滇西昌宁-孟连带硅质岩的阴极发光特征及其意义

CHARACTERISTICS AND SIGNIFICANCE OF CATHODOLUMINESCENCE OF SILICEOUS ROCKS IN CHANGNING-MENGLIAN BELT,SOUTHWESTERN YUNNAN

阴极发光手段在恢复碳酸盐岩和砂岩的原始结构构造、成岩及孔隙演化等方面已显示出独特作用，而用于地层学研究较少。硅质岩多为自生成因，常由非晶质或隐晶质ＳｉＯ２ 矿物组成，多数在成岩中发生重结晶作用，通常在低能（＜ ２０ ０００ ｅＶ）阴极射线下发光很弱，常被研究者们忽视。通过对滇西昌宁－ 孟连带晚古生代硅质岩的高能（２５ ０００ｅＶ）阴极发光及相关研究表明：自生或重结晶的硅质岩（含放射虫化石）（石英）发光明显，其发光强弱和发光特征与Ｆｅ，Ｃｏ，Ｎｉ和Ｍｎ，Ｃｒ，ＲＥＥ质量分数有直接关系，并受地层的沉积－ 构造背景控制。

Cathodoluminescence (CL) analysis plays a unique role in restoring the original texture, structure, diagenesis and pore evolution. However, it has been rarely applied to the study of stratigraphy. Most siliceous rocks are of autogenetic origin and composed of noncrystalline or cryptocrystalline SiO 2 minerals which are mostly recrystallized in diagenesis process. The CL of siliceous rock is very weak under the candition of low energy (<20 000 eV) and therefor, is often neglected by researchers. The high energy (25 000 eV) CL analysis on the siliceous rock of late Paleozoic in Changnin-Menglian belt shows that the luminescence of the autogenetic or recrystallized siliceous rock (with radiolarian and quartz) is evident. Their luminous ability and characteristics are directly related to the contents of Fe, Co, Ni, Mn, Cr and REE, and are controlled by background of sedimentation and tectonics of the strata, which are of significane for the research of stratigraphic division and stratigraphic framework in the orogenic belts.