Font Size: a A A

The Study For The Nixiong-type Iron Deposit And The Regional Metallogenic Regularity Of Iron And Copper In The Middle Gangdese,Tibet

Posted on:2013-02-25Degree:DoctorType:Dissertation
Country:ChinaCandidate:S H CaoFull Text:PDF
GTID:1110330371982241Subject:Mineralogy, petrology, ore deposits
Abstract/Summary:PDF Full Text Request
The middle Grandise in Tibet is the important component of the Gangdese metallogenicbelt in the Qinghai-Tibet Platean, which was studied geologically in obviously lower degreethan the southeastern Gangdese. This time, three new iron-ore bodies have been confined inthe Gunjiu mine of the Nixong iron ore field in the Cuoqin County through carrying out thegeneral survey projects from the Middle Fund of Geological Survey and other mineralprospecting projects. The Fel main iron-ore body has a length of over 1000m, thicknessesfrom 7.49m to 72.76m, tenors of 35.56%-49.33% mFe in its iron ore and an estimation ofmore than 51 million tons of 333+334 rich iron-ore resource. Moreover, a series of Fe, Cupolymetallic deposits (ore occurrences) with medium-sized and greater scales potentialshave been found in the Nixong ore field and around it, in which there are great prospectingpotentials and which is also regarded as the ideal area serving as the national base ofsuperseding iron and copper resourcesThe main results and knowledge are summarized as follows:1.By studying the representative deposit, the wallrock alternation in the Gunjiuskarn-type iron deposit in Nixong is divided into five zones as the alternation zone inside theintrusive body, the inner skarn-magnetite zone, the outer skarn zone, the marmorizationzone and the pyritization-hornfels zone. As there is distinctly short of albitization in theGunjiu iron deposit, it is considered that its mineralization and alternation characteristics aredifferent from that in the representative skarn-type iron deposits (as Day-type iron deposits) inChina. Furthermore, the mineralogical features of the skarn and the geochemical features ofthe deposit were preliminarily studied.2.The precise SHRIMP U-Pb Zircon Dating of the granodiorite and admellite involvedin the Gunjiu iron deposit forming resulted in respectively an age of 119.90±1.9Ma and anage of 116.9±1.7Ma. Combined with the comprehensive analysis of the deposit genesis, it isbelieved that its mineralization and diagenesis are the same geological process and itsmetallogenetic epoch is Early Cretaceous Epoch.3.The author preliminarily established the metallogenic model and deposit model of theNixong-type skarn iron deposit in the Gangdese metallogenic belt and the regionalmetallogenic model in the middle Gangdese, Tibet. The author also summarized variousprospecting indications in geology and geophysics, which can be used in indicating furthergeological prospecting.4.The article systemically summed up the regional metallogenic regularity in the middleGangdese, which is redivided into fiveⅣ-level metallogenic subzones and twenty-twoⅤ-level prospects. It was pointed out that the middle Gangdese is situated between the southGangdese metallogenic belt and the Bangong Co-Nujiang tectonic- metallogenic belt studiedin higher degree and so it is a join and of great significance in studying the metallogenicregularity. However, this area was surveyed in extremely low degree, so the articlepreliminarily filled up the blank in the research of the regional metallogenic rules in the middle Gangdese.5.The article described the mineralization characteristics of five metallogenic zones andsix main prospects in the middle Gangdese and estimated the potential of iron and copperresources in the middle part of the Gangdese metallogenic belt. The proposed prospects showclearly the direction for the future project approval and survey of the Middle Fund ofGeological Survey.6.On the bases of the features of deposits (ore occurrences) found newly and thespace-time distribution of various types of mineralization in the middle Gangdese, twometallogenic series and six metallogenic sub-series have been preliminarily distinguished.Among them was firstly defined the metallogenic sub-series of iron deposit involved in theintermediate-acid intrusive rock of Early Yanshan Period, pointing out the new direction toprospect older deposits than the Nixong iron deposit in the the middle Gangdese, Tibet. Thepreliminarily definition of the metallogenic series of copper polymetallic deposit associatedwith porphyry of Himalayan period proves that the porphyry-type copper ore belt in thesouthern Gangdese probably extends from east to west, and likely stretches into the middleGangdese, expanding the area for prospecting porphyry-type copper deposits.
Keywords/Search Tags:the Middle Gangdese, Nixong-type Skarn Iron Deposit, Metallogenic Series, Metallogenic Regularities, Deposit Model
PDF Full Text Request
Related items