【作者】 刘敬青；

【导师】 肖荣阁；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2007， 硕士

【摘要】 辽东硼矿是我国特有的变质热液交代型硼矿,它发育在我国古元古代的“辽吉古裂谷”中,含矿岩系为经过角闪岩相区域变质作用一套变质岩组合,产于宽甸群的刘家河组、高小岭组、林家台组、老营沟组和砖庙组。含矿岩系主要分布在辽东半岛南、东部地区,西自营口,东至宽甸。主要含矿岩系包括:大石桥后仙峪含硼岩系、翁泉沟含硼岩系、杨木杆含硼岩系、砖庙含硼岩系。变质岩石类型有电气石变粒岩、黑云变粒岩、浅粒岩、斜长角闪岩、混合岩和碳酸盐岩。电气石变粒岩、黑云变粒岩、浅粒岩在区域上呈层状产出,层理清晰,延伸稳定,它们之间常有过渡关系。他们多为条带状、块状构造。电气石变粒岩原岩主要为泥岩、粘土岩、和砂岩,部分正变质岩原岩为中-酸性凝灰岩;黑云变粒岩、浅粒岩从主量元素、微量元素特征看,原岩表现出正变质的特点,但是从稀土元素看,黑云变粒岩、浅粒岩与电气石变粒岩之间关系密切,其稀土配分模式与大陆壳和次大陆壳地槽的粘土和粘土页岩稀土配分型式非常相似。辽东含矿岩系的变、浅粒岩原岩为一套泥质岩、粉砂岩和少量的火山碎屑岩。斜长角闪岩呈层状,透镜状;片麻状构造,细粒花岗变晶结构,斜长角闪岩的主量元素、微量元素、稀土元素都显示出其原岩为一套基性火山岩,具有大陆玄武岩的特点。混合岩为层状,其围岩为各种变粒岩和浅粒岩。它与围岩接触界线清楚,呈整合接触,在岩性上有过渡现象。在过渡层中有交错层理,岩层中常有残留的或呈夹层的斜长角闪岩。并常见有变、浅粒岩的残留体。花岗变晶结构,条带状、条痕状构造。地球化学方面,主量元素部分表现出岩浆成因特点,但其微量元素与变、浅粒岩相似,稀土配分模式也与变、浅粒岩相似。认为辽东含矿岩系混合岩为变、浅粒岩、斜长角闪岩经过选择重熔、混合交代形成的。碳酸盐岩一般呈似层状-透镜状,蛇纹石化强烈。在主量元素方面,与典型碳酸岩和碳酸盐岩相比,碳酸盐岩具有高镁、低钙的特点,其中TiO₂、Al₂O₃、MnO、K₂O、Na₂O、P₂O₅含量与沉积碳酸盐岩的含量相近;微量元素方面Sr、Ti亏损,特别是Ti亏损明显,反映了岩石可能是地壳成因;稀土元素方面宽甸地区的碳酸盐岩的稀土含量与中国西藏的前寒武纪碳酸盐岩和白垩纪碳酸盐岩的稀土含量非常相似,而与碳酸岩的稀土含量相差较大。反映了辽东含矿岩系的沉积成因。更多还原

【Abstract】 East Liaoning borate deposits are special matamophic-hydrothermal-metasomatic borate deposits and distributed in“Liaoji paleorift”of Paleoproterozoic of China. Their ore-bearing series are a set of metamorphic assemblages having undergone regional metamorphism of amphibolite facies, occurring in the Liujiahe、Gaoxiaoling、Linjiatai, Laoyinggou and Zhuanmiao formations, and mainly distributed in southern and eastern East Liaoning Peninsula, from Yingkou City in the west to Kuandian in the south. The main ore-bearing series include the Houxianyu,Wengquangou,Ymugan,Zhuanmiao rock series. Their metamorphic rocks are tourmaline leptynites, biotite leptynites and leptites, amphibolite rocks, migmatite and Magnesium marbles. The tourmaline leptynites, biotite leptynites and leptites occurrring distinctly stratiform continuously extend in the region, and are commonly characterized with mutual transitional relationships and with banded and massive structures.The Protolithes of tourmaline leptynites are mainly mudstone, claystone and sandstone; and, some protolithes of positive metamorphic rocks are intermediate- acid tuff. According to the major elements and trace elements, the biotite granulite and granulite show characteristics of positive metamorphic rocks; but as to REE, biotite leptynites, leptites and tourmaline are closely associated mutually, and their REE distribution patterns are fairly similar to those of the clay and clay shale distributed in the continental crust and subcontinent crust geosyncline. The evidence from petrology and geochemistry indicates that protolithes of the leptynites and leptites are equivalent to a set of argillaceous rocks, siltstones and a minor amount of pyroclastic rocks. The amphibolites are stratiform or lentoid structures with gneissic texture and fine-grained granoblastic texture; the major elements, trace elements and REE of the plagioclase amphibolites all indicate that the protolithes of amphibolites are a set of basic igneous rocks with characteristics of continental basalt.The stratiform migmatites are surrended by their country rocks composed of a variety of leptynites and leptites. The migmatites are conformable contact with their country rocks with distint boundaries. There are cross-beddings in the transitional layers and some interbedded amphibolites still remain in the strata so that the relics of leptynites and leptites are commonly discovered. The characteristic of major elements are similar to igneous, but the trace and REEelements are similar to the leptynites and leptites. According to the characteristics, the migmatites were formed by the selected remelting or mix replacement of amphibolites, leptynites and leptites.The stratiform and lenticular Magnesium marbles with intense serpentinization can be traced across the area with discontinuation. Compare to the sedimentary and igneous carbonates , they are higher Mg and lower Ca compare, and the content of TiO2, Al2O3, MnO, K2O, Na2O, P2O5 are similar to carbonates sedimentary in the major elements, and as to trace elements, they are decrement Sr and Ti, especially Ti, which suggests that the carbonates are of originated from crust. Compare to carbonates of sedimentary of Cretaceous and Precambrian in Tibet onion of China, the REE elements are similar, but to the carbonate of igneous, they are different. So, the magnesium marbles of the ore-bearing series are of sedimentary origin.更多还原