Zircon U-Pb Ages, Geochemical Characteristics and Geological Significance of Jinjiling Pluton in Nanling

被引：0
|
作者：
Li J. [1 ,2 ,3 ]
Fu J. [1 ]
Ma C. [2 ]
Lu Y. [1 ]
Cheng S. [1 ]
Ma L. [1 ,2 ,3 ]
Qin Z. [1 ]
Sheng H. [3 ]
机构：
[1] Wuhan Center of China Geological Survey, Wuhan
[2] School of Earth Sciences, China University of Geosciences, Wuhan
[3] School of Geography, Liaoning Normal University, Dalian
来源：
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | 2021年 / 46卷 / 04期
关键词：
A-type granite; Isotope geochemistry; Jinjiling; Nanling; Tectonics; Zircon U-Pb dating;
D O I：
10.3799/dqkx.2020.170
中图分类号：
学科分类号：
摘要：
A study of LA-ICP-MS zircon U-Pb dating for Jinjiling pluton from Jiuyishan area in Nanling granite belt was carried out. The results show that the diagenetic age of the main medium grained porphyritic syenite and the complement fine-grained porphyritic monzonite are 156.40±0.66 Ma and 153.00±2.20 Ma, respectively. Combined with the existing data, their ages are restricted between (156.40±0.66)-(159.00±0.45) Ma and (146.00±0.86)-(153.00±2.20) Ma, which indicates that the Jinjiling pluton was formed during the early Yanshanian. Geochemical data show that the Jinjiling pluton is characterized by enriched silicone-alkali, depleted calcium-magnesium and metal uminous-peraluminous (A/KNC= 0.97-1.14). The content of rare earth elements of the main granite are significantly higher than those of the complement granites, which is 488.63×10-6-571.67×10-6 and 166.33×10-6-275.51×10-6, respectively. The main granite is enriched in light rare earth elements (LREE), with the complement granite having no obvious fractionation, both of which show negative Eu anomalies and (La/Yb)N values ranging from 10.27 to 15.84 and 0.38 to 1.13, respectively. The differentiation index (DI) are 88.76-89.20, 90.66-94.06, which indicate that the complement granite has undergone stronger magmatic differentiation. The Jinjiling pluton is enriched in large ion lithophile elements (LILE, e.g., Rb, K, Th, U, Nd and Hf) and relatively depleted in high field strength elements (HFSEs, e.g., Ba, Sr, P, Nb and Ti ), with Ga/Al(104) ratios of 3.32-5.02 (average 3.50), Zr+Nb+Ce+Y of 255.5×10-6-554.9×10-6 (average 422.37×10-6) and zircon saturation temperatures TZr of 780.31-820.67 ℃ (average 803.77 ℃), similar to geochemical features of A-type granites. The Jinjiling pluton has higher initial Sr isotope values of 0.712 58 to 0.732 51, lower εNd(t) values of -6.2 to -7.0 and εHf(t) values of -4.2 to -5.5, revealing that the source area of the Jinjiling pluton is mainly composed of crustal materials, without any contributions from mantle or new continental crust materials. The model ages of Nd and Hf are relatively close, with 1 465-1 566 Ma and 1 459-1 541 Ma, respectively, suggesting that the source rocks were separated from the mantle reservoir during the Mesoproterozoic. Combined with the geological evolution of Nanling area, it is inferred that the tectonic background of Jinjiling pluton is an intracontinental extensional environment caused by subduction of Pacific plate. © 2021, Editorial Department of Earth Science. All right reserved.
引用
收藏
页码：1231 / 1247
页数：16
相关论文
共 54 条
  • [1] Anderson J.L., Morrison J., The Role of Anorogenic Granites in the Proterozoic Crustal Development of North America, Proterozoic Crustal Evolution, pp. 263-299, (1992)
  • [2] Chen J.F., Cuo X.S., Tang J.F., Et al., Nd Isotopic Model Ages: Implications of the Grouth of the Continental Crust of Southeastern China, Journal of Nanjing University (Natural Sciences), 35, 6, pp. 649-658, (1999)
  • [3] Chen P.R., Hua R.M., Zhang B.T., Et al., Early Yanshanian Post-Orogenic Granitoids in the Nanling Region: Petrological Constraints and Geodynamic Setting, Science in China (Ser. D), 32, 4, pp. 279-298, (2002)
  • [4] Chen J.F., Jahn B.M., Crustal Evolution of Southeastern China: Nd and Sr Isotopic Evidence, Tectonophysics, 284, 1, pp. 101-133, (1998)
  • [5] Chen T.Y., Wang X.Y., Ren J.S., Et al., Iostopic Geochronology of the Jiuyishan and Baimashan Composite Cranitic Intrusions, Hunan, Geological Review, 32, 5, pp. 433-439, (1986)
  • [6] Cheng S.B., Fu J.M., Cui S., Et al., Zircon U-Pb Chronology, Geochemistry of the Indonesian Granitic Rocks from Northern Yuechengling Batholith in Guangxi-Hunan Junction, Earth Science, 43, 7, pp. 2330-2349, (2018)
  • [7] Cheng S.B., Fu J.M., Xu D.M., Et al., Geochemical Characteristics and Petrogenensis of Xuehuading Granitic Batholith and Its Enclaves, South China, Geotectonica et Metallogenia, 33, 4, pp. 588-597, (2009)
  • [8] Clemens J.D., Holloway J.R., White A.J.R., Origin of an A-Type Granite: Experimental Constraints, American Mineralogist, 71, 3, pp. 317-324, (1986)
  • [9] Diwu C.R., Sun Y., Yuan H.L., Et al., Geochronology and Hf Isotopes of Detrital Zircons from Songshan Quartzite of Dengfeng in Henan Province end Its Geological Significance, Chinese Science Bulletin, 53, 16, pp. 1923-1934, (2008)
  • [10] Du R.J., Lai J.Q., Ou Q., Et al., Petrogenesis of the Jinjiling Diabasic Dikes in Southern Hunan and Its Dynamic Significance, Acta Geologica Sinica, 93, 8, pp. 1998-2019, (2019)
123456