Interactive Stratigraphic Forward Simulation: An Open-Source Toolkit for Marine Geoscience Education

Forward stratigraphic modeling computes the stratigraphic response of sedimentary basins to sea-level change, tectonic subsidence, and sediment supply, and interactive simulation brings this capability into the sequence stratigraphy classroom, where connecting dynamic forcing to static architectures—progradation, retrogradation, and aggradation—is a persistently documented learning difficulty. Existing software, however, is polarized between costly commercial packages and research-grade open-source codes that demand substantial programming skills. This paper presents Sedapp-Py, a complete pure-Python 3.11 port of the open-source, R-based Sedapp nonlinear diffusion forward stratigraphic model, together with the Sedapp Teaching Studio, an interactive graphical teaching environment built around the engine. The port preserves the original model’s dual-lithology sand–mud transport, negative-feedback sediment-supply regulation, differential deposition–erosion efficiency, Athy-law compaction, and isostatic adjustment while removing the R dependency; the engine is fully deterministic and completes the 400 Ma reference simulation on the order of seconds, enabling real-time classroom experimentation. Comparison with the published reference case reproduces the backstripped template basin with a maximum fill thickness of 1452 m versus 1486 m (≈2.3% deviation), a fill-thickness RMSE of 119.5 m, and a depocenter offset of 450 m against the backstripped template (a consistency check, since the template and the subsidence input share provenance). A publication-quality didactic figure system—three-attribute cross-sections, Wheeler diagrams, shoreline trajectories, synthetic well logs, and supply-by-transport sensitivity matrices—is generated by a single reproducible script (fixed seed 42). Three documented teaching scenarios—a marine ramp under a sinusoidal eustatic cycle, a stacking-pattern laboratory, and a petroliferous basin case—demonstrate how slider-driven parameter manipulation makes the accommodation–stacking-pattern linkage directly observable. Sedapp-Py is, to the authors’ knowledge, the only actively maintained, open-source, GUI-equipped tool of its kind in the modern Python ecosystem, and it provides a reproducible foundation for classroom deployment and future learning-efficacy studies.