论文部分内容阅读
详细研究了大龙山岩体和城山岩体钾长石的铅同位素组成,并参考这些岩体的黑云母化学成分、锶同位素、稀土元素、岩石化学和地球物理资料,发现它们是多阶段侵入的复式岩体,与庐枞火山岩系有渊源关系,属燕山晚期岩浆活动的产物。它们的初始成岩物质来源于上地幔部分熔融,岩浆上升侵位过程中已不同程度地受到了上部地壳的混染。经计算,其中约有61.6％的铅来自上地幔,约有38.4％铅来自上地壳,该区陆壳的乎均年龄约26亿年,陆壳在演化过程中具有富铀的趋势。这些岩体与深大断裂和地幔隆起有成因上的密切联系。
The Pb isotopic composition of the Dalongshan pluton and the Chengshan pluton are studied in detail, and with reference to the biotite chemical composition, strontium isotope, rare earth elements, petrochemistry and geophysical data of these plutons, they are found to be multi-stage intrusive Complex rock mass is related to Luzong volcanic rock series and belongs to the product of late Yanshan magmatic activity. Their initial diagenetic materials originated from the partial melting of the upper mantle and have been contaminated to some extent by the upper crust in the process of magmatic uplifting. About 61.6% of the lead is derived from the upper mantle. About 38.4% of the lead comes from the upper crust. The average age of the continental crust in this area is about 2.6 billion years. The continental crust has a tendency to enrich for uranium during its evolution. These rocks are genetically closely related to deep faults and mantle uplifts.