| 青海治多地仁地区过铝质花岗岩地球化学特征及构造意义 |
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| 引用本文：赵呈祥,李善平,潘彤,林浩,金婷婷.2018.青海治多地仁地区过铝质花岗岩地球化学特征及构造意义[J].地球学报,39(1):45-52. |
| DOI：10.3975/cagsb.2017.122901 |
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| 基金项目:青海省科技计划项目(编号: 2016-ZJ-716; 2016-SF-A3; 2016-ZJ-719) |
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| 中文摘要:治多地仁地区花岗岩侵位于松潘—甘孜地块南部, 该区花岗岩可划分为3个单元: 地仁石英闪长岩(T3δο)、日勤花岗闪长岩(T3γδ)、角考斑状二长花岗岩(T3πηγ), 岩体呈小岩基、岩株产出。花岗岩属强过铝质, 兼具I型和S型花岗岩的特点; Eu负异常明显, 轻重稀土分馏明显; Ta、Nb、Ce、Sm、Hf轻度富集, Y、Yb强烈亏损, Rb/Ba平均为0.38, Nb/Ta平均为16.44, 具下地壳源岩部分熔融花岗岩的特性; 单颗粒锆石U-Pb年龄介于210~225 Ma之间。由此可知, 该期花岗岩具有巴颜喀拉构造带碰撞造山后期花岗岩的特征。 |
| 中文关键词:巴颜喀拉群 花岗岩 锆石U-Pb年龄 构造环境 |
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| Geochemical Characteristics and Tectonic Significance of High Aluminium Granites in Diren Area of Zhiduo County, Qinghai Province |
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| Abstract:Granites are distributed in the southern part of the Songpan–Ganzi block in Diren area of Zhiduo County, Qinghai Province. The granites in the study area can be divided into three units: Diren diorite (T3δo), Riqin granodiorite (T3γδ), and Jiaokao porphyry potash feldspar plagioclase granite (T3πηγ), The rock masses exhibit small batholiths and stocks. The granite belongs to aluminum type and has both I and S-type granite characteristics. Eu negative anomalies are obvious, with significant light and heavy rare earth fractionation. Ta, Nb, Ce, Sm, Hf are slightly enriched, Y and Yb are strongly depleted, Rb/Ba ratio is 0.38, and Nb/Ta ratio is 16.44. These data show that the granite has a crustal source rock, partly with the characteristics of molten granite. Single-grain zircon U-Pb ages range from 210 to 225 Ma in the study area. It is thus held that the granite has the characteristics of collision late stage orogenic granite of the Bayankara tectonic belt. |
| keywords:Bayankara Group granite zircon U-Pb age tectonic setting |
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