本研究以不同量化方法分析板岩、粉砂質板岩及變質砂岩之岩象,並結合黏土礦物種類及伊萊石結晶度值,予以了解武界地區低度變質岩的變質變形特徵。
本研究結果顯示,變質砂岩劈理領域百分比小於20%,夾質領域的石英顆粒邊界圓曲狀平均為30%,縫合狀比例平均為70%。粉砂質板岩劈理領域的百分比分布於30-80%,夾質領域的石英顆粒邊界圓曲狀平均為67%,縫合狀平均為33%。板岩劈理領域的百分比達85%以上,夾質領域的石英顆粒邊界圓曲狀平均為91%,縫合狀比例平均為9%。另外,從褶皺地區的軸部及翼部分析結果顯示,本研究區域變質砂岩劈理百分比小於5%,然而,其伊萊石結晶度值遠低於板岩和粉砂質板岩,且變質砂岩的黏土礦物大多僅由伊萊石礦物所組成,因此,判斷變質砂岩的伊萊石結晶度值較其他岩性來得低的主要原因是受到變質砂岩中雲母類礦物控制。
This study applies methods of different quantitative on the petrography of slate, silty slate and meta-sandstone, and integrates clay mineral assemblages and illite crystallinity. The purpose is to understand the characteristics of low grade metamorphic rock in the Wuji area.
The results show that the percentage of cleavage domain and quartz grain boundary in meta-sandstone, silty slate and slate. In the meta-sanstone, they have cleavage domain of less than 20%, curve and suture boundaries of quartz grain of 30% and 70% in the microlithon domain, respectively. In the silty slate, cleavage domain is about 20%-80%, and that is 67% and 33% in the curve and suture boundaries of quartz grain of microlithon domain, respectively. In the slate, it has more than cleavage domain of more than 85%, and curve and suture boundaries of quartz grain have 91% and 9%, respectively. In addition, this study displays that the mica minerals is an important factor, and causes lowest illite crystallinity of meta-sandstone in the fold areas of Wuji area.