The Study of Stratigraphic Integrity of Marine (Lake) to Terrestrial Transitional Clastic Rocks Based on 2D Flume Experiments

This study aims to simulate the sedimentary processes of marine (lake) to terrestrial transitional clastic rocks and quantitatively analyze the impact of geological control factors on stratigraphic integrity. Most sedimentary strata exhibit discontinuities of different scales, represented by both temporal and spatial incompleteness. Defining and quantitatively characterizing "stratigraphic integrity" is of great importance for accurate stratigraphic correlation, reconstructing the depositional history of geological periods, and guiding oil and gas exploration.

2D physical water tank experiments can realistically simulate geological processes such as erosion, transport, deposition, and reworking of clastic materials. These experiments allow for the calculation of stratigraphic integrity at any given location. In this study, a narrow 3D water tank was used to approximate the 2D sedimentary processes, simulating the entire sedimentary sequence of marine (lake) to terrestrial transitional clastic rocks and calculating stratigraphic integrity.

A transparent glass water tank (1.5m×0.5m×0.05m) was chosen as the experimental setup. Based on a thorough review of relevant literature, multiple sedimentary bottom shapes were designed to replicate different real-world geological depositional environments. Specific time steps were set to quantitatively introduce different types of quartz sand, achieving visualization of the experimental results. A water level control curve was designed to change the water level over time, allowing for precise control of water height in the tank and effectively simulating the evolution of stratigraphic sequences. Finally, based on the experimental data, stratigraphic integrity was calculated for various depositional environments, enabling further analysis of the experimental results.

The experimental results clearly reveal the evolution of stratigraphy and depositional sequence features, which closely match actual geological conditions. This indicates that the experiment can realistically simulate the sedimentary processes of marine (lake) to terrestrial transitional clastic rocks. From an overall perspective, erosion near the sediment source is more pronounced and frequent, while at the distal end, the strata remain more complete due to prolonged subaqueous conditions, and erosion is less noticeable. The depositional sequence shows a typical progradation pattern, with thin oblique and wavy bedding structures. Stratigraphic integrity studies show that the integrity increases from the proximal to distal end. A comparison of integrity at the same location shows that horizontal surface fluctuations have a much stronger impact on stratigraphic integrity than changes in the bottom shape, with frequency variations in the water level control curve having a greater effect than changes in amplitude.

This study uses 2D physical water tank experiments to simulate and reconstruct the sedimentary processes of marine (lake) to terrestrial transitional clastic rocks. It also quantifies the influence of geological control factors on stratigraphic integrity. The results demonstrate that both the sedimentary bottom shape and water level change curves affect stratigraphic integrity, with water level changes having a more significant impact. This research is the first to combine 2D water tank simulations with stratigraphic integrity control factors, providing innovative experimental methods and technical tools for sedimentary physical modeling and stratigraphic integrity assessment.