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| 华南印支期花岗岩类的岩石特征、成因类型及其构造动力学背景探讨 | |
| 引用本文： | 郭春丽,郑佳浩,楼法生,曾载淋.华南印支期花岗岩类的岩石特征、成因类型及其构造动力学背景探讨[J].大地构造与成矿学,2012,36(3):457-472. |
| 作者姓名： | 郭春丽 郑佳浩 楼法生 曾载淋 |
| 作者单位： | 1. 中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点实验室,北京100037 2. 中国地质大学地球科学与资源学院,北京,100083 3. 江西省地质调查研究院,江西南昌,330030 4. 江西省赣南地质调查大队,江西赣州,341000 |
| 基金项目： | 国家重点基础研究发展计划(973项目)，国土资源大调查工作项目，国土资源部公益性行业科研专项经费项目 |
| 摘 要： | 华南地区印支期花岗岩按照成因类型可分两类,第一类属强过铝质S型花岗岩,富含过铝质矿物,富SiO2、Al2O3和P2O5,高A/CNK值,微量元素原始地幔标准化分布型式图中富集Rb、U、Ta、Zr、Hf,亏损Ba、Sr、Nb、Ti;稀土元素球粒陨石标准化分布型式图中具显著的负Eu异常,稀土元素总量偏低(ΣREE<80×10-6);第二类属准铝质I型花岗岩,含角闪石等镁铁质矿物,富SiO2、Na2O。总体来说,这两类花岗岩具有高的(87Sr/86Sr)i值(0.710490～0.742118)和低εNd(t)值(-14.42～-4.1),Nd模式年龄(2.09～1.63Ga)指示印支期花岗岩为典型的壳源型花岗岩。CaO/(MgO+FeOT)-Al2O3/(MgO+FeOT)(摩尔比)图解表明这些花岗岩主要来源于变质杂砂岩和变质泥岩的部分熔融,夹杂了少量变质玄武岩和变质英云闪长岩。华南印支期花岗岩形成于挤压加厚的地壳发生局部伸展-减薄时期,推断印支期发生了多期次的岩石圈挤压和拉张,花岗岩侵位于大规模岩石圈挤压后局部减压-伸展的构造环境中。 |
| 关 键 词： | 岩石地球化学 Sr-Nd同位素 花岗岩成因类型 印支期 华南 |
Petrography, Genetic Types and Geological Dynamical Settings of the Indosinian Granitoids in South China |
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| GUO Chunli , ZHENG Jiahao , LOU Fasheng , ZENG Zailin.Petrography, Genetic Types and Geological Dynamical Settings of the Indosinian Granitoids in South China[J].Geotectonica et Metallogenia,2012,36(3):457-472. | |
| Authors: | GUO Chunli ZHENG Jiahao LOU Fasheng ZENG Zailin |
| Institution: | 1.MLR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;2.School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;3.Jiangxi Provincial Institute of Geological Survey,Nanchang 330030,Jiangxi,China;4.Gannan Geological Survey Party of Jiangxi Province,Ganzhou 341000,Jiangxi,China) |
| Abstract: | The Indosinian granitoids in South China can be divided into two genetic types.One category is strongly peraluminous S-type granites,which is rich in peraluminous minerals,high SiO2,Al2O3 and P2O5 contens,A/CNK values and enriched in Rb,U,Ta,Zr,Hf,obviously depleted in Ba,Sr,Nb and Ti in the primitive mantle-normalized trace element spider diagrams.The rocks are characterized by low REE contents(ΣREE<80×10-6) showing right dipping REE patterns with significant negative Eu anomalies in the chondrite-normalized REE patterns.The other category is metaluminous I-type granites bearing hornblende and other mafic minerals such as biotite,rich in SiO2,Na2O.In general,these two types of granites all show high(87Sr/86Sr)i values(0.710490~0.742118) and low εNd(t) values(-14.42~-4.1).Nd model ages(2.09~1.63 Ga) of the granitic rocks indicate that the Indosinian granites are typically crust-derived.Molar CaO/(MgO+FeO)-molar Al2O2/(MgO+FeOT) diagram shows that these granites are mainly derived from partial melting of metamorphic sandstone and metamorphic mudstone mixed with a small amount of metamorphic basalt and metamorphic tonalite rocks.Indosinian granitoids were formed in interval extensional process of collision stage of early Mesozoic in South China.It could be inferred that Indosinian granites were emplaced in extensional tectonic environment after large-scale lithospheric decompression. |
| Keywords: | geochemistry Sr-Nd isotopes genetic type of granites Indosinian South China |
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