CAJ | 학술논문

利用LA-MC-ICPMS对陡水岩体中细粒黑云母二长花岗岩中的锆石开展了U-Pb同位素测试,获得206Pb/238U年龄为460.8±1.5 Ma(n=10, MSWD=0.78),属华南加里东晚期第一次岩浆活动峰期的产物。陡水花岗岩显示高硅(SiO2平均含量为78.37%),富钾(K2O>Na2O)的特征, A/CNK 平均值1.17,属于高硅高钾过铝质花岗岩。其稀土总量偏低(平均为90.68μg/g),稀土元素球粒陨石标准化配分图具有M型四分组效应,强烈的Eu负异常；明显亏损Ba、Sr、Ti、P元素。相对于已知含稀土矿的和具有寻找稀土矿潜力的加里东期岩体来说,陡水岩体可能不具备形成稀土矿的能力。通过对南岭地区已确认的加里东期花岗岩体的地球化学资料对比分析,认为华南地区加里东期花岗岩对离子吸附型稀土矿床的形成有很大贡献,在今后的找矿工作中应给予重视。
이용LA-MC-ICPMS대두수암체중세립흑운모이장화강암중적고석개전료U-Pb동위소측시,획득206Pb/238U년령위460.8±1.5 Ma(n=10, MSWD=0.78),속화남가리동만기제일차암장활동봉기적산물。두수화강암현시고규(SiO2평균함량위78.37%),부갑(K2O>Na2O)적특정, A/CNK 평균치1.17,속우고규고갑과려질화강암。기희토총량편저(평균위90.68μg/g),희토원소구립운석표준화배분도구유M형사분조효응,강렬적Eu부이상；명현우손Ba、Sr、Ti、P원소。상대우이지함희토광적화구유심조희토광잠력적가리동기암체래설,두수암체가능불구비형성희토광적능력。통과대남령지구이학인적가리동기화강암체적지구화학자료대비분석,인위화남지구가리동기화강암대리자흡부형희토광상적형성유흔대공헌,재금후적조광공작중응급여중시。
The Doushui granitic pluton situated in Shangyou county, Jiangxi province, is among the first recognized Caledonian granites in South China according to their geological occurrences, and no isotopic dating result has been reported yet. Zircon grains from the Doushui granite were analyzed using Laser Ablation-Multicollector Inductively Coupled Plasma-Mass Spectrometer (LA-MC-ICPMS) method, which yield a U-Pb age of 460.8±1.5 Ma. This age confirms that the granite was intruded in the Middle Ordovician, which was products of the first peak period of magmatism during the Late Caledonian period in southern China, indicative of a new cycle of folding and orogen. Comparing with the other rare earth bearing Caledonian granitoids in the Nanling region, the Doushi granite is unlikely to form ion exchangeable REE deposit.