选取塔里木东北部的笔架山二叠纪火山岩带为研究对象，通过年代学、岩石学和地球化学等研究，论证火山岩的亲缘关系以及火山岩与侵入岩的关系，探讨岩浆演化过程与源区性质。笔架山一带二叠纪火山岩分布于笔架山镁铁质超镁铁质岩带北侧...选取塔里木东北部的笔架山二叠纪火山岩带为研究对象，通过年代学、岩石学和地球化学等研究，论证火山岩的亲缘关系以及火山岩与侵入岩的关系，探讨岩浆演化过程与源区性质。笔架山一带二叠纪火山岩分布于笔架山镁铁质超镁铁质岩带北侧。火山岩的岩石类型主要有玄武岩、玄武质安山岩、安山岩、英安岩和流纹岩。流纹岩的 LA ICP MS锆石 U Pb年龄为（285．0＆#177;2．9）Ma，属二叠纪乌拉尔世。该火山岩多属拉斑玄武岩系列。玄武岩、玄武质安山岩、安山岩的岩石学及地球化学特征表明，它们都是由拉斑玄武质岩浆通过分离结晶作用演化而成，玄武岩岩浆在上升过程中经历了一定程度的同化混染作用。玄武岩的w（TiO2）（2．35％～3．81％）、w（TFeO）（10．59％～13．87％）、w（P2 O5）（0．35％～0．50％）高，属于高钛玄武岩系列，富集轻稀土元素和大离子亲石元素，Nd Sr同位素组成具有 OIB亲和性，地球化学特征显示出玄武岩的岩浆源区属尖晶石稳定域。笔架山二叠纪侵入岩和火山岩的时空关系、岩石地球化学特征和岩浆演化程度的研究表明：二者是同源岩浆分异的产物，岩浆进入现存岩浆房后，大量的堆晶相形成了镁铁-超镁铁质侵入岩，而演化的岩浆沿岩浆房顶部或旁侧的断层带溢出而形成基性中性火山岩；酸性火山岩是由幔源岩浆的热量引起地壳重熔形成的。展开更多
Hegyi’s competition index model for individual tree was introduced to study intraspecific and interspecific competition for dominant population of evergreen broad\|leaved forest in Bijia Mountain of Longyan, Fujian. ...Hegyi’s competition index model for individual tree was introduced to study intraspecific and interspecific competition for dominant population of evergreen broad\|leaved forest in Bijia Mountain of Longyan, Fujian. The results show that the competition is more intense in intraspecies than in interspecies, which indicated indirectly that the horizontal spatial pattern of dominant populations conform to aggregated distribution. There existed difference in interspecific competitions, and the competitions can be divided into four groups according to the competition index. Relationship between the competition index and the base diameter of objective tree conformed closely to power function, and competition intensity reduced with the growth in base diameter of objective tree.展开更多
文摘选取塔里木东北部的笔架山二叠纪火山岩带为研究对象，通过年代学、岩石学和地球化学等研究，论证火山岩的亲缘关系以及火山岩与侵入岩的关系，探讨岩浆演化过程与源区性质。笔架山一带二叠纪火山岩分布于笔架山镁铁质超镁铁质岩带北侧。火山岩的岩石类型主要有玄武岩、玄武质安山岩、安山岩、英安岩和流纹岩。流纹岩的 LA ICP MS锆石 U Pb年龄为（285．0＆#177;2．9）Ma，属二叠纪乌拉尔世。该火山岩多属拉斑玄武岩系列。玄武岩、玄武质安山岩、安山岩的岩石学及地球化学特征表明，它们都是由拉斑玄武质岩浆通过分离结晶作用演化而成，玄武岩岩浆在上升过程中经历了一定程度的同化混染作用。玄武岩的w（TiO2）（2．35％～3．81％）、w（TFeO）（10．59％～13．87％）、w（P2 O5）（0．35％～0．50％）高，属于高钛玄武岩系列，富集轻稀土元素和大离子亲石元素，Nd Sr同位素组成具有 OIB亲和性，地球化学特征显示出玄武岩的岩浆源区属尖晶石稳定域。笔架山二叠纪侵入岩和火山岩的时空关系、岩石地球化学特征和岩浆演化程度的研究表明：二者是同源岩浆分异的产物，岩浆进入现存岩浆房后，大量的堆晶相形成了镁铁-超镁铁质侵入岩，而演化的岩浆沿岩浆房顶部或旁侧的断层带溢出而形成基性中性火山岩；酸性火山岩是由幔源岩浆的热量引起地壳重熔形成的。
文摘Hegyi’s competition index model for individual tree was introduced to study intraspecific and interspecific competition for dominant population of evergreen broad\|leaved forest in Bijia Mountain of Longyan, Fujian. The results show that the competition is more intense in intraspecies than in interspecies, which indicated indirectly that the horizontal spatial pattern of dominant populations conform to aggregated distribution. There existed difference in interspecific competitions, and the competitions can be divided into four groups according to the competition index. Relationship between the competition index and the base diameter of objective tree conformed closely to power function, and competition intensity reduced with the growth in base diameter of objective tree.
