Mineralization Of The Zhibo Iron Deposit In Xinjiang Province

Zhibo large magnetite deposit lies to the east of Awulale metallogenic belt inXinjiang. On the basis of collecting previous data, a detailed study has been carriedout on the orefield geology, ore deposit geology and ore deposit geochemistry of thisdeposit, with a focus on analysis of its mineralizeation processs. Some significantachievements have been obtained in this thesis.Tectonically located at the northeastern margin of Ili block which isCarboniferous island arc belt, Zhibo iron deposit occurs at the northwestern margin ofcaldera. The occurrence of orebodies is controlled by the volcanic tectonic dome. Theore bodies of Zhibo iron deposit are hosted as stratiform, quasi-lamellar and lenticularforms in volcanic rocks of Carboniferous Dahalajunshan formation. The volcanicrocks are mainly basaltic andesite and andesite and belong to calc alkaline rock series.Zhibo iron deposit consists of some ore texture which can indicates its ore magmagenesis, such as sudden contact between massive magnetite and wall rock, brecciatedmagnetite provided with wall rock breccia, lath-shaped magnetite and flow structureof magnetite in Banded magnetite. Widely distributed of wall rock alteration showsthat hydrothermal metasomatism made a crucial contribution to mineralization. Zhiboiron deposit has two metallogenic periods (magma phase and hydrotherm phase)which can be divided in three phases: magnetite-diopside-epidote phase,magnetite-potash feldspar-epidote phase and quartz-sulfide phase. The rare earthelements and trace elements of magnetite ore and volcanic rocks have thecharacteristics of enrichment of LREE and LILE (such as K,Rb,Th) and depletion ofHREE and HFSE (such as Nb,Ta,Ti), their geochemical characteristics are similar toisland arc volcanic rocks. Basaltic volcanic rocks in Zhibo iron deposit are islandbasalts, which indicate that these rocks are probably formed in an island-arcenvironment. The consistency of rare earth elements and trace elements characteristicof magnetite ore and volcanic rocks imply that they are originated from the sameparent magma. Zhibo iron deposit is magmatic(main)-hydrothermal (minor)depositwhich is sourced from basaltic-andesitic magma.