Characteristics And Formation Environment Of Chloritization In Shazhou Uranium Deposit

Xiangshan uranium orefield was one of the most mportant uranium orefield which thereserve was proved and being exploited in china currently.Chloritization was one of themost extensive development hydrothermal alteration in Shazhou deposit before and duringthe uranium mineralization, Mining has proven that Chloritization-uranium-Ore not onlyan important supplement type of the traditional silicon-ore types but also a type ofhigh-grade ore. Papers based on the data of regional geological background, geologicalcharacteristics in Shazhou deposit, field geological investigation, indoor microscopicobservation, electron microprobe analysis techniques and a track etch test method,discussed the distribution characteristics within the scope, and determine the Chemicalcomposition of chlorite. And explore the chemical classification of the chlorite, theeigenvalue of chlorite n (Mg)/n (Fe+Mg), nAl/n (Al+Mg+Fe), AlIV, n (Fe)/n of (Fe+Mg), and the relationship between them to further. And then calculated the formationtemperature of chlorite, explored the formation of green ore environment, formationmechanism and the chlorite relation with uranium mineralization.Obtained the following understanding:(1) There are four Occurrence types of Chloritedistributed in Shazhou deposit: First, a pulse distribution of chlorite; second, Chloritedistributed in the rocks either in pseudomorph of biotite; Third, the Chlorite altered andclose symbiosis with feldspar; Forth, the chlorite symbiosis closely with the Pitchblende.(2)The magnesium and iron changed greatly in chemical composition of chlorite; Chloritemainly Including chamosite and compacted chlorite. Most of the chlorite originatedargillaceous rocks. Only partially come from the fluid which riched in iron andmagnesium.or influence by the fluid which riched in iron and magnesium in the process offormation.(3)The formation temperature varied in169～219℃. Focued in this range of 200~209℃, the average temperature was200℃, which belongs to the low temperatureunder the conditions of the formation;(4)The chlorite formed under reduction condition:Dissolve-precipitation and dissolve-transfer precipitation were the formation mechanism.(5)The track etching experimental results showed Chlorite relationship with uraniummineralization which maily reflected in two aspects: one was in the water-rock interactionprocess, biotite altered to chlorite and make the inert uranium relseased as activity uraniumwith the way of isomorphism. Two was that the activity uranium in the thermal fluidmigrated with the hydrothermal to the proper position of precipitation partly. There was apart of uranium adsorption by the new generatin of chlorite.