Discover the volcanic geological heritage in Dong Nai

Volcanic cave in Phu Tan commune, Dinh Quan district

Protecting and exploiting heritage values for human purposes is essential.

Many caves and craters

The report on field survey results of volcanic caves in Tan Phu district, Dinh Quan district areas of the Southern Geological Map Federation showed that 5 volcanic caves were found. .

M.A. Thai Quang, former head of the Southern Federation of Geological Maps, Head of the survey team said: “Among the 5 surveyed caves, there is a cave located at the foothills of Phu Loc commune (Tan Phu district) which is quite beautiful. The surface of the cave is red powdery clay weathered shell and natural rocks with holes. The mouth of the cave connects to the ground by two subsidence pits. Inside has a height of 4-6m, width of 11m. The remaining remnants of volcanic activity are cave walls with ledges caused by solidified lava flows to form stalactites.

The cave with the largest scale, the most beautiful landscape according to the survey team's assessment is Bat cave in Phu Tan commune (Dinh Quan district). The cave is located in the tea tree forest, about 200m from National Highway 20, so you can ride a motorbike to the place. The surface of the cave has many large rocks stacked to form an inclined surface, convenient to go up and down. The cave has a length of about 430m excluding branches, the widest part is more than 10m, 3-4m high. The cave is made of solidified lava blocks that form a solid protective layer. When shining the flashlight on the cave wall, there is a beautiful iridescent reflection.

According to Mr. Thai Quang, based on the structure and geology, it is possible to know that these caves formed from the Neogene - Quaternary period (about 2.5 million years ago). During the volcanic tectonic process, lava spewed up to form a crater, the surface was cooled but still molten underneath, creating long-running caves in the ground.

Not only the mountainous districts, there are also volcanic caves in Bau Ham commune (Trang Bom district). According to Mr. Mai Cong Khien, Department of Water Resources, Minerals and Climate Change (Department of Natural Resources and Environment), the volcanic cave in Bau Ham commune has a dome about 10m high and 20m wide. The ceiling and walls of the cave are composed of porous basalt with traces of lava flow. The mouth of the cave is located just a few dozen meters from the house.

Before the information was available, in 2013, a survey team consisting of scientists from Germany and Vietnam also released information that the area of Tan Phu district, Dinh Quan district had 11 lava caves, with a total length of 1.8km. Each cave has a different structure, scattered in areas with hills, geologically active.

Geological and historical documents also record that the area has funnel-shaped, inverted cone craters. A special feature is the craters located on the tops of hills and mountains like large basins.

Hill No. 19, where there is a large crater located in the area of Dinh Quan district

It is necessary to have statistics and conservation of geological heritage

Caves and craters are geological heritage of scientific and historical value. The formation process takes a long time, is easily destroyed but cannot be regenerated. Therefore, it is necessary to study and evaluate as a whole, thereby giving a reasonable protection and exploitation solution.

According to Mr. Thai Quang, the above statistical results are only preliminary information because the project is implemented on a narrow scale and in a short time. Dong Nai or Ministry of Natural Resources and Environment needs to invest in research and investigation of the scale and distribution of the cave system; detailed 1:25,000 scale mapping of the cave structure. On that basis, propose solutions for conservation and sustainable exploitation of geological heritage, contributing to socio-economic development of the locality and region.

In fact, exploiting geological heritage to develop tourism many localities have been doing. For example, Dong Van rock plateau (Ha Giang), Dak Nong Geopark (Dak Nong) or Da Dia rapids (Phu Yen) ... Dong Nai can also exploit tourism from caves, craters, etc. if there are statistics, planning and plans for exploitation of geological resources.

Deputy Head of Culture - Information Office Dinh Quan district Thieu Quang Tan said that currently, volcanic caves have not been planned for tourism exploitation, but in the future, it is possible. Over the past time, there are still survey groups, groups of tourists to visit, explore, even film crews borrow caves as filming scenes, but the locality does not encourage them. To ensure the safety of pets, people and visitors, the Department advised the District People's Committee to issue a document warning the area with dangerous caves.

A representative of the Department of Water Resources, Minerals and Climate Change said that it is necessary to study, delineate and warn to avoid the risk of subsidence when carrying out construction works. It is recommended that people do not throw garbage and toxic substances into the cave, polluting the environment and disrupting the specific ecosystem inside.

According to Mr. Tran Viet Son, Director of Dong Nai Museum, the museum is coordinating with a number of units specializing in geology and heritage to survey and collect information related to Bat Cave, when the criteria are met, the competent authority will be requested to consider and recognize the national monument.