College of Earth Sciences �� Technology��Southwest Petroleum University��Chengdu 610500��China

Ore- bearing gabbros and ore- free basalts from Panzhihua��Sichuan are compared in this article u- sing lithology and petrogeochemistry methods�� The results show that the ore- bearing gabbros are proved to be pera- luminous calc- alkali rocks��rich in Ti�� However��the ore- free basalts belong to metaluminous calc- alkali rocks�� showing high Mg and low Ti�� The differences in trace elements and rare earth elements are obviously�� The former has low ��EE��a positive anomaly in Eu and common fractionation between light and heavy ��EEs��while the latter appears higher in ��EE��with a weak positive anomaly in Eu and sharp fractionation�� Compared to primitive man- tle��incompatible elements in basalts are higher��especially strong incompatible elements such as ��b��Ba��Th�� Nb��La��Ce��Sr��accumulate 50 ��100 times relatively�� Combined with previous study��it is found that the Pan- zhihua ore- bearing gabbros and Ertan ore- free basalts may be derived from a different extent of partial melting of en- riched mantle��and then are contaminated with crust materials during magma evolution�� The authors propose that crystalization fractionation of magma��contamination with crust materials and retain of volatiles might be the vital controlling factors for gabbro intrusion to form the V- - Ti magnetite deposit��