Research Of Huyanshan Alkaline Complex Charicteristic Of Petrology And Geochemistry In Shanxi Province

The Hanshan alkaline complex outcrops in the middle part on the eastern wing of the Lüliang Mountain, Shanxi Province. Due to its typical alkaline rocktype, the Huyanshan complex has been attracted much attention from geological field. In this paper, based on field geological work, the author has detailedly and systematically studied the field geological and mineral characteristic and combinded with the analysis of microelement and lanthanon and isotope and discussed the scientific problems such as sources, mechanisms of genesis, deep dynamic processes and tectonic- magmatism evolutions. It is very significant to explore the destruction of the central and western North China Craton.The Huyanshan alkaline complex belongs to intermediate-basic rocks, deep-sourced and hypabyssal alkaline complex rocks. It was formed through muti-petrogenesis stages and epochs, and included incursionand facies. It is potassic alkaline, attributed to the alkaline-parlkaline series by alkali ratio. The rock assemblage of ring complex is consists of equal granularity monzonite -quartz monzonite-quartz syenite- aegirine augite monzonite- syenite series. The alkaline complex was formed between 155～102Ma b.p.,corresponding to the late Jurassic to early cretaceous of late Mesozoic on geological era. It is outgrowth of the Yanshan movement.The Huyanshan alkaline complex belongs to monzonite-syenite series.Its mineral includes potassium feldspar anorthose augite and less hornblende and quartz. The evolution tendency is that potassium feldspar become from many to few, (—)2V from big to small, anorthose from many to few, quartz from few to many to few and last disappear.The hornblende is less than 3%.The tendency incarnate from monzonite to syenite. The Huyanshan alkaline complex mineral formation and evolution embody from eary to late no reverse tendency.The Huyanshan alkaline complex has the chemical characteristics of SiO2-low alkali-rich, K2O-rich, Fe-rich, Mg-lean, and CaO-medium, Al₂O₃-medium. Their chondrite normalized REE patterns are characterized by high content of rare earth elements, no negative Eu anomalies and rich in LREE. In the primitive mantle-normalized trace element spider diagram, they are enriched in large ion lithophile elements (LILE) such as Cs, Rb, Ba and Th, and depleted in high field strength elements (HFSE) such as Nb, Ta and Ti. All above show that the complex was derived from enriched mantle in inner continent and the magma formation was mainly controlled by partial melting process.Different types rocks was formed in different intusive phase because mantle rock has different extent in melting process.The Huyanshan alkaline complex tectonic-magmatism might be caused not only by recorded far-field effects produced by different inter-plate convergences, but also by reflected changes in deep-seated thermal tectonic regimes. The explore evolution model of the Huyanshan complex has close connection with its geotectonic setting.The study to Huyanshan alkaline complex can reveal the formation of Hua Bei mantle rock,what's important,it extends more significant message and methord to the dynamic mechanism of the destruction of the central and western North China Craton.