Research On Mineralization Of The Xianghualing Tin Polymetallic Deposit, Hunan Province, China

Xianghualing tin polymetallic deposit is a large tin-based polymetallic deposit in Nanlingtungsten-tin mineralization belt. It lies in the central segment of the Qin-Hang junction zone andnorth-center of the east-west tectonic-magma-minerogenic belt. Despite of different types ofmineralization, numerous mineralizing elements and complex mineralization, it is also a idealdeposit to study its mineralization. In this paper, we study its mineralization by using Petrology,Mineral Deposit Geology, zircon U-Pb Chronology, Geochemistry and Isotopic Geochemistry.Finally, we discuss its ore-forming process, define its minerogenic geological body and develop itsmineral prediction model. The main conclusions are listed as follows:(1) This paper study out that the Laiziling granite and its concealed rock body should becalled siderophyllite alkalic feldspar granite. And the granite has characteristics of high silica,alkali-rich, aluminum supersaturation, poor in Fe, Mg, Ca, rich in ore-forming elementsabundance, and it has a nearly horizontal “V” type REE pattern characterized by higher∑REE,higher LREE, and clear negative Eu anomalies. All the characteristics indicate that the granite inXianghualing belongs to crust remelting type and highly fractionated granite.(2) The LA-ICP-MS zircon U-Pb dating indicates that the concealed granite of Xinfeng oresection (150.37±0.94Ma, MSWD=0.113), the albite granite (151.18±0.91Ma, MSWD=0.14), andthe granite porphyry (151.18±0.91Ma, MSWD=0.14) intruded in late Jurassic. Consistent withthe ages of Xianghualing tin polymetallic mineralization，we indicate that they may occur in thesame tectonic-magma activities at late Jurassic.（3）The tin body which was known as a basal conglomerate type tin body should be a skarntype tin body controlled by formations. Thus, the derection for tin search is clear.（4）We discussed the mechanism of mineralization. Sources of ore-forming materials mainlycome from the magma in Xianghualing. And sources of ore-forming fluids are mainly derivedfrom the magmatic water at early stage of mineralization and a mixture of rain water andmagmatic water at the late ore-forming stage. Finally, we define its metallogenic geological body,mineralization structure and discontinuity, mineralization characteristics, and draw the geologicalmodel for prospecting prediction.