| The Hongge layered intrusion is located in the Emeishan Large Igneous Province(ELIP), SW China. It is the biggest l mafic–ultramafic intrusions that host giantFe–Ti–V oxide ore deposits (50billion tons according to the newest data) It is a typicaltype of “Panzhihua-style” Iron ore deposit.The deposit is related to mafic–ultramafic intrusions closely, of which its ore bodypre-dates in the ore-bearing rock body. The ore-bearing rock mainly distributed fromnorth to south, along with the ore-bearing rock there are a huge amount ofpermo-emeishan basalt, and they are homeosis during the Magma evolution.This paper reached several conclusions according to the analysis of the structurefeature and ore-body of ore structure, the chemical-feature of rock ore. And conclusionswill be listed below:(1) The outlook of The mafic–ultramafic intrusions in hongge area are basin-shaped,all of the basin-shaped rocks together dominated the distribution of mafic–ultramaficintrusions. In hongge, rocks are mainly consisted of amphibole olivine, pyroxenolite,Gabbro(disseminated iron ore), banded iron ore, syenite and several other kinds ofrocks. In Baicao ore block, we even noticed the existence of Magmatic sulfide orebodies(Massive sulfide nickel and cobalt ore body).(2) If different types of rocks are interconnecting, then they are abrupt contact (dueto pulsation intrusion contact). By observations made in filed trip, the magmaticeruption or emplacement order happened in hongge area is as follow:microlitic gabbro, gabbroporphyrite, Basalt'gabbro, disseminated ironore'pyroxene peridotite, gabbro, block iron ore'syenite(Dike)'Diabase dykes,gabbroporphyrite dyke'Granite.(3) Pyrrhotite, a small amount of augite, sahlite, Bronzite, hornblende, Phlogopite,magnetite, ILMENITE, andesine and several other kinds of rocks consist Massivesulfide nickel and cobalt ore. In which mineral components Compared with iron ore arerelatively different,: magnetite is lack of Ti、Al、V、Mg, while abundant in Fe; ilmeniteis lack of Ti、Mg while abundant in Fe; sahlite, is lack ofTi、Al、V、Mg, while abundantin Si、Mn; augite is lack of Ca, while abundant in K、Na、Ni; hornblende is lake of Ti、V、Mg, while abundant in Fe; all of the above suggest that massivesulfide form insurroundings abundant in Fe and Ni and while lack of the existence of Ti、V、Mg.(4) The feature of microelement and rare earth element in hongge area share a lotin common, which reflects the feature of Cognate magma evolution series products.Yet the difference are reflected in the component difference in Ti、K，P,and Rb、Ba、Th、REE. Rocks that is abundant in Fe have higher Ti, and lower K, besides, Rb、Ba、Zr and.LREE(La、Ce、Pr、Nd) are also low. (5)Iron ore in hongge area exits in two forms, one of which is abundant inhigh-content Co(massive ore,of which the content of Co is more than0.01%),it couldbe the result of deep late iron rich fluid emplacement; the other form is lean ironore(disseminated ore,,of which the content of Co is less than0.01%), The iron contentis generally less than20%,for instance, the educt of Small particles magnetite which arecommon to see in ferro–basalt, iron gabbro and Pyroxenite lean ore.(6) PGE elements in hongge area shows obvious segregation, the elements becomemore abundant in iron ore and massive sulfide while become less abundant in basalt andpyroxene peridotite, which suggest that sulfide and iron can be both abundantin igneous rocks. From north to south, from Ma’anshan mining area to hongge miningarea, the PGE content in culsonite-titanomagnetite ore is decreasing. PGE content ofbasalt from borehole ZK2908whos that, the content of PGE is deceasing gradually. |
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