Geology of Danyang

A Week in Danyang (2)

Korea is rich in limestone, and the area near Danyang is a typical limestone-rich area. Limestone-rich areas develop karst terrain. Limestone is mainly composed of calcite, which is composed of calcium carbonate (CaCO3), so when it comes into contact with water, it easily dissolves through a reaction such as CaCO3 + H2O + CO2 = Ca(HCO3)2. This is because water and carbon dioxide, on the left, change it into a water-soluble component. Karst terrain is characterized by limestone formations, such as limestone caves and dolines (sinkholes). The Kras region, where Slovenia meets Italy, is a representative limestone region in Europe, and geological studies of the region have led to the term karst.

Gosu Cave and Ondal Cave

Gosu Cave is located in Gosu-ri, Danyang-eup, Danyang-gun. The cave is located about 5-10 minutes after crossing the Namhan River along the Goji-dae Bridge in front of the terminal in Danyang-eup. Gosu Cave is the most famous natural cave in Korea and was designated as Natural Monument No. 256 in 1976. According to researchers, the cave was formed from limestone layers in the early Paleozoic Era and took about 450 million years to form.

At the end of the cave, there is an introduction to Park Changwon. Paraphrasing:

With the great intention of evangelizing the school and fostering human resources that God is pleased with, Dr. Changwon Park founded Yusin Academy in 1976 to develop Goji Cave as a natural learning center and to return corporate profits to the society. To honor the founder's noble spirit of cultivating talented people who love and serve their country and their fellow man based on the Christian spirit of faith, hope, and love, a monument is erected here.

Next to it is a somewhat out-of-place pagoda. It's not authentic, it's a copy of a pagoda in Hwaeumsa Temple in Guryeo, and it seems to be trying to tell a story about Silla, but there's a pagoda that I don't understand, which is supposed to commemorate the last frontier of General Ondal, the longest-serving general of Goguryeo -- I'm not sure what that means. This is also about Park Changwon.

Anyway, to recap, Gosu Cave is a natural monument, but it was developed by Park Chang-won and is currently operated by Yusin, the same company that financially sponsors Yusin High School in Suwon. In other words, it's a privately owned facility that charges a fee to visit. On the other hand, the parking lot is a public parking lot and there are restaurants and other shops in front of it, so I wonder about the ownership relationship.

Ondal Cave is located at the beginning of the entrance to Guinsa Temple. As a resident of (former) Gwangjin-gu who knew Achasan in Gwangjin-gu as the site of Ondal, I was surprised that the story of Ondal came from Danyang. Danyang's claim is that Ondal of Goguryeo died in battle trying to retrieve Adanseong, and that Adanseong in question refers to Euladan, the old name for Yeongchun-myeon, and that the mountain in Yeongchun-myeon belonged to Goguryeo before it was lost to Silla. However, it is argued that the original Goguryeo territory is unreliable considering that by the late 6th century, when Ondal died, Silla had already advanced north of the Han River, and that the current Ondal Mountain Castle is very similar to Silla's construction.

However, there is no conclusive evidence that Achasanseong in Gwangjin-gu was the site of Ondal's final battle. As is often the case in ancient history, there is a lack of conclusive written or archaeological evidence. But what I found interesting is that in this situation, Danyang is marketing Ondal. They are utilizing Ondal Mountain Castle, which is designated as a historical site, to build a drama filming site and place Ondal Cave at the end of it, and they are earning income from viewing fees for Ondal Cave. Considering that there are not many people who would come to Ondal Cave alone due to its location, Dan Yangkwon's decision to allow Ondal Cave to generate income from tourist fees is reasonable. However, until the area where General Ondal died can be scientifically proven.

National Geopark

Danyang is designated as a national geopark. National Geoparks have been designated by UNESCO in recognition of the scientific and environmental importance of geological heritage. In Korea, Jeju Island was listed as a UNESCO Geopark in 2010, and the Natural Parks Act was amended in 2011 to establish a system for listing it as a natural park. Currently, there are 15 national geoparks in Korea, of which Jeju Island, Cheongsong, Musan Mountain Area, and Hantan River have been recognized by UNESCO.

Danyang National Geopark has 12 geological sites: Seonam Valley, Samtae Mountain Scenery, Doosan Airstrip, Dodamsam Peak, Gudam Peak, Gosori Coriander Cave, Ondal Cave, Labor Cave, Daryan Soft Shear Zone, Sineam, Mancheonha Scenery, and Yeocheon-ri Doline Group. As u can see from this list, most of the places we call "scenic" in Danyang are geologically significant and worthy of preservation and research.

Limestone, the raw material for cement

If you go a little further past the area where the public facilities are located in Danyang Town and head towards Dodamsambong Peak, you will come to the Seongsinsinyanghoe Temple. Seongsin Yanghoe is a publicly traded company that was founded in 1967 as a manufacturer of Cheonma Marked Cement. It was a large company until 2020 and was downgraded to a medium-sized company in 2020. For about a decade, its sales were around 700 billion won, but since last year, its sales have exceeded 1 trillion won.

The factory in Danyang is the core plant of Sungshinyang Cement. If you go a little further up the road from the town center past Dodamsambong Mountain, you will see a huge factory reminiscent of Mad Max. This is the factory of Seongsin Yanghoe. There are no roads surrounding the building, so it's not easy for the average person to guess the full scale of the factory, but if you look at a map, you can see that it's huge. This explains the seven buildings and the trucks that are so common in Danyang.

A little further on from Seongshinyanghoe is the Hanil Cement Factory. If Seongshinyanghoe was based in Danyang-eup, Hanil Cement made Maeppo-eup. In Maeppo, there is a Hanil Cement residence and dormitory. When traveling to Danyang by train from Seoul, Dodam Station, just before Danyang Station, is right next to Hanil Cement. Dodam Station is not a passenger station, but rather serves to transport cement from the factories of Hanil Cement and Seongsin Yanghoe, and there are branch lines from Dodam Station to Hanil Cement and Seongsin Yanghoe respectively. Before it was submerged, Dodam Station was located in Seongsin Yanghwa, and there were several lawsuits and administrative appeals over the new Dodam Station being moved near Hanil Cement. Convenience of transportation is very important for cement, which is expensive and heavy.

Translated with www.DeepL.com/Translator (free version)