Geochemical anomaly pattern in the Liuju Sandstone-Type Copper Deposit, Yunnan, China
|Location||International Geological Congress,oslo 2008|
|Author||Wu, Peng; Han, Runsheng|
|Holding Date||11 October 2008|
The Liuju copper deposit, one of the typical sandstone-type copper deposits, is located in the Upper Cretaceous continental sandstone basin of Chuxiong, Yunnan Province, China. From purple bed to grey bed in K2ml1, the ore minerals follow the law of hematite, chalcocite, bornite, chalcopyrite and pyrite. Based on geochemical datum of 9 drills in this deposit, the features of major elements and trace elements show that the ore-forming elements association is Cu, Ag, As, Sb and Hg. The axial zonation of indicator elements in K2ml1from top to bottom is V, Ni→Cu, Ag, Hg, As, Sb→ Pb, Zn, V, Ni and the lateral zonation from purple belt to grey belt is Sb→Hg→V→Cu, As, Sb→Ag, Co, Ni→Pb→Zn. The geochemical anomalous pattern has been established, that is, the anomaly of Co, Ni, and V appears above the ore bodies, the anomaly of Pb, Zn under the ore bodies. The anomaly of Cu, Ag, As, Sb, Hg and the ratio of Cu/Ag>315, Cu/(Pb+Zn)>320, Cu/(As+Sb+Hg) 1000-5800 are concomitant with rich ore bodies; the anomaly of Pb, Zn, Co, (Ni) and Cu/Ag<105, Cu/(Pb+Zn)<7, Cu/(As+Sb+Hg)<36 implies barren. The contents of Cu, Ag, As, Sb, Hg and the ratio of dual elements reduce longitudinally, and it shows that the copper minealization becomes weaker or the position of the ore body is displaced.
It has been showed from the pattern that chalcocite; bornite and chalcopyrite were disseminated mainly in the grey bed. It may suggest that chalcocite precipitated originally in the grayish sandstones and was removed during the reddening of the rocks. The pattern is an important accordance for the depth ore-forming prognosis. It indicates the extension direction of deep-seated ore body, and whether the drill location near to ore body or not. The correctness of the research results has already proved and shall continually prove by the practical applications in the mine. * Granted jointly by the funds for Program for State Special Ore-finding Project for Resource Crisis Mines (200453001), NCET in University (NCET-04-917) and Project for the Distinguishing Discipline of KUST (2008).