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现代地质 ›› 2013, Vol. 27 ›› Issue (3): 509-524.

• 岩石学 • 上一篇    下一篇

福建太姥山地区和鼓山地区A型花岗岩对比及其地球动力学意义

李良林1,2,3，周汉文2，陈植华4，王锦荣5，陈正华1,3，肖依2   

  1. 1重庆地质矿产研究院 外生成矿与矿山环境重庆市重点实验室，重庆400042；
    2中国地质大学 地球科学学院，湖北 武汉430074；3煤炭资源与安全开采国家重点实验室 重庆研究中心，重庆400042；
    4中国地质大学 环境学院，湖北 武汉430074；5中国冶金地质总局 第二地质勘查院，福建 莆田351111
  • 收稿日期:2012-05-28 修回日期:2012-10-24 出版日期:2013-06-07 发布日期:2013-06-08
  • 通讯作者: 周汉文，男，教授，1964年出生，岩石学与地球化学专业，主要从事岩石地球化学研究。
  • 作者简介:李良林，硕士研究生，1986年出生，矿物学、岩石学、矿床学专业，主要从事岩石地球化学研究。 Email：lilianglin1124@163.com。
  • 基金资助:

    福建省国土资源厅项目“福建花岗岩地质地貌综合景观对比研究”(2009046095）。

Comparison of A-type Granites from Taimushan and Gushan Regions in Fujian Province and Their Geodynamic Significance

LI Liang-lin1,2,3, ZHOU Han-wen2, CHEN Zhi-hua4, WANG Jin-rong5, CHEN Zheng-hua1,3, XIAO Yi2   

  1. 1Chongqing Key Laboratory of Exogenic Mineralization and Mine Environment, Chongqing Institute of Geology and Mineral Resources, Chongqing400042, China;
    2Faculty of Earth Sciences, China University of Geosciences, Wuhan, Hubei430074, China;
    3Chongqing Research Center of State Key Laboratory of Coal Resources and Safe Mining, Chongqing400042, China;
    4School of Environment Studies, China University of Geosciences, Wuhan,Hubei430074, China;
    5No.2 Geological Prospecting Institute, China Metallurgical Geology Bureau, Putian, Fujian351111, China
  • Received:2012-05-28 Revised:2012-10-24 Online:2013-06-07 Published:2013-06-08

PDF (PC)

3649

被引次数

5

摘要：

太姥山和鼓山位于福建东南沿海地带。岩石学和岩相学研究表明太姥山地区和鼓山地区花岗岩分属铝质A型花岗岩和碱性A型花岗岩。锆石LA-ICP-MS U-Pb同位素定年结果表明，两地区花岗岩成岩年龄分别为(96.6±1.6)Ma（MSWD=0.65）和（99.4±2.3）Ma（MSWD=0.49），成岩时代均属晚白垩世早期。结合中国东部沿海两类A型花岗岩，讨论了它们在岩石学、岩相学、地球化学及其判别图解上的区别。总体上认为，碱性A型花岗岩在AKI值、TFeO/MgO比值、104×Ga/Al以及（Zr+Nb+Ce+Y）值上均大于同区域的铝质A型花岗岩，但上述化学指标的数值也存在一定范围的重叠；且传统A型花岗岩判别图解不完全适用于强分异的铝质A型花岗岩。地球化学特征表明，两地区A型花岗岩应具有相似的源区，即岩浆起源于地壳物质熔融，同时成岩过程有一定的地幔物质参与。但鼓山地区碱性A型花岗岩较太姥山地区铝质A型花岗岩有更多地幔物质的加入，导致前者显示出部分幔源岩浆起源的特征。结合地球化学、野外地质、区域背景及年代学综合判定，两地区花岗岩成因与古太平洋板块对欧亚板块的俯冲角度密切相关，均属于弧后拉伸体制之下的构造环境。

关键词: 碱性A型花岗岩, 铝质A型花岗岩, 岩石成因, 太姥山, 鼓山, 中国东部沿海

Abstract:

Taimushan and Gushan are located in the southeast coastal areas of Fujian. Petrology and petrography studies have shown that Taimushan and Gushan granites belong to aluminous A-type granitoids and alkaline A-type granitoids respectively. Zircon LA-ICP-MS U-Pb dating results indicate that the granites in two regions, whose diagenetic ages were (96.6±1.6) Ma (MSWD=0.65) and(99.4±2.3) Ma (MSWD=0.49) respectively, formed in the earlier of Late Cretaceous. Based on granites of the two regions, we focused on the difference of two types of A-type granites in the eastern coast of China in terms of the petrology, petrography, geochemistry and discrimination diagrams. On the whole,  the AKI values, TFeO/MgO ratio, 104×Ga/Al and (Zr+Nb+Ce+Y) values of the alkaline A-type granites  are higher than those of aluminous A-type granites of the same region, but also there is a range of overlap in above chemical indicators, and the traditional A-type granite discrimination diagrams are not thoroughly applicable to the strong differentiation aluminous A-type granite. Geochemistry shows that the granites in two regions should have a similar source, namely magma originated from the partial melting of crustal material and the process of diagenesis have some mantle material involved in. However, alkaline A-type granites in Gushan region may have more mantle material involved in, showing some characteristics of mantle-derived magmatic origin. Integrated with geochemistry, field geology, regional background and geochronology reveal that petrogenesis of the granites of two regions is closely related to the angle of the subduction of PaleoPacific Plate to the Eurasian Plate, and their tectonic environment belongs to a back-arc tensional tectonic environment.

Key words: alkaline A-type granite, aluminous A-type granite, petrogenesis, Taimushan, Gushan, eastern coast of China

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