Petrochemistry and mineralogy of Dongyuan tungsten-bearing pluton in eastern Jiangnan Orogen
Petrochemistry and mineralogy of Dongyuan tungsten-bearing pluton in eastern Jiangnan Orogen
复制标题
DOI：
--
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Z. Ji
中科院分区：
文献类型：
--
作者：
Z. Ji
东源岩体位于安徽省南部，是江南造山带东部的一部分。由花岗闪长岩、二长花岗岩、正长花岗岩组成，长石中有明显的绢云母和碳酸盐形成，黑云母中有明显的白云母和云母形成。锆石LA-ICP-MS U-Pb定年结果表明，岩体侵位时间为146.7Ma。此外，在花岗岩中还发现了丰富的继承锆石，新元古代锆石的平均年龄为（770.2±9.7）Ma。东源岩体中的黑云母属高镁型，在物源判别图解上位于壳幔带。东源岩体属高钾钙碱性钾玄岩系列，属偏铝质过铝质，具相对高Sr、Ba，低Y、Yb，弱负Eu异常（δEu = 0.74~0.83）。富轻稀土元素（LREE）和轻离子亲石元素（LILE），亏损高场强元素（HFSE），具有强烈的稀土分异模式。该岩体具有较高的87 Sr/86 Sr初始值（0.7124）、较低的eNd（t）值（-5.53）和可变的锆石eHf（t）值（-13.0~ -7.0）。元素和同位素数据表明，东源花岗岩与埃达克岩具有一定的亲缘关系，推测其可能是增厚的下地壳部分熔融的产物，地幔成分的贡献很小。
Dongyuan pluton, geographically located in south Anhui Province, is a part of eastern Jiangnan orogen. It is composed of granodiorite, monzogranite, syenogranite, showing obvious formation of sericite and carbonate in feldspar, and formation of muscovite and chlorite in biotite. Zircon LA-ICP-MS U-Pb dating results show that the pluton was emplaced at 146.7 Ma. In addition, abundant inherited zircons are identified in the granite, showing the average age of the Neoproterozoic zircon is(770.2±9.7) Ma. Biotite in Dongyuan pluton can be classified as high-Mg type, and is plotted in the crust-mantle zone on the material source discrimination diagram. The Dongyuan pluton belongs to the high potassium calc alkaline and shoshonitic series, being metaluminousperaluminous, showing relatively high Sr and Ba, low Y and Yb, and weak negative Eu anomalies(δEu = 0.74~0.83). It is enriched in light rare earth elements(LREE) and light ion lithophile elements(LILE) but is depleted in high field strength elements(HFSE), exhibiting strongly fractionated REE pattern. The pluton exhibits high initial 87Sr/86 Sr ratios(0.7124), low eNd(t)(–5.53), and variable zircon eHf(t)(–13.0~ –7.0) values. The elemental and isotopic data suggests that the Dongyuan granite shows some affinities with adakite, so can be postulated to be most likely derived from partial melting of thickened lower crust with little contribution from mantle components.