中酸性火山岩中造岩矿物含量的定量计算方法

The quantitative calculation method of the petrogenetic mineral content in intermediate-acid volcanic rock.

主要造岩矿物的含量是火山岩分类定名的主要依据。对于基质为微晶质、隐晶质的火山岩,采用常规的薄片显微镜统计矿物含量几乎是不可行的。目前已有的利用岩石化学成分计算矿物含量的方法均不适用于中酸性火山岩。因此,本文基于岩石与矿物之间的化学成分质量平衡原理,提出了计算火山岩实际矿物含量的方法。该方法是利用实际矿物成分,采用最优化方法计算岩石中实际矿物的含量,在很大程度上避免了计算中的人为性。对中酸性火山岩实际样品计算表明,该方法使用简单方便,精度较高。

Assorting and naming of volcanic rock is mainly based on the content of main petrogenetic mineral. It is infeasible for the volcanic rock with microcrystalline and cryptocrystalline matrix to count its mineral content by conventional slice method. Although some methods have been presented using chemical composition of rock to calculate mineral content, they are unsuitable for the intermediate-acid volcanic rock. A method to calculate practical mineral content of volcanic rock is given based on the mass balance of chemical composition between rock and its mineral. Based on the chemical composition of natural mineral, optimization method is used to calculate practical mineral content and the artificialness in calculation is avoided to a great extent. The method is demonstrated to be portable and with high precision by practice samples of intermediate-acid volcanic rock.