【摘要】 本文通过理论推导获得了十二种成岩过程的比值—比值、元素—元素、比值—元素、分母(和分子)相同的比值一比值的协变方程。同时指出:(1)要正确判别协变图形必须尽可能选择多种元素和不同坐标,作出一系列图解进行综合分析;(2)协变图形的应用仅限于排除那些与此图形不相吻合的成岩过程。协变图必须结合地质实际才能获得满意的结果。更多还原

【Abstract】 Through theoretical calculations, trace-element covariance plots of twelve kinds of different petrogenetic processes have been obtained. Each petrogenetic model yields plots of five different coordinates: ratio versus ratio, element versus element, ratio versus element, ratio versus ratio of the same denominator and ratio versus ratio of the same numerator. The curves of the covariance plots have three shapes. straight line, hyperbola and power curve. Since they may transform each other under given conditions, it is not reliable to judge the curve shapes only using individual covariance plots. It is necessary to choose as many elements as possible and different coordinates to construct a series of covariance plots for a comprehensive analysis.Each petrogenetic process corresponds with given covariance plots, but different petrogenetic processes can produce the same plots, so when the covariance plot is used in judging petrogenetic processes, one fails to obtain accurate results, but only can get rid of those petrogenetic processes that are not coincident with the plots. Satisfactory results can be obtained only by combining the covariance Plots with actual geological situation.更多还原