摘要
自生伊利石40Ar-39Ar年代学在油气勘探及其他领域具有重要意义,但由于自生伊利石晶体结构的特殊性,使这一方法从样品处理到数据解释都有一些需要探讨的问题。自生伊利石提纯方法主要由冷冻-加热碎样结合高速离心完成。样品粒度愈细,样品纯度愈大,结晶度愈差。通过X射线衍射可以获得样品纯度、结晶度方面的信息,用TEM可以获得XRD检测限(5%)以下的样品纯度信息。样品39Ar核反冲丢失与样品中晶体的结晶度(2θ)、晶体沿c轴方向的层厚相关;真空包裹技术可以较合理地降低核反冲丢失,得到细粒样品有意义的年龄。真空包裹的细粒样品的"保留年龄"有重要的地质意义。
^40Ar-^39Ar chronology of authigenic illite is significant in the process of exploration of oils and gases and other geological areas. But a large amount of problems have to be discussed from the pretreatment of samples to the interpretation of experimental data for the special structure of the crystal of illite. Purification of authiganic illite is mainly succeeded through heat-freeze circulation and ultrahigh speed centrifugation. Purity of sample is higher, and crystallinity is lower with finer particle size. Messages about purity and crystallinity of samples may be acquired through method of X-ray examination, but small amount of detrital fragments, which is below the detection limit of X-ray examination' may be quantitatively assessed by TEM examination. Recoil loss of ^39Ar is closely associated with crystallinity (20) and particle size perpendicular to c axis. Vacuum encapsulation of samples may decrease recoil loss of Ar apparently, thus the meaningful age of the fine particle size sample may be obtained. And the "retention age" of vacuum encapsulated fine particle size samples has geological significance.
出处
《矿物岩石地球化学通报》
CAS
CSCD
2008年第2期169-174,共6页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家重点基础研究发展规划项目(2005CB422100)