将数字信号分析中常用的傅里叶变换引入地质剖面分析中,从信号分析的角度,把同一地区不同时代剖面线分别看作一维连续的空间域信号,并对其傅里叶变换后频谱进行分析研究,也可以借助自仿射分形模型,依托于功率谱来计算不同时代剖面线的分维值。对不同时代剖面线的频谱分析,可得到相应剖面线所包含的频率信息,并可以实现不同时代地质剖面线的数学表达。对比分析同一地区不同时代剖面的频谱,探究不同时代剖面线频谱特点。本文以南海西沙群岛局部剖面为例,分别对相同地段的海底、上新世、晚中新世、中中新世、早中新世、基底界面及相邻界面间厚度进行了频率域上的对比分析,发现不同时代剖面线在频率域整体趋势上存在一定的相似性,相对低频成分相似性影响贯穿各个时代,相对高频成分不同时代剖面线存在差异。不同时代剖面线的分维值各不相同,总体呈现单增趋势。这些频谱和分维值特点与西沙地区渐趋稳定的构造背景相对应,表明西沙海域地貌将以较为平稳的趋势发育。
Each section line of a certain period in a geological profile is a continuous and unidimensional signal in space. The frequency spectrum of this signal can be obtained by using the Fourier Transform. In addition, fractal dimension of the section line can be calculated according the self- affine fractal model. Through the analysis of the frequency spectrum and fractal dimension of different section lines at different ages, more geological information will be presented and revealed. In this paper, a seismic reflection profile from Xisha Island of the South China Sea was taken as an example. Section lines of the sea floor, Pliocene, Late Miocene, Middle Miocene, Early Miocene, and the basement were contrasted in the frequency spectrum by using the Fast Fourier Transform. Results showed that the frequency spectrum of these section lines was somewhat similar in trend, where the relatively low frequency component ran throughout all ages and major diversity was in the relatively hig
