摘要
为了解库鲁克塔格地区的地壳生长过程,对该区419.2~399.9 Ma的4个花岗质岩体进行了全岩Sr-Nd同位素研究,并选择其中两个岩体进行锆石Hf同位素分析。结果表明,4个岩体的岩石均具有中等Sr初始值(0.70658~0.71206),εNd(t)为-11.82^-6.81,高于同造山(同增生)的花岗质岩石,εHf(t)值为-6.59~0.82,tDM为1.35~1.80 Ga。结合岩石地球化学特征认为,该期的地壳生长方式可能是在活动大陆边缘环境下,由强烈的俯冲作用导致了壳幔物质在源区混合形成原始岩浆,随后这一壳幔混源岩浆经过结晶分异并上升侵位固结成岩,从而造成陆壳垂向生长,该生长方式也为塔里木北缘古生代中期俯冲消减的构造环境(安第斯型活动大陆边缘)提供了证据。
Middle-Paleozoic granitic rocks in Kuruktag is of great significance to understand the process of crustal growth. In this paper,Sr-Nd isotopic data for four granitic intrusions (399.9~419.2Ma)and Hf isotopic data for two of them were researched.These rocks have medium initial 87Sr/86Sr ratios (0.70658-0.71206),and negative εNd(t)values (-- 11.82^-6.81),which are higher than that of synorogenic granitic rocks,two intrusions have variable εHf(t)values from -6.59 to 0.82,yielding tDM of 1.35to1.80Ga.In combination with geochemical characteristics,it is believed that the crustal growth of this period may be in the active continental margin environment,and parental magma was produced by mixing of crust and mantle materials in the source region.The magma have experienced fractional crystallization during em- placement,resulting in vertical growth of continental crust.This continental growth process also provides evidence for the Andean-type active continental margin of the northern margin of the Tarim Craton in the mid Paleozoic.
作者
邹明煜
郭瑞清
梁文博
胡雪原
吴华楠
张梦迪
Z0U Ming-yu;GU0 Rui-qing;LIANG Wen-bo;HU Xue-yuan;WU Hua-nan;ZHANG Meng-di(Geological and Mining Engineering Institute,Xinfiang University,Urumqi 830047,China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2018年第6期1074-1083,共10页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
中国地质科学院地质研究所联合基金项目(U1403291)
