Ragac

2

This geosite is open for the public.

History and value

Ragács (slag cone with lava flow): one of the most significant volcanic structures in the Cseres Mountains. The high peak at 470 meters above sea level is formed by a slag cone with aggregated bombs, slag and lava fragments. In places, they alternate with perforated layers of lava with a southward slope. Volcanic bombs and shards are also perforated, testifying to the high gas content of the lava and the explosive nature of volcanism. This has already been stated by L. Jugovics (1944), who also mentions an exhalation chimney and cavities from here. A few basalt valleys were also pushed into the slag cone, which more or less prepared out of the surrounding tuff. One of them forms one peak and the other rises 1-2 meters wide and 17 meters high on the northwest slope. From the Ragács volcano, a 3 km long lava flow flowed to the surface in the southern direction. Above each other, two lava flows can be distinguished, which are indicated by a 10-15 meters high jump on the surface.The bombs in the ragács quarry suggest that these are remnants of the older tuff ring of the older Békástó crater, so the lava flow ran around it, perhaps in part its own crater wall (Gaál 1999, but Konečný et al. 2004 assumes the original crater north of the current peak). The predominantly bench-separated basalt of the lava flood is excavated by several quarries. The radiometric age of basalt is 1.39 ± 0.19 million years (Balogh, Mihaliková, & Vass 1981).

The Ajnácskő - Várgede hiking trail leads to the site.Degree of protection: 5, National Natural Monument. Part of a natural area of European importance Cseres Mountains - forest biotopes.

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