ABSTRACT
One of the most distinguished sandstone geoheritage resources in the Khorat Plateau is Hin Chang Si located in the Nam Phong National Park, Khon Kaen Province. The clastic sedimentary rocks of the Phra Wihan Formation of the Khorat Group covered this area. As a result of the lithologic study, the Hin Chang Si consists of pebbly sandstone, moderately sorted medium- to coarse-grained sandstone, and a small amount of siltstone interbedded with laminated shale. The characteristics (colors, cementation, and degrees of weathering) divided sandstones into two groups, including white grain-supported sandstone with silica cement and matrix-supported sandstone with Fe-rich cement. In addition, these sandstones present primary sedimentary structures, which comprise tabular cross-bedding and normal grading as well as bioturbation. Hin Chang Si demonstrates many geomorphological features, including cliffs, potholes, rock pillars, polygonal cracks, caves, tafoni, runnels, and natural arches according to inventory. The weathering and degradation processes in humid tropical conditions are the main processes that caused these geomorphological features. Whereas many primary factors affected various types of morphology that are composed of joints, folds, and faults. The national park provides the natural trail map, tourism information, and biodiversity data to visitors; however, geological information about sandstone landforms should be actualized for geotourism development.