The Study of Chlorite at Dajing Deposit in Innrer-Mongolia of China

Abstract:

Chlorite widely occurs in the alteration halo of hydrothermal deposits, it has been found in the alteration rocks of tourmaline-sericite-quartz, quartz-chlorite-hydrosericite and carbonate in Dajing Deposit. These rocks are adjacent to the ore body. The chemical composition of chlorite is complicated. After study the chlorite composition in Dajing Deposit as well as other deposits with same type worldwide, it is discovered that the ferriferous coefficient [Fe/(Fe+Mg+Mn+Ca)] of chlorite can be used as indicator for various metal assemblages in ore deposits.Chlorite in Dajing Deposits has an assemblage of Ag-Cu-Pb-Zn,which is high for ferriferous coefficient. While chlorite in Kwaisin and Cibai of Russia has the assemblage of Pb-Zn(where Zn is dominated)which contains species with low ferriferous coefficient. There is a positive correlation between ferriterous coefficient of chlorite and its occurring elevation. This is resulted from the variation of the activity of Fe and Mg, the acidity and alkalinity of solution in different elevation and deposits. Besides that, parameter b₀ of unit in chlorite also shows positive correlation with its occurring elevation in Dajing Deposit and b₀ is larger in shallow than that in depth. This is contributed to the closest-packed structure under the condition of high pressure.

Key words:

Chlorite; ferriferous coefficient; b₀ of unit cell; occurring elevation

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