the evolution of magmatic hydrothermal has a long process, which is conducive to aggregation of gashydrothermal and high aggregation of tungsten until mineralized it.4. Trends can be seen from the trace element contents, the contents of tungsten is increased stability from greisenization stage to hydrothermal stage. It is from preliminary enrichment up to highly enriched to ore-forming deposits. Conversely, the tin is manifested as a continuous double reduction. The opposite trend show that tungsten and tin mineralized separation may occur in the evolution process of magmatic hydrothermal and ore-forming process.5. And the reasons of tungsten and tin mineralized separation, in addition to the geochemical behavior of tungsten and tin, but also the compositions of hydrothermal system and its properties of low-sulfur and oxygen-rich. According to this speculation, the mineralized hydrothermal system may be ore-forming hydrothermal system to have a high oxygen fugacity and lower sulfur fugacity. This feature is clearly in favor of the formation of wolframite and scheelite, and not conducive to the formation of cassiterite. This is the reasons only formed tungsten deposit without formed tungsten-tin deposits.Made major innovative achievements are as follows:1. The tungsten-bearing granites in the Manpai area of Myanmar is metaluminous calc-alkaline granites by first identified. And it is the A-type granites in the formed in non-orogenic areas. And the granites output tectonic setting is a large rift zone.2. Unlike the tungsten-tin deposits in symbiosis in the Binlang, Mergui and Tavoy large tungsten-tin mining fields,Central Myanmar. The tungsten deposit was the result caused by tungsten and tin to occur with mineralized separation in the mineralized process.3. The authors note that the reasons of tungsten and tin mineralized separation, in addition to the geochemical behavior of tungsten and tin related,but also the compositions of hydrothermal system and its properties of low-sulfur and oxygen-rich. According to this speculation, the mineralized hydrothermal system may be an ore-forming hydrothermal system to have a high oxygen fugacity and lower sulfur fugacity.