Methods for measuring stratigraphic attitude and true thickness based on high-precision 3D real-scene models: A case study of the early Silurian Chongqing Lagerstätte Section, China.

Accurate measurement of stratigraphic attitude and true thickness is critical to geological exploration, mineral resource assessment, and geological disaster prevention. Traditional measurement methods are limited by accuracy and field conditions. With the development of high-precision 3d real-scene modeling technologies, a new solution for these measurements has emerged. This study aims to use high-precision 3D real-scene models to measure stratigraphic attitude and true thickness, and to validate the reliability and practicality. First, high-precision 3D real-scene models were constructed using UAV oblique photography data. Then, we can calculate the normal vector based on three non-collinear points on a plane. We can calculate the attitude and equation of this plane based on the normal vector. The true thickness of strata between two planes was calculated using the formula for the distance from any point on another plane in space to the plane equation. Finally, the methods used to measure the fish fossil-bearing section in Xiushan, Chongqing, China. So, we used this new method to measure 80 stratigraphic joint attitudes and the true thickness of 7 strata. Then, we compared these measurements with 20 stratigraphic joint attitudes and the true thickness of the same 7 strata that we got using traditional methods. The results show that stratigraphic attitude and true thickness obtained using high-precision 3D real-scene models are reliable, and this method can overcome the limitations of traditional measurement methods. This study provides a new method for measuring stratigraphic attitude and true thickness, with good application potential and practical value.