Dissertation > Astronomy,Earth Sciences > Geology > Of ore deposits > Deposit classification > Metal deposit ( Zonglun,)

Study on Fluid Inclusion of Tiemurt Pb-Zn(-Cu) Deposit,Altay

Author WangLinLin
Tutor XuJiuHua
School Beijing University of Science and Technology
Course Mineralogy,petrology, Mineral Deposit Geology
Keywords Tiemurt Altay Quartz vein Fluid inclusions Source of ore-formingmaterials
CLC P618.2
Type Master's thesis
Year 2009
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The Tiemurt deposit, located on the northeast limb of the Devonian Kelangvocanic-sedmentary basin, and on the northeast hanging wall of the regionalAbagong-Kurti Fault which marks the boundary between the Kangbutiebao (D1k) of lowerDevonian age and the Altai Formation (D2a) of middle Devonian age,occur in theKangbutiebao Formation which consists of acid volcanic rocks and volcaniclastic andcarbonic sedimentary rocks.The ore bodies,controlled by the second lithological unit ofupper Kangbutiebao Formation,occur in chloritized metamorphic siltstone and garnetchloritized marble.The ore minerals are mainly galena,sphalerite,chalcopyrite,pyrite andpyrrhotite,and the gangue minerals are dominated by quartz,actinolite,tremolite,chlorite,barite and carbonate.According to the geological survey and study on the specimens inhand,the Tiemurt VMS deposit can be divided into three stages.In early stage,sulfide isdisseminated,banded and massive.In middle stage,sulfide and white-gray quartz vein arebedding.In late stage,quartz vein which contains chalcopyrite shear the early layer.Three fluid inclusion assemblages (FIA) can be identified in vein quartz whichcountains chalcopyrite.The first FIA (FI0) consists of high salinity inclusions composed ofL-V-S inclusions (containing daughter crystals of NaCl) and L-V inclusions that aredistributed in an isolated or random fasion within single quartz grain.The second FIA (FI1)is a secondary CO2-H2O fluid inclusion assemblage and is composed of LCO2andLCO2-LH2O inclusions. The third FIA (FI2) is a carbonic(CO2-CH4)fluid inclusionassemblage which is composed of liquid CO2or CO2-CH4inclusions with minorLCO2-LH2O inclusions.They occur widely in vein quartz,distributed as oriented healedfractures,and usually cuts across the boundaries of the quartz grains and truncates the FI1fluid inclusions,and consequently represents a fluid inclusion assemblage from a latertectonic-hydrothermal event.Synchronic radiation X-ray fluorescence (SRXRF) analysis on the carbonaceous fluidinclusions from Tiemurt and the primary origin carbonaceous fluid inclusions fromSarekoubu deposit,which is a Late Carboniferous gold located near the same regional faultas the Tiemurt lead-zinc deposit,shows that the carbonaceous fluid inclusions fromTiemurt don’t countain elements such as Au,As which is closely related to gold mineralization while the primary origin carbonaceous fluid inclusions from Sarekoubuhave high content of such elements.It may be caused by the initial payment of goldenrichment during Early Devonian sedimentary volcanic.The Tiemurt was in low-layingdeep water,and did not has got the enrichment,so when the orogenic gold deposit such asSarekoubu formed(±320Ma),the carbonaceous fluid didn’t bring in the superposition ofglod for Tiemurt.The rare earth elements and trace elements in the carbonaceous fluidinclusions from Sarekuobu are higher than those from Tiemurt.The δ34S of disseminated ore is-26.46-25.38‰,and shows it’s rich in32S,whichmeans relation to the reduction by the bacteria from the seabed.The δ34S of vein sulfide isclose to meteorite,and shows hydrothermal activity caused by tectonic movement impactthe deposit.The lead isotope is206Pb/204Pb=16.8618.06,207Pb/204Pb=15.4215.61,208Pb/204Pb=37.2738.07.It shows stability in the composition of lead,and it has thecharacter of pure source from deep in earth.The lead isotope also shows normal lead,andits projection is located in the area between upper crust and orogenic belt or orogenic beltand upper mantle.It is speculated the lead is from mantle or deep-crust.

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