Economic and Environmental Geology (자원환경지질)
- Volume 16 Issue 1
- /
- Pages.19-36
- /
- 1983
- /
- 1225-7281(pISSN)
- /
- 2288-7962(eISSN)
Petrology of Alkali Volcanic Rocks in Northern part of Ulrung Island
울릉도(鬱陵島) 북부(北部) 알칼리 화산암류(火山岩類)에 대(對)한 암석학적(岩石學的) 연구(硏究)
- Kim, Yoon Kyu (Department of Geology, Yonsei University Seoul) ;
- Lee, Dai Sung (Department of Geology, Yonsei University Seoul)
- Published : 1983.03.31
Abstract
The study revealed that the sequence of volcanism in Ulrung island can be classified into 5 stages, and the volcanic history is summerized as follow: 1st stage: Eruption of basaltic agglomerates, tuffs and lavas, 2nd stage: Eruption of trachytic and trachyandesitic agglomerates and tuffs, 3rd stage: Eruption of trachyte lavas and their lapilli tuffs, 4th stage: Eruption of trachyte lavas and nepheline phonolites, 5th stage: Eruption of pumice, trachytic ash and lapilli, and plutonic ejecta (fragments of alkali gabbro, monzonite and alkali feldspar syenite) and a subsequent caldera formation. Finally, a small scale eruption of leucite bearing trachyandesite lava in the caldera. Several evidences show that there have been long erosional intervals between the 1st and 2nd stages and between the 4th and 5th stages. A K-Ar age for trachybasalt lava of the 1st stage was determined to be 1.8 Ma, and a
Keywords