An ultramafic-alkaline intrusion-hosted magnetite-apatite deposit, northern margin of north China craton
The early Mesozoic Fanshan ultramaficalkaline complex is situated at the northern margin of north China craton and consists of three zones from its core to margin (zones 1-3). The middle zone (zone 2) is the oldest intrusive phase with a composition of ultramafic. The outer zone (zone 3)and inner zone (zone 1) have a composition of alkaline. Three zones have essentially same mineralogical assemblage, but the zone 2 is distinct in its compositional layering. The magnetiteapatite orebodies occur in middle part of zone 2,which comprises two or three layers mainly consisting of apatite or magnetite-apatite, the apatite layer being less than 3 meters thick, the layer consisting of magnetite-apatite about 7meters thick. The composition of clinopyroxene and biotite in the rocks shows a magmatic evolutionary trend.Whole major element variations of the rocks are consistent with the crystal fractionation dominated by clinopyroxene, magnetite and apatite. All rocks in the Fanshan complex have similar chondrite-normalized REE patterns. The preliminary Sr-Nd isotopic data indicate that all rocks were not obviously contaminated by the wall rock and later hydrothermal imprint. All these data have suggested that most of rocks are probably derived from a common parent magma which underwent a fractional crystallization, then the magnetite- and apatite-rich rocks were formed.However, several batches of magma are needed to form three zones.
ultramafic-alkaline intrusion magnetite-apatite Fanshan north China craton
Neng Jiang
Key Laboratory for Mineral Resource Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
国际会议
第八届国际矿床地质会议(Proceedings of the Eighth Biennial SGA Meeting)
北京
英文
98-101
2005-08-18（万方平台首次上网日期，不代表论文的发表时间）