张 蒙1,李 俊1,谢恩彩2,吕品翰1.滇西龙陵平达花岗岩体成岩时代及其地球化学特征[J].有色金属(矿山部分),2019,71(4):64-70.
滇西龙陵平达花岗岩体成岩时代及其地球化学特征
Diagenetic epoch and geochemical characteristics of Pingda granite in Longling, western Yunnan
  
DOI:10.3969/j.issn.1671-4172.2019.04.013
中文关键词:  平达  白垩纪花岗岩  高钾钙碱性系列  负异常
英文关键词:Pingda  cretaceous granite  the characteristics of high potassium calc-alkaline series  negative anomaly
基金项目:云南永昌铅锌股份有限公司与昆明理工大学校企合作项目(KKK0201721042)
           
作者单位
张 蒙1 (1. 昆明理工大学,昆明650000
2. 云南永昌铅锌股份有限公司,云南 保山678307)
李 俊1 (1. 昆明理工大学,昆明650000
2. 云南永昌铅锌股份有限公司,云南 保山678307)
谢恩彩2 (1. 昆明理工大学,昆明650000
2. 云南永昌铅锌股份有限公司,云南 保山678307)
吕品翰1 (1. 昆明理工大学,昆明650000
2. 云南永昌铅锌股份有限公司,云南 保山678307)
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中文摘要:
      滇西龙陵平达地区的花岗岩体主要是加里东运动早期以及燕山—喜山期岩浆活动形成的岩浆响应。通过应用实验仪器ME-XRF26d X射线荧光光谱仪、ME-MS81电感耦合等离子体质谱完成对花岗岩样品的主量元素、稀土元素以及微量元素的测定。在该研究区内,岩性以花岗岩、花岗闪长岩为主,SiO2含量平均70.9%,Al2O3含量13.8%~18.2%,K2O含量为3.39% ~5.83%,Na2O平均含量2.48%,显现出“富硅、高铝—钠、高镁—钾”,高钾钙碱性系列的特点,属于过铝质花岗岩;稀土元素总量偏高,平均137×10-6,轻重稀土元素比值在1.52~8.2,分馏较为强烈,轻稀土含量介于32×10-6~197×10-6,相对富集,重稀土范围为14.4×10-6~65.8×10-6,相对亏损,Eu显现出明显的负异常特征,曲线向右倾;同时Sr=0.1×10-6 ~ 136×10-6,Yb平均1.9×10-6,符合低Sr低Yb的特征,即花岗岩在低或者中等压力下形成,可能为碰撞作用有关的钙碱性花岗岩。结合前人的研究成果,对该区晚中生代花岗岩开展系统的岩相学、矿物学、锆石U-Pb测年等研究,为未来整个龙陵地区花岗岩体的研究工作提供参考。
英文摘要:
      The granite bodies in Pingda area of Longling, western Yunnan are mainly the early Caledonian movement and the magmatic response formed by Yanshanian-Himalayan magmatism. The main elements, rare earth elements and trace elements in granite samples were determined by ME-XRF26d X-ray fluorescence spectrometer and ME-MS81 inductively coupled plasma mass spectrometry. In the study area, the main lithology is granite and granodiorite. The average SiO2 content is 70.9%, Al2O3 content is between 13.8% ~18.2%, K2O content is 3.39% ~5.83%, the average Na2O content is 2.48%, showing the characteristics of “Rich in Silicon, High Aluminum-Sodium, High Magnesium-Potassium”. The characteristics of high potassium calc-alkaline series belong to peraluminous granite. The total amount of REE is on the high side, with an average of 137×10-6, ratio of LREE and HREE in 1.52~8.2, with a relatively strong fractionation. LREE content is between 32×10-6~197×10-6 with relatively rich; and HREE range is 14.4×10-6~65.8×10-6 with relative deficit. Eu shows a significant negative anomaly, the curve to the right; meanwhile Sr=0.1×10-6~136×10-6, Yb averaged 1.9×10-6, which is in line with the characteristics of low Sr and low Yb, which refers to that granite is located at low pressure or formed under moderate pressure, it may be a collision-related calcium-alkali granite. Based on the previous research results, systematic lithofacies, mineralogy and zircon U-Pb dating of the Late Mesozoic granite in this area were conducted in this paper, which canprovide reference for the future research work of the granite body in Longling area.
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