Research On The Metallogenic Series Of Gejiu Tin-polymetallic Deposit

The doctoral dessertation title of Research on the Metallogenic Series of Gejiu Tin-polymetallic Deposit is selected based on the cooperative item of Yunnan province and China academy/university of research on the reserves increase and the prediction of deposits in the periphery and deep of Gejiu tin deposit (serial number:2000YK-05). The many researches on the section survey or mapping of the stratum of Gejiu formation and basalt; the petrology, petrochemistry and geochemistry analysis of the stratum of Gejiu formation, basalt and granite and the.area geological synthetically study; the study of the geological characteristics of the deposit, the mineralogy, texture and structure of ores; the systematically study of the microelement, rare earth element, stable isotope and fluid inclusion and so on of rock or ore have been done. And the following conclusions have been drawn:No.l The non-granitic mineralization has been systematically and completely studied firstly. In Gejiu diggings, the seabed basic volcano-sedimentary mineralization and the seabed exhalative hydrothermal sedimentary mineralization of the medium-later Indo-Chinese epoch other than the granitic mineralization of late Yanshanian epoch do exist.No.2 Through the study of the regional ore-forming geological background and the characteristics of the deposits in the diggings, the author think that the ore-forming materials come from the old basement of Precambrian system, Cambrian System, Devonian System, the carbonate rocks and the alkali-basalt of Gejiu formation in Middle Triassic Series, the granites of late Yanshanian epoch etc. Gejiu tin-polymetallic deposit has many mineralization stages and periods. It is a poly and compound genesis deposit.No.3 The author has put forward a new viewpoint about deposit metallogenic series and applied the theory in Gejiu diggings firstly. He thinks that the study object of metallogenic series is the combination of all types of deposits that have genetic relationships. These geneticrelationships are at least about mineralization(igneous processes, sedimentary processes and metamorphic processes etc.), time( metallogenic epoch, metallogenic stages, ore-bearing strata etc.), space(structure geological background, ore-bearing formation ect.) and metallogenic materials(the major metallogenic element, the composition and source of the metallogenic material etc.). In the viewpoint of system theory, the author has studied the metallogenic structure evolvement, mineralization, metallogenic epoch, the deposit geochemical genesis type, the shape and distribution of the orebody, the position of the orebody and the characteristic of the wallrock, the texture and structure of ores, mineral combination, the characteristic of the microelement, rare earth element and stable isotope of the rocks or ores, the mineral control laws and the deposit genesis model. And the author points out that the metallogenic series study of Gejiu diggings not only can break through the metallogenic theory, but also can guide the mineral prospecting for mine. The conclusion has been proved by the practice of prospecting.No.4 According to the mineralization, deposit genesis, the deposit geological characteristic and the geochemical types of the deposits, the author plots out twelve deposit types. They are massive sulfide copper tin zinc deposit, massive sulfide copper gold deposit, massive sulfide tin lead deposit(intrafolial oxide deposit), stratiform sulfide lead zinc deposit, tin-bearing dolostone tin lead zinc deposit, tourmaline thin vein tin tungsten bismuth deposit, greisen tin tungsten deposit( ore-bearing granite), the sulfide tin lead zinc argentine deposit from fault belts, skarn sulfide tin copper zinc deposit, residual slopping sedimentary placer, flood placer and cave accumulation sand deposit. The deposit classification consummates intrinsic classification project.No.5 Four deposit metallogenic series are made certain in Gejiu diggings. From the early to the late, the genetic sequence is approximately the seabed basic volcano-s...