Advances in Earth Science ›› 2010, Vol. 25 ›› Issue (2): 174-183. doi: 10.11867/j.issn.1001-8166.2010.02.0174

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Biogeochemical Characteristic and Mineralization Process of Sulfur during the Coal Accumulation Process in Early Paleozoic of Southern China

Yao Suping,Ding Hai,Hu Kai,Jiao Kun   

  1. School of Earth Sciences and Engineering, Nanjing University, Nanjing  210093, China
  • Received:2009-10-12 Revised:2009-11-19 Online:2010-02-10 Published:2010-02-10
  • Contact: Su-Ping YAO

Yao Suping,Ding Hai,Hu Kai,Jiao Kun. Biogeochemical Characteristic and Mineralization Process of Sulfur during the Coal Accumulation Process in Early Paleozoic of Southern China[J]. Advances in Earth Science, 2010, 25(2): 174-183.

The early Paleozoic coals were well-developed in southern provinces of China poor in coal resources. It was also known as “stone coal” due to being hard like rock. Stone coal was widely spread throughout southern China. Though the stone coal bed is discontinuous, the horizon can be recognized in a band of transitional shelf zone sediments stretching 1 600 km only across southern China from Zhejiang Province to Guangxi Province. There contains and sometimes enriches a variety of metal elements in stone coal. It has been found that as many as 60 species of associated elements such as vanadium, molybdenum, phosphorus, barium, nickel, uranium, gold, silver, etc. in stone coal up to now. Because some elements of the special enrichment can form industrial deposits in some areas, stone coal can be used as a single extraction of mineral resources and will have a great development potential to be multi-mineral resources. Researches show that stone coal formed in the marine reducing environment with abundant bacteria and algae bioaccumulation. A large number of fossils, such as bacteria and algae (e.g. Cyanobacteria and brown algae), acritarchs, the paleospore, the sponge spicules and a number of primitive fauna and flora whose categories are not clear contained in stone coal. Low carbon, high ash and high sulfur contents were the main characteristics of stone coal. The high sulfur quantity could be commonly interpreted as the marine sedimentary environment and the mechanical concentration and sequestration of algae. Most of the enrichment metal elements in stone coal are chalcophile. The early coal accumulation process is an important stage with enrichment of associated elements in stone coal. Polymetallic sulfides (e.g. sulfur, pyrite, chalcopyrite, sphalerite, vaesite, polydymite, dobschauite, millerite, blucite and jordisite, etc.) are the main occurrences of metal elements in stone coal. A large number of experiments and isotope data reveal that the bacterial sulfate reduction is the most likely biological agent, and it not only leads to the large-scale mineralization of metal sulphide, but also is the major coal and ore-forming mechanism of the stone coal and metal sulphide deposits, and apparently the biogeochemical behavior of sulfur directly impacts the occurrence and enrichment of the metal elements. But the conversion of sulfur biogeochemical processes and the relationship between the abnormal enrichment of metals and other basic geological and geochemical issues are not yet to be improved to solve during the early coal accumulation process. Therefore, further study of biogeochemical behavior of sulfur in the early Palaeozoic coal accumulation process, not only helps revealing the symbiotic mechanism and ore-forming effect of stone-coal bearing formation and polymetallic sulfide in South China, but also helps providing scientific basis for the formation mechanism of sulfur and the enrichment effect of metal trace elements in China′s stone-coal bearing formation. In addition, those researches could help providing the theoretical support for the extraction of rare metals in the stone coal, and also help providing scattered and precious metal materials in urgent need for the construction of China's national economy.

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