声波时差法计算地层剥蚀量问题的斧正

Correction of erosion thickness of strata calculated by acoustic time difference

针对国内学者用声波时差法计算地层剥蚀量存在的种种问题,从Magara法原理入手,通过公式推演和定量测算分析,认为有学者提出的用新沉积地层的压力与剥蚀地层在相同点的压力大小比较作为判别是否适用Magara法,其观点虽然合理,但实际这样的窗口狭小或不存在都难断定,不具有操作性和实际价值;Magara法原有的剥蚀地层厚度必须大于新沉积地层厚度的准则是正确的,把使用范围扩展到新沉积地层厚度大于剥蚀地层厚度是不妥的。同时,指出了声波时差法应用中存在的诸多问题,逐一加以斧正。分析指出,声波时差法、古温标法都不适合计算苏北盆地地层剥蚀量,现有文章都有原理、方法和基础资料等错误,剥蚀量数据与盆地地质完全不吻合,结论不可用。

There are some problems in calculating erosion thickness with acoustic time difference.Based on the principle of Magara＇s method,combined with deducing formula and quantitative analysis of measuring results,it is considered to be no opera-tional and practical value for distinguishing the applicability of the Magara＇s method by comparing the pressures of new and ero-ded sediment strata at the same point.Although the viewpoints of the method sound reasonable,its window is too narrow,even it is difficult to determine its existence.It is reasonable that the eroded sediment strata thickness must be greater than the new one in Magara＇s method,but the expanded scope of application that the eroded sediment strata thickness is smaller than the new one is improper.At the same time,the problems in the application of acoustic method are pointed out and corrected one by one.The study results showed that the acoustic difference method and the geothermometer method are not suitable for estimating the ero-sion strata thickness of Subei Basin;the published articles have errors of principle,method and basic data,etc.,in which the ero-sion data do not match the geological conditions of Subei Basin,and the conclusions can not be used.