学术论文

      定量化火成岩结构分析与岩浆固结的动力学过程

      Quantitative textural analysis of igneous rocks and the kinetics and dynamics of magma solidification processes

      摘要:
      定量化火成岩结构分析将传统的定性或半定量化的岩相学研究提高到了与岩石地球化学分析相比拟的定量化程度,实现了诸如晶体粒度分布、晶体空间分布、晶体定向程度分析和二面角测量等方面的定量化研究.集中介绍了以上4种国际上应用广泛的定量化火成岩结构分析方法,包括各种研究方法的基本理论公式、岩浆动力学意义和实现方式.详细介绍了定量化火成岩结构分析中处于核心地位的晶体粒度分布理论,概括了二维岩石薄片法、三维连续剖面法和X射线层析技术,在定量化火成岩结构分析中的应用原理和现状.对晶体粒度分布分析中数据的封闭性和有效性检验进行了简要论述.综合阐述了晶体成核生长,晶体的聚集、分离和分解,岩浆混合,压滤、压熔和岩浆流动,结构的调整和平衡等一些基本的岩浆动力学过程中晶体粒度分布特征的表现.结合一些已发表的晶体粒度分布和晶体空间分布数据,简要概括了重要的基本定量化火成岩结构参数所表达的封闭和开放岩浆体系的特征,以及参数间协变关系所反映的岩浆固结动力学过程.最后给出了二维岩石光薄片分析法的基本流程和注意事项,认为今后定量化火成岩结构分析和地球化学分析结合在一起的综合方法,将成为研究成岩成矿动力学过程的重要手段,也将会逐步扩展到岩浆相关矿床中成岩成矿机制分析和成矿预测的方向.
      Abstract:
      Quantitative textural analysis of igneous rocks has been improving the traditional qualitative and semi-quantitative petrographic methods to a new level that can be compared to geochemical analysis,which includes crystal size distribution(CSD),spatial distribution pattem(SDP),crystal alignment factor,dihedral angle,etc.These quantitative textural analysis techniques and their basic theoretical equations,magma dynamic and kinetic implications and application processes are introduced and summarized in this paper.In particular,the principles and current situations of two dimensional thin sections,serial thin sections and X-ray tomography techniques in quantitative textural analysis are summarized.The closure and validity of crystal size distribution are discussed briefly.Some important kinetics and dynamics of magma solidification processes,including crystal nucleation and growth,crystal accumulation,fractionation and fragmentation,magma mixing,compaction,compaction-pressure-solution and magma flow,textural adjustment and equilibration,are comprehensively elaborated with regard to crystal size distribution.Combined with the published dataset of crystal size distribution and spatial distribution pattern,the characteristics of the closed and open magmatic systems are summarized briefly in terms of the quantitative textural parameters,and the kinetic processes of magma solidification displayed by the correlations of the textural parameters are also presented.Finally the analytical procedures and attentions of the two dimensional thin sections technique are discussed,and it can be concluded that the comprehensive techniques of combining quantitative textural analysis with geochemical analysis would become the important tools for studying the dynamic processes of diagenesis and mineralization,and would also extend to the field of the diagenesis and mineralization mechanisms analysis of magmatic related deposits and ore deposits forecasting in future.
      作者: 杨宗锋 [1] 罗照华 [1] 卢欣祥 [2]
      Author: Yang Zongfeng [1] Luo Zhaohua [1] Lu Xinxiang [2]
      作者单位: 中国地质大学(北京)地质过程与矿产资源国家重点实验室,北京,100083 河南省国土资源科学研究院,河南,郑州,450053
      刊 名: 地学前缘 ISTICPKU
      年,卷(期): 2010, 17(1)
      分类号: P588.114
      机标分类号: V24 TH7
      在线出版日期: 2010年4月12日
      基金项目: 河南省地质矿产重大科技攻关计划项目,国家自然科学基金,国家自然科学基金