关键词: 岩石结构, 代表性样品, 矿物含量, 矿物粒径, 花岗质岩石, 斑晶

Abstract: In order to obtain the size of representative samples and its constraints, the relationships of the representative samples with crystal contents and crystal size are preliminarily discussed by statistical simulations of the holocrystalline rocks’texture and the idealized granitic compositions. The maximum possible difference between the original and measured crystal contents of samples, and the size of representative samples are determined under the variations of crystal contents and size. The greatest difference between the original and measured crystal contents of samples can be obtained by counting the number of phenocrysts across the sections of samples. The size of representative samples can be acquired by using the average crystal size. The deviation between the measured and original crystal contents are much more higher for coarse-grained samples with the same sample size. The largest representative samples are needed when the crystal content reach 20% for phenocrysts or coarse-grained minerals in equigranular texture. Finally, two examples including the Mapeng and Fangshan intrusions are used to examine the validity and practicability.

Key words: rock textures, representative samples, crystal contents, crystal size, granitic rocks, phenocryst