臺灣低度變質碎屑岩區以伊萊石為主要的黏土礦物，本研究利用岩象學及X光繞射分析方法探討伊萊石的類型與其結晶度的關係，作為熱液作用影響低度變質碎屑岩的依據。
本研究結果指出硬頁岩區的伊萊石屬於1Md形，雲母礦物直徑42.2 μm-115 μm，其伊萊石結晶度值為0.536-0.701 Δ°2θ；及2M+1Md形，雲母礦物直徑30.8 μm-115 μm，其伊萊石結晶度值為0.469-0.586 Δ°2θ。板岩區的伊萊石屬於1Md形，雲母礦物直徑63.5 μm-142 μm，其伊萊石結晶度值為0.374-0.379 Δ°2θ；及2M+1Md形，雲母礦物直徑34.1 μm-231 μm，其伊萊石結晶度值為0.357-0.606 Δ°2θ。紅柴林地區的伊萊石屬於2M形，雲母礦物直徑19.2 μm-545 μm，其伊萊石結晶度值為0.218-0.468 Δ°2θ。當岩石受到熱液作用影響之下，會使2M+1Md形轉變為1Md形，但是，伊萊石結晶度值沒有太大變化。
There is mainly composed of illite in the low-grade meta-clastic rock of Taiwan. This study used the petrography and X-ray diffraction to analyze the illite type and their crystallinity as the indictor about hydrothermal alteration affect low-grade meta-clastic rock.
The results of this study shown that the argillite area belongs to 1Md and 2M+1Md, the mica sizes of former samples are 42.2 μm-115 μm, and their illite crystallinity are 0.536-0.701 Δ°2θ, however, the latter samples are 30.8 μm-115 μm, and their illite crystallinity are 0.469-0.586 Δ°2θ. In the slate area, it has two illite types including 1Md and 2M+1Md. The mica sizes of former samples are 63.5 μm-142 μm, and their illite crystallinity are 0.374-0.379 Δ°2θ, and then the latter samples are 34.1 μm-231 μm, and their illite crystallinity are 0.357-0.606 Δ°2θ. In the HongTaiLing, it is 2M type for all samples, their mica sizes are 19.2 μm-545 μm, their illite crystallinity are 0.218-0.468 Δ°2θ. The 2M+1Md type of the sample would be changed to 1Md by way of the hydrothermal interaction with low-grade meta-clastic rock, but their illite crystallinity doesn't varies.
