辽宁营口后仙峪硼矿区超镁橄榄岩的控矿作用

为了研究辽宁营口后仙峪硼矿区超镁橄榄岩与硼矿的关系,作者通过硼矿与超镁橄榄岩两者在产出空间关系、岩石学和地球化学方面的比较,发现:①硼矿体与超镁橄榄岩空间关系上具一致性;②硼矿体与超镁橄榄岩在岩石学上具继承性;③硼矿石、超镁橄榄岩的地球化学特征具相似性,从而得出超镁橄榄岩不仅是该区硼矿的容矿岩石,而且对硼矿的形成有决定性的岩控作用,进一步认为辽东硼矿的容矿岩石不全是镁质大理岩,其他富镁岩石在一定条件下也可成为硼矿的容矿岩石。

Ore-control role of ultra-magnesium peridotite in Houxianyu boron ore district, Yingkou, Liaoning Province

Located in Yingkou of Liaoning Province, the Houxianyu boron deposit is of the suanite-szaibelyite type, with the host rock being the serpentinized and magnesitized ultra-magnesium peridotite. A comparison of spatial relationship, petrology and geochemistry between the boron deposit and the ultra-magnesium peridotite has led to the following conclusions:(1) the ore bodies have the same spatial relationship with the ultra-magnesium peridotite, because the boron bodies are hosted in the ultra -magnisium peridotite and magnesite marble in lamellar, lamellated and lentoid forms;(2) the ores show inheritance relationship with the ultra-magnesium peridotite in mineral formation, texture and structure. The metasomatic relict texture and the metasomatic pseudomorphic texture find expression in the metasomatic relationship of szaibelyite with forsterite, serpenite and early ore minerals. The relict structure is obvious, and such structures as the blasto-nodule structure,the blasto-ball structure,the jet brecciated structure, the blasto-banded structure, the brecciated structure, the anti-brecciated structure,the granophyric structure, and the tripod structure all have to do with the ultra-magnisium peridotite and serpenitinized peridotite;(3) the ores show inheritance in geochemistry, especially in REE. The boron ores and the ultra-magnisium peridotite both show magnesium-rich, iron-rich and boron-rich characteristics, and also show close relationship in the evolution of rock formation. They are similar in trace elements. They have the same kinds and contents of trace elements, and their features of evolution are similar. They are consistent in REE evolution, and both have the "V" type REE pattern. It is thus held that the ultra-magnisium peridotite not only is one kind of host rocks, but also controls the characteristics of the boron ores in the boron deposit. In addition, magnesium marble is not the only host rock in eastern Liaoning-southern Jilin boron deposits- and other magnesium-rich rocks can also serve as the host rocks of boron deposits under certain conditions.