XRF法在四川盆地须家河组沉积相研究中的应用

X射线荧光光谱仪在地质样品测定上的应用还不是很广泛，而将X射线荧光光谱法应用到沉积相的研究中则更少。将X射线荧光光谱法(XRF)应用到川中地区上三叠统须家河组二段沉积环境及古气候的识别中，针对四川盆地上三叠统须家河组二段沉积相及沉积环境有争议的问题，特别是须二段地层属于陆相沉积还是海相沉积的问题，采集了四川盆地内四个有代表性地区的须家河组样品，采用X 射线荧光光谱法分析须家河组各段沉积物的元素含量及变化特征，并根据不同相带及沉积环境的元素含量标志，定量分析须家河组沉积相带与沉积环境。研究结果表明： 须家河组二段的Sr/Ba值、Mn/Fe 值和Sr/Ca值均落在陆相沉积的范围内，且与须家河组三-四段的元素含量特征无明显差异，Sr/Cu元素比分析结果表明须家河组沉积时期为温暖—湿润的古气候环境，结果证明四川盆地上三叠统须家河组二段属于温湿气候下的陆相沉积，且与须家河组三-四段沉积环境相类似。X射线荧光光谱法与常规化学分析法实验结果相对误差小于3%，该方法简单易行，为沉积相及沉积环境的识别提供了一种简单、可行且能够定量分析的研究方法。为解决有争议地层沉积相的问题提供了一种较可行的新方法，推动了X射线荧光光谱分析法在地质上的应用。

Application of X-Ray Fluorescence Spectrometry in Xujiahe Formation of Sichuan Basin for the Study of Sedimentary Facies

Currently ,X‐ray fluorescence spectrometer (XRF) is not widely used in the determination of geological samples ,and it’s much less used in the study of sedimentary facies .XRF was firstly used to identify sedimentary environment of the T 3 x2 for‐mation in central Sichuan region .In order to investigate the controversy of sedimentary facies and sedimentary environment of T3 x2 formation of the Upper Triassic in the Central Part of Sichuan Basin ,particularly whether the T 3 x2 formation is continental deposit or marine deposit ,samples were collected in four representative zones from Xujiahe formation in Sichuan Basin .The method of X‐ray fluorescence spectrometry were used to analyze the element contents and its ’ changing characteristics of the dep‐osition from target formation .The sedimentary facies and sedimentary environment of target formation could be quantificationally analyzed by the symbol of corresponding element content .The results of the study show that the ratio of Sr /Ba ,Mn/Fe and Sr/Ca of T3 x2 formation belong to continental deposits ,and it has no significant difference with characteristics of element contents from T3 x3 or T3 x4 .The analysis results about the ratio of Sr /Cu show that the climatic environment of target formation was warm and humid ,and T3 x2 formation was belong to continental deposits in warm and humid environment ,which is similar to the sedimentary environment of T 3 x3 or T3 x4 formation .The relative errors between this method and conventional chemical analysis are less than 3% .The method of X ray fluorescence spectrometry is simple and feasible ,which provides a quantitative analysis method for identification of sedimentary facies and sedimentary environment .The paper provides a new feasible method to solve the controversial sedimentary facies ,which will promote the using of X‐ray fluorescence spectrometric analysis method in geolo‐gy .