Font Size: a A A

Characteristics And Genesis Of The Kendekeke Polymetallic Deposit, Qinhai Province

Posted on:2011-08-21Degree:MasterType:Thesis
Country:ChinaCandidate:M HuangFull Text:PDF
GTID:2120360305494585Subject:Structural geology
Abstract/Summary:PDF Full Text Request
Kendekeke polymetallic deposit, located in the southwestern margin of the Chaidamu Basin-the Caledonian volcanic basin in the middle part of the tectonic fault depression zone of Qimantage back-arc of the Tarim-Chaidamu plate, is one of the most valuable deposit which has been discovered recently in Qimantage area. The geochemistry, fluid-inclusion petrography, micro-thermometry, and component analysis were used to research on rock-forming and metallogenic mechanisms, characteristics of ore-forming fluids, genesis of deposit, mineralization and etc., based on regional geological setting and geological features of the deposit.According to study, the deposit mainly has 4 mineralization periods: hydrothermal exhalative sedimentation period, skarnized hydrothermal activity period (include skarn-stage, oxide stage and sulfide-stage), late tectonic hydrothermal activity period and hypergene oxidation period. There are various characteristics of inclusions at different stages. The size of inclusions mainly varied from 4 to lOμm, with maximum size of 40μm. Most of inclusions are ellipse in shape and a few have a negative crystal shape. Three types of fluid inclusions have been recognized according to the different characteristics:aqueous, aqueous-CO2, and rarefied CO2 vapor inclusions.The gas phase is mainly composed of H2O and CO2, with minor organic gas; the main anions in the liquid composition are Cl-, NO3- and SO42-, the cations are Ca2+, Na+and K+. The ore-forming solutions belong to the CO2-Ca2+(Na+, K+)-Cl--(SO42-,F-)-H2O type.The ore-forming solution of the first stage, which originated from magmatic hydrothermal fluid, is characterized by high salinity (19-25wt% NaCl equiv), high density (0.817-1.033g/cm3), and high temperature with a wide variation range. The ore-forming solution of the second stage is medium-low-salinity (1-12wt% NaCl equiv) and medium-low-density (0.632-0.982g/cm3), mainly originated from mixed water, especially the mixture of groundwater and magmatic water or the underground thermal brine, and the transition of temperature changes from high to low. The immiscibility of CO2 made a large amouts of CO2 separate from the fluid during this stage what played a good role in superposition and enrichment of mineralization of partial metals.
Keywords/Search Tags:fluid inclusion, geochemistry, mineralization, deposit genesis, Kendekeke polymetallic deposit
PDF Full Text Request
Related items