Research on the geological and geodynamic conditions forming the Dong Van valley and the relationship with hydrogeological features in the area of Dong Van city, Ha Giang province

Abstract

    This paper presents results on the geological, geodynamics conditions and tectonic evolution process of the Dong Van valley based on the analysis and statistics of physical tectonic parameters on the fault surface and fractures. The study area belongs to the main heritage area of UNESCO Global Geopark Dong Van Karst Plateau, which is located in the north of Vietnam and belongs to the extended part of the South China Karst Belt (Yunnan Karst Plateau). The obtained results show that the Dong Van tectonic valley is controlled by two fault systems developing in the NW-SE direction and formed in the Cenozoic. The formation of this valley and the controlling factors were formed in the Eocene-Miocene, while the Pliocene-Quaternary is the period of extension and completion of the Dong Van valley according to the pull-apart mechanism. From the hydrogeological point of view, the main aquifer of this region is the Bac Son limestone aquifer, which is highly fractured, and the aquitard layer is a set of red-veined limestone of the Toc Tat Formation. Although there are still limitations due to accessibility and the sparse number of survey points, this study suggests that analysis, statistics and modeling of physical tectonic data is one of the effective approaches used to determine the tectonic evolution process in karst regions.