中国地质
中國地質
중국지질
CHINESE GEOLOGY
2010年
2期
324-333
,共10页
斜长角闪岩%原岩恢复%地球化学%弓长岭
斜長角閃巖%原巖恢複%地毬化學%弓長嶺
사장각섬암%원암회복%지구화학%궁장령
amphibolites%original rock%geochemistry%Gongchangling
弓长岭二矿区既是大型条带状铁矿床,同时又是大型磁铁富矿床,自1949年建矿以来,一直是鞍钢的主体矿山和高品位富矿的主要供应地.笔者在总结矿床地质特征的基础上,对矿区的主要变质岩-斜长角闪岩类的主量元素、微量元素和稀土元素进行了分析.结果显示:主量元素的平均化学成分与基性火山岩中玄武岩成分相似,MgO和CaO含量比较高,而且Na_2O>K_2O;微量元素:相容元素Sc、V、Cr、Co、Ni、Cu的含量比较高,属于右倾型;(Rb/Yb)_N值为5.95～132.93,平均值为49.34,远远大于1,为强不相容元素富集型;大离子亲石元素Rb、Ba、K、Sr明显富集,但Th、U强亏损;高场强元素中Zr、Hf明显富集.而Nb、P为中等亏损,Ti为弱亏损,与亏损型洋中脊拉斑玄武岩很相近;稀土元素具有∑REE低(21.09×10~(-6)～69.13×10~(-6)平均40.44×10~(-6))、LREE略有富集(LREE/HREE=1.70～2.58,平均2.27;(La/Yb)_N:0.93～4.27,平均值1.60)的稍右倾型或平坦型特征.轻稀土分馏不明显(La/Sm)_N: 0.87～3.28,平均值1.42).根据主量、微量和稀土元素的特征,并结合环境构造判别图解,笔者认为,研究区斜长角闪岩的原岩为大洋中脊拉斑玄武岩.
弓長嶺二礦區既是大型條帶狀鐵礦床,同時又是大型磁鐵富礦床,自1949年建礦以來,一直是鞍鋼的主體礦山和高品位富礦的主要供應地.筆者在總結礦床地質特徵的基礎上,對礦區的主要變質巖-斜長角閃巖類的主量元素、微量元素和稀土元素進行瞭分析.結果顯示:主量元素的平均化學成分與基性火山巖中玄武巖成分相似,MgO和CaO含量比較高,而且Na_2O>K_2O;微量元素:相容元素Sc、V、Cr、Co、Ni、Cu的含量比較高,屬于右傾型;(Rb/Yb)_N值為5.95～132.93,平均值為49.34,遠遠大于1,為彊不相容元素富集型;大離子親石元素Rb、Ba、K、Sr明顯富集,但Th、U彊虧損;高場彊元素中Zr、Hf明顯富集.而Nb、P為中等虧損,Ti為弱虧損,與虧損型洋中脊拉斑玄武巖很相近;稀土元素具有∑REE低(21.09×10~(-6)～69.13×10~(-6)平均40.44×10~(-6))、LREE略有富集(LREE/HREE=1.70～2.58,平均2.27;(La/Yb)_N:0.93～4.27,平均值1.60)的稍右傾型或平坦型特徵.輕稀土分餾不明顯(La/Sm)_N: 0.87～3.28,平均值1.42).根據主量、微量和稀土元素的特徵,併結閤環境構造判彆圖解,筆者認為,研究區斜長角閃巖的原巖為大洋中脊拉斑玄武巖.
궁장령이광구기시대형조대상철광상,동시우시대형자철부광상,자1949년건광이래,일직시안강적주체광산화고품위부광적주요공응지.필자재총결광상지질특정적기출상,대광구적주요변질암-사장각섬암류적주량원소、미량원소화희토원소진행료분석.결과현시:주량원소적평균화학성분여기성화산암중현무암성분상사,MgO화CaO함량비교고,이차Na_2O>K_2O;미량원소:상용원소Sc、V、Cr、Co、Ni、Cu적함량비교고,속우우경형;(Rb/Yb)_N치위5.95～132.93,평균치위49.34,원원대우1,위강불상용원소부집형;대리자친석원소Rb、Ba、K、Sr명현부집,단Th、U강우손;고장강원소중Zr、Hf명현부집.이Nb、P위중등우손,Ti위약우손,여우손형양중척랍반현무암흔상근;희토원소구유∑REE저(21.09×10~(-6)～69.13×10~(-6)평균40.44×10~(-6))、LREE략유부집(LREE/HREE=1.70～2.58,평균2.27;(La/Yb)_N:0.93～4.27,평균치1.60)적초우경형혹평탄형특정.경희토분류불명현(La/Sm)_N: 0.87～3.28,평균치1.42).근거주량、미량화희토원소적특정,병결합배경구조판별도해,필자인위,연구구사장각섬암적원암위대양중척랍반현무암.
Iron resources in the second ore district of Gongchangling is not only a large-sized banded low grade iron ore deposit but also a large-sized high grade iron ore deposit. Since 1949, it has become the main mine providing high grade iron for the Anshan Steel Iron Group Cooperation. The authors studied the second ore district of Gongchangling, and analyzed major elements, trace elements, rare earth elements of the amphibolites. Some conclusions have been reached: ① the average compositions of major elements are SiO_2 49.89%, TiO_2 0.86%,Al_2O_3 14.85%, Fe_2O_3 3.47%, FeO 7.88% ,MnO 0.24%, MgO 7.94%, CaO 8.65%, Na_2O 2.79%, K_2O 1.17%,and P_2O_5 0.07%, similar to things of basalt: MgO and CaO are high, Na_2O>K_2O; ②as for trace elements, the content of compatible elements (Sc, V, Cr, Co, Ni, Cu) is high, (Rb/Yb)_N=5.95～132.93, with an average of 49.34; Rb, Ba, K, Sr, Zr, Hf are enriched, whereas Th, U, P, Nb, Ti are depleted, similar to things of deficiency type mid-ocean ridge tholeiite; ③REE:∑REE ratios are relatively low (21.09×10~(-6)～69.13×10~(-6), averagely 40.44×10~(-6)), LREE/HREE=1.70~2.58, (2.27 on average); (La/Yb)_N=0.93～4.27 (1.60 on average), and (La/Sm)_N=0.87～ 3.28 (1.42 on average); ④the original rock of amphibolites is basalt and, according to the discrimination diagram of environment structure, the original rock of amphibolites should be mid-ocean ridge tholeiite.
