| 粤北油洞岩体SHRIMP锆石U-Pb年龄、地球化学特征及其成因研究 |
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| 引用本文： | 黄国龙,曹豪杰,凌洪飞,沈渭洲,王小冬,伏顺成.粤北油洞岩体SHRIMP锆石U-Pb年龄、地球化学特征及其成因研究[J].地质学报,2012,86(4):577-586. |
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| 作者姓名： | 黄国龙 曹豪杰 凌洪飞 沈渭洲 王小冬 伏顺成 |
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| 作者单位： | 核工业二九○研究所 |
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| 基金项目： | 核工业地质局科研项目(南京大学);教育部科学研究重大项目(编号306007)资助成果 |
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| 摘 要： | 油洞岩体位于诸广南部岩体中部,是一个重要的产铀岩体,岩性为中粒小斑状二云母花岗岩。SHRIMP锆石U-Pb年龄为232±4Ma(MSWD=3.2),属于印支早期岩浆活动产物。该岩体在主量元素方面,具有富硅(SiO2平均为72.65%)、富铝(A/CNK值平均为1.12)和高的K2O/Na2O比值(平均为1.79);在微量元素方面,大离子元素富集,Ba、Sr、P、Ti、Nb、Ta亏损明显,具有高的Rb/Sr(平均为8.08)和Rb/Nb比值(平均为20.96);在稀土元素方面,轻稀土明显富集,配分模式呈右倾型,Eu亏损明显;在同位素方面,εNd(t)值低(平均为-11.9),(87Sr/86Sr)i高(平均为0.72330),Nd模式年龄古老(平均为1954 Ma)。这些特征一致表明,油洞岩体属于典型的壳源型花岗岩范畴,是在华南地块和印支地块碰撞结束后不久形成的伸展构造环境中,位于中—下地壳部位的古—中元古代地壳组分由于在地壳缩短之后的伸展、减薄环境下产生的减压、导水和地幔上涌等因素的综合影响下,由泥质岩和砂质岩混合组成的源区发生部分熔融而形成。
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| 关 键 词： | SHRIMP锆石U-Pb定年 元素和同位素地球化学 伸展构造 油洞岩体 |
| 收稿时间： | 2011/7/26 0:00:00 |
| 修稿时间： | 2011/10/20 0:00:00 |
SHRIMP U-Pb zircon age, geochemistry and genesis of Youdong granite in Northern Guangdong |
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| HUANG Guolong,CAO Haojie,LING Hongfei,SHEN Weizhou,WANG Xiaodong and FU Shuncheng.SHRIMP U-Pb zircon age, geochemistry and genesis of Youdong granite in Northern Guangdong[J].Acta Geologica Sinica,2012,86(4):577-586. |
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| Authors: | HUANG Guolong CAO Haojie LING Hongfei SHEN Weizhou WANG Xiaodong and FU Shuncheng |
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| Institution: | Research Institute No.290, CNNC |
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| Abstract: | The Youdong granite,located in the central part of the southern Zhuguang granitic complex,is important uranium-bearing granite.It consists mainly of medium-grained,small porphyritic two-mica granite.SHRIMP U-Pb dating of zircon collected from the granite yields an age of 232±4 Ma(MSWD=3.2),indicating it was the product of granitic magmatic activity in the early Indosinian epoch.The granite is rich in Si(average SiO2 of 72.65%) and Al(average A/CNK value of 1.12),with a high ratio of K2O/Na2O(average 1.79).It is also enriched in large ion elements including light rare earth elements,but significantly depleted in Sr,Ba P,Ti,Nb and Ta,with high ratios of Rb/Sr(average 8.08) and Rb/Nb(average 20.96).The rare earth element distribution patterns show right-inclining type with significant Eu depletion.The Youdong has high(87Sr/86Sr)i ratios(average 0.72330) and low εNd(t) values(average-11.9) with old Nd model ages(average 1954 Ma).These features consistently indicate that the Youdong complex is a typical crustal rock-sourced granite formed in an extensional tectonic environment that began shortly after the end of collision between the South China block and Indosinian block.Under such tectonic settings,the Youdong granite was formed by partial melting of Paleoproterozoic-Mesoproterozoic argillaceous and arenaceous rocks in the intermediate-lower crust sources under the influence of lithosphere thinning and asthenosphere ascending. |
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| Keywords: | SHRIMP zircon U-Pb dating element and isotope geochemistry extensional environment Youdong granite body |
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