Natural fracture system in Khorat group, Thep Sathit district, Chaiyaphum province

Abstract

Cliff top land or Phasudpandin is tourist attraction in Thep Sathit District, Chaiyaphum Province. There are two remarkable features in Phasudpandin. One is the feature of cliff and the other is systemic fractures scattered throughout the cliff. Geological event, that is a cause of cliff lifting, is described on the board in Phasudpandin. Unfortunately, the content on the board isn’t consistent with current geological knowledge and there is no information about systematic fracture. Observed from Digital elevation model, there are a lot of fractures scattered throughout the western boundary of Thep Sathit district, which seem to be related with systematic fracutures in Phasudpandin. In this study, field study, digital outcrop model, and digital elevation model were used to create fracture map and propose a conceptual model for fracture development of Khorat Group in western part of Thep Sathit district, Chaiyaphum province. Results from this study show that there are 3 main orientations and types of fracture scattered throughout the area: ENE-WSW (sinistral), WNW-ESE (dextral) and N-S (extension fracture). The orientations and types of fracture imply that these fractures are caused by maximum compressive principle stress in N-S direction which is a result of collision between India plate and Eurasia plate in Paleogene. This compression is also a cause of faulting and uplifting along western margin of Thep Sathit district. The compression direction suggests that fault along western margin of district is sinistral strike-slip fault.