Geochemical Relationship Between Tin Mineralization And A-type Granite

The Furong tin orefield is located in the southern part of the Qitianling granite complex, Hunan Province, China. It is a part of the Chenzhou-Lanshan NE-trending W-Sn-Pb-Zn mineralization belt. Based on the detailed studies on the regional geology and the local geology of the orefield, the typical samples were selected for systematic microscopic observation and fluid inclusions studies. Meanwhile, the mineralization time, the trace elements, rare earth elements and the isotopic compositions(S, Pb, He) of the ores or rocks have been analyzed. Based on these data, the relationship between the Qitianling A-type granites magmatic activity and the mineralization, the sources of the ore-forming materials and fluid have been discussed. Finally, a possible genetic mechanism was proposed. The main conclusions are listed as follows:(1) The Furong tin orefield, spatially and temporally associated with the Qitianling granites, is a newly-discovered tin orefield. It has an advantaged geology setting, large scale, high ore grade and good prospecting potential. All samples of the Qitianling granites are distributed in the range of A2 type granite. So the orefield is a newly-discovered tin resource. However, the studies for this sort of tin deposits are still scared at present.(2) The Furong unit granite is emplaced at 158-160Ma. This studies have shown that the main tin-mineralization of the orefield occurred 150-60Ma ago, and this is consistent with the intrusion age of the Qitianling granite complex. This stage just is the time that there have a lot of large-scale deposits formation in the Southeast China because of the...