摘要
对位于中亚造山带东南部,紧邻华北板块北缘的查干哈达花岗岩体进行了岩石地球化学研究。主量元素研究显示查干哈达花岗岩具有SiO_2含量变化较大、准铝质-弱过铝质、碱性-碱钙性、偏铁质等特征;微量元素显示其具有K,Rb,Th,U,Pb和Nd等相对富集,Sr,Ba,Ti,Nb和Ta等相对亏损,稀土总量较高且变化大(96. 7×10~(-6)~373×10~(-6),平均276×10~(-6)),具有高的La_N/Yb_N值(4. 42~33. 0),轻稀土富集,具有较强的Eu亏损(δEu=0. 28~0. 67)等特征。绝大多数样品的ACNK均<1. 1、P_2O_5含量均随着SiO_2含量的升高而降低,表明了查干哈达岩体花岗岩应属于Ⅰ型花岗岩。
Chaganhada pluton is located in the southeast of the Central Asian Orogenic Belt( CAOB) and adjacent to the north margin of the North China Craton( NCC). The SiO_2 of Chaganhada granites contents show variety,and the Chaganhada Pluton belongs to metaluminous to weakly peraluminous,alkali-calcic to alkali,ferroan granites. Chaganhada granites are all enriched in K,Rb,Th,U,Pb,Nd,LREE and depleted in Sr,Ba,Ti,Nb,Ta,HREE. All samples display high and variety total REE contents( 96. 7 × 10~(-6)~ 373 × 10~(-6),average 276× 10~(-6)),and strong negative Eu anomalies. The chondrite-normalized REE patterns of Chaganhada granite are characterized by light REE enrichments relative to heavy REE with high,high La_N/Yb_N ratios( 4. 42 ~ 33. 0)Most samples characterized as ACNK < 1. 1,and negative correlation between P_2O_5 contents and SiO_2 contents. It indicate that Chaganhada granites belong to Ⅰ-type granites.
引文
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