• The Journal of the Petrological Society of Korea
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• v.18 no.3
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• pp.181-194
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• 2009

The Cheongryangsan Formation was reported to stratigraphically overlie the Gasongdong Formation and underlie the Dogyedong Formation in the northern part of the Yeongyang subbasin, and be divided into the lower Cheongryangsan Member and the Osipbong Member. But the members have more widely called as the Cheongryangsan Conglomerate and the Osipbong Basalt, because the latter have initially meant that thin basalt flows several times intercalate sedimentary rocks in the northern part but later must consider that they have a very dominant volume in the eastern one. Both formations are based on classifying the stratigraphy and play a role of an excellent key bed for stratigraphic correlation between local spaces in the subbasin dominant absolutely for reddish beds. Both formations play a role of excellent key bed in the northern and northwestern areas of the subbasin; the Osipbong Basalt, the midwestern, eastern and southern ones; the Cheongryangsan Conglomerate, the southeastern one.

• The Journal of the Petrological Society of Korea
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• v.26 no.3
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• pp.167-181
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• 2017

Cheongryangsan area ($49.51km^2$) has been designated as the Provincial Park in 1982, because it has magnificent aspect and seasonally spectacular landscapes. Especially, Cheongryangsa sitey ($4.09km^2$) has been designated as Noted Scenery No. 23 in 2007, because it has the same topographical landscape as rock cliffs, rock peaks and caves. The most spectacular landscapes are exhibited in the Cheongryangsan Conglomerate and Osipbong Basalt. There are twelve rock peaks on the ridges of the two strata, and many rock cliffs in the several valleys of strata, in which a few caves are formed by differential weathering and erosion. The valleys, in which flow Cheongryang, Bukgok and Cheonae streams, are classified as fault valleys along WNW-ESE faults. The rock cliffs were generated from vertical joints parallel to WNW-ESE faults in the two strata, and the caves were formed by differential weathering and erosion along bedding of sandstones and shales intercalated in the conglomerates. The rock peaks are landscapes formed by differential erosion along crossed vertical joints in the ridges. The vertical joints are developed subparallel to two WNW-ESE faults and a NNE-WWS fault. Therefore the topographical features are caused by existence of the faults and Lithologic difference in the Cheongryangsan Conglomerate and Osipbong Basalt, and by differential weathering and erosion along them.