热梯度处理-XRD法鉴定紫色母岩中层状硅酸盐矿物

Appraisal of Layered Silicate Minerals of Purple Rocks Under Thermal Gradient Treatment by XRD

采用"热梯度"法处理,以处理前后不同种类的标准层状硅酸盐矿物X-射线衍射(XRD)图谱中晶面距d值和峰形变化特征为层状硅酸盐矿物种类的定性依据,鉴定在相同"热梯度"处理条件下紫色母岩中的层状硅酸盐矿物的种类.结果表明:"热梯度"处理前后紫色母岩的XRD图谱差异显著,通过与标准矿物处理前后图谱变化特征比较,能更加准确地确定紫色母岩中部分层状硅酸盐矿物;运用该方法对部分紫色地层的鉴定结果,白垩系夹关组(K1j)红紫色砂岩以蛭石、云母、伊利石、高岭石组合为主;侏罗系沙溪庙组(J2s)灰棕紫色泥岩以云母、伊利石、高岭石、蛭石组合为主;三叠系巴东组(T2b)暗紫色泥岩则以绿泥石、高岭石、云母、伊利石组合为主.

Based on the crystal plane distance d value and the variation characteristics of the peak shape in the XRD(X-ray diffraction)spectra of different standard layered silicate minerals(LSM)before and after 'thermal gradient'treatment,the kinds of layered silicate minerals in purple parent rocks in the same thermal gradient treatment were qualitatively identified.The XRD atlases of purple parental rocks were shown to be obviously different before and after the thermal gradient treatment.By comparing the XRD atlases of purple parental rocks with those of standard layered silicate minerals,we could more accurately determine the LSM in purple rocks.Application of this method to the identification of some of the purple rock layers indicated that vermiculite,mica,illite and kaolinite are the main components of red purple sandstones of K1j,mica,illite,kaolinite and vermiculite are the main components of grey brown purple rocks of J2s,and chlorite,kaolinite,illite and mica are the main components of dark purple rocks of T2b.