摘要
菁布拉克基性-超基性岩带位于西南天山那拉提深大断裂附近,出露有菁布拉克、喀拉达拉、恰干萨依、乔勒铁克西、丘拉克特勒克、苏鲁、琼阿乌孜等基性超基性岩体.对这些岩体稀土元素分析结果显示:该区岩体稀土含量低,轻稀土略微富集;δEu正、负异常均有体现;Ce/Ce*则均为负异常.结合岩石化学数据和同位素数据,认为该区岩体是亏损地幔部分熔融产生的,熔融所产生的基性-超基性岩浆在上侵过程中经历了流体交代作用和地壳不同程度的混染作用.文中还通过比较新疆北部不同含矿性岩体的稀土元素特征,初步探讨了该区岩体Cu、Ni矿的成矿属性.
The basic-ultrabasic rocks of Jingbulake belt are situated within the Nalati fault in southwestern Tianshan, where more than ten intrusions： Jingbulake, Kaladala, Qiagansayi, Qiaoletiekexi, Qiulaketeleke, Sulu, Qiongawuzi, etc., were discovered. Based on the analysis of rare earth elements （REE）, the ΣREE is12. 19 to 175.02 × 10^-6, with an average of 48. 88 × 10^-6; the values of ELREE/ EHREE are from 0. 77 to 1.89, averaging 1.36, which shows that EREE are low and that LREE is slightly enriched; the values of 8Eu show both positive and negative anomalies and all Ce/Ce^＊ are negative anomalies. Combined with the data of major and isotope elements, these features suggest that the magma was derived from the depleted asthenospheric mantle. In the process of upward emplacing, the magma produced by partial melting undergone fluid metasomatization, and was contaminated by crustal materials to varying degrees. Meanwhile, through comparing to the features of REE in different bodies in Northern Xinjiang, the copper-nickel ore potential of these intrusions are discussed.
基金
国家重点基础研究发展(973)计划(2001CB409806)资助
