Application of natural gamma energy spectrum method for paleobathymetric recovery during carbonate deposition: A case study of M55 sub-member of Guanjiaya section in Xing County of Shanxi Province

The paleobathymetric analysis is of great significance to the paleoenvironment reconstruction and tectonic evolution of the basin. At present, paleobathymetric recovery is mainly qualitative, with high requires of sample reliability and is easy to be limited by the data condition. The natural gamma energy spectrum method has the advantages of accessiblity, low cost and few controlled factors, and can be used to semi-quantitative paleobathymetric recovery based on bathymetric function. However, this method is mostly used in terrestrial clastic rock deposition and its suitability for marine carbonate rock deposition is not clear. Taking the M55 sub-member of Ordovician Majiagou Formation in Guanjiaya section of Ordos Basin as an example, the authors in this paper used the natural gamma energy spectrum method to reconstruct the paleobathymetry of carbonate sediments. This method has good consistency and same results obtained by carbon isotopic method, biological heritage method and rock fabric method. The credibility and practicability of natural gamma energy spectrum method in recovering paleobathymetric recovery was also proven.