内蒙古自治区胜利煤田锗矿地质及分布规律

介绍了胜利煤-锗矿床的地质背景,以及锗在矿层的分布情况.胜利煤田处于二连盆地东端乌尼特坳陷中,为一宽缓向斜,地层平缓.胜利煤田煤-锗矿床发育于早白垩世断陷盆地内,位于二连盆地群中胜利煤盆的西南一隅,富锗矿层的分布受两侧F1,F2断层影响,呈现南部埋藏浅厚度薄、北部埋藏深厚度大的倾斜状特点;锗品位变化为南、北部较高(>400×10-6),东、西部较低(200×10-6左右)的"鞍"状分布特点,而向盆地中心急剧降低.沿煤层纵向上可以出现多个聚锗高值,个别钻孔煤层下部夹矸锗含量超过工业品位而具有工业价值,而煤层顶、底板锗含量都很低(<10×10-6),不具有工业价值.锗的分布,与成矿古地质、环境变化有关,受沼泽微环境和水动力影响,锗在煤层中的富集出现波动.采用"地质块段法"估算锗煤的资源量,资源量估算面积1.097 5 km2,估算结果锗资源量1 805 t.

Coal petrology and genesis of Jurassic coal in the Ordos Basin,China

Multiple sets of thick coal beds characterized by simple structure and shallow burial depth were developed in the Early and Middle Jurassic strata of the Ordos Basin, northwestern China. The huge reserves of this high quality coal have a high commercial value. We studied the coal＇s petrologic characteristics and its maceral distribution to determine the maceral＇s contribution to generation of oil and gas. The results show that the Jurassic coals in the Ordos Basin have special petrological features because of the Basin＇s unique depo- sitional environment which was mainly a series of high-stand swamps in the upper fluvial system. These petro- graphic features are a result of the development of typical inland lakes where some sand bodies were formed by migrating rivers. After burial, the peat continued to undergo oxidizing conditions, this process generated extensive higher inertinite contents in the coals and the vitrinite components were altered to semi-vitrinite. The macroscopic petrographic types of these Jurassic coals are mainly semi-dull coal, dull coal, semilustrous and lustrous coal. The proportions of semi-dull coal and dull coal are higher in the basin margins, especially in the area near the northern margin. The numbers of semilustrous and lustrous coals increase southwards and towards the central basin. This situation indicates that different coal-forming swamp environments have major controlling effects on the coal components. Another observation is that in the Ordos＇ coal sequences, especially in the lower part, some sandstone beds are thick, up to 20 m with a coarse grain size. The higher fusinite content in the macerals accompanies a higher semi-vitrinite content with more complete and regular plant cell structure. The fusinite structure is clear and well preserved. After burial, the lithology of the roof and floor rocks can continue to affect the evolution of coal petrology. The sand bodies in the roof and floor exhibit good physical conditions so that pore water can maintain a long-term state of oxidation, circulation and connection to the coal. So coal components remain in an oxidation environment for a long time. Conversely, in the basin center, lacustrine facies developed and peat was rapidly covered by mudstone after burial and subsequent coal beds rapidly entered a reducing environment. As a result, abundant gelatification occurred and the vitrinite content increased. E^inite often accumulated in a specific position in the coal bed. Although the average exinite content is not high on the whole, it does significantly contribute to the total hydrocarbon generation. The exinite content has been underestimated, especially the amorphous bituminous fluid and its importance is emphasized here. The reason is that the fluid flows easily into fusinite which has strong rigidity, or flows into some fissures, where it is commonly neglected.

Guizhou Province, China: the birthplace of modern Medical Geology

Medical Geology,the emerging discipline that focuses on the health impacts of geologic materials and geologic processes,has its roots in Guizhou Province,China.In the 1980 s Prof.Zheng Baoshan and his students recognized that a large number of people in Guizhou Province had clinical symptoms of arsenic poisoning,fluorine exposure,selenosis,and other diseases caused by exposure to potentially toxic trace elements or due to deficiency of essential elements.Their publications and invitations to scientists to visit the Province ultimately resulted in increased attention to the health impacts of the natural environment and the formation of scientific societies,the publication of at least a dozen books,and thousands of technical articles on what is now called Medical Geology.

The future environmental and health impacts of coal

In the United States,coal consumption in the last 12 years has declined from 1,045,140 million short tons in 2007 to 539,420 million short tons in 2019,a decrease of almost 50%.During that period the number of electric power coal generators has declined from 1,470 to 738 accounting for 21%of capacity.An even more dramatic decrease in coal use has occurred in Western Europe.This significant reduction in coal use and the concomitant closure of coal mines and coal-burning power plants will result in substantially cleaner air,reductions in respiratory problems such as asthma,less heart disease,fewer hospitalizations,and other health benefits,as well as a reduction in occupational health problems such as silicosis and Coal Workers’Pneumoconiosis(Black Lung Disease).However,in China,India,Russia and in several other Asian countries some projections indicate an increase in coal production and use.In some situations,the coal is burned in old,highly polluting power plants.In these regions the health impacts of coal use could worsen.In addition,millions of people in these regions still burn coal in their homes resulting in maximal exposure to the pollutants such as arsenic,selenium,fluorine,and mercury released from coal combustion.

Distribution of rare earth elements in PM10 emitted from burning coals and soil-mixed coal briquettes

Emission from burning coals is one of the major sources of the airborne particles in China.We carried out a study on the rare earth elements(REEs)in the inhalable particulate matter(PM10)emitted from burning coals and soil-coal honeycomb briquettes with different volatile contents and ash yields in a combustion-dilution system.Gravimetric analysis indicates that the equivalent mass concentration of the PM10 emitted from burning the coals is higher than that emitted from burning the briquettes.The ICP-MS analysis indicates that the contents of total REEs in the coal-burning PM10 are lower than those in the briquetteburning PM10.In addition,the contents of the light rare earth elements(LREEs)are higher than those of the heavy rare earth elements(HREEs)in the PM10 emitted from burning the coals and briquettes,demonstrating that the REEs in both the coal-burning and briquetteburning PM10 are dominated by LREEs.The higher contents of total REEs and LREEs in the coal-burning PM10 are associated with the higher ash yields and lower volatile contents in the raw coals.A comparative analysis indicates that the La/Sm ratios in the PM10 emitted from burning the coals and briquettes,being lower than 2,are lower than those in the particles from gasoline-powered vehicle emission.