울릉도화산섬의 스테이지4 테프라 층중에서 다양한 화강암질 암편이 발견되었다. Rb-Sr 광물아이소크론 연대가 0.12Ma, 흑운모의 K-Ar 연령이 0.19-0.36Ma, Ar/Ar 연령이 0.29Ma로 비교적 일치 연령이 얻어 ？？다. 실리카가 결핍된 화강암질 암편 (몬조나이트)의 지화학적 ...

울릉도화산섬의 스테이지4 테프라 층중에서 다양한 화강암질 암편이 발견되었다. Rb-Sr 광물아이소크론 연대가 0.12Ma, 흑운모의 K-Ar 연령이 0.19-0.36Ma, Ar/Ar 연령이 0.29Ma로 비교적 일치 연령이 얻어 ？？다. 실리카가 결핍된 화강암질 암편 (몬조나이트)의 지화학적 특징은 울릉도 알칼리화산암류와 유사하다. 몬조나이트의 Nd-Sr동위원소비의 초생치 (87Sr/86Sr=0.70454-0.71264, 143Nd/144Nd=0.512528-0.512577)는 알칼리화산암류(87Sr/86Sr=0.70466-0.70892, 143Nd/144Nd=0.512521-0.512615)와 유사하다. 몬조나이트의 높은 스트론튬초생치는 몬조나이트는 해수와 지각물질의 혼염을 받은 알칼리현무암질마그마에서 분화된 조면암질 마그마에서 형성되었음을 지시하고 있다. 방사성동위원소의 절대연령, 지화학적특성, Nd-Sr동위원소 특성은 울릉도 몬조나이트마그마는 배호분지에서 형성된 스테이지 3의 알칼리현무암질 마그마와 동일한 성인으로 해석된다.

Numerous fragments of felsic plutonic rocks (monzonites) were found in the recent (6300-9300 YBP) tephra formed by the Stage 4 eruption of the Ulleungdo volcano, an oceanic island, which consists mainly of Quaternary alkali volcanics, East Sea, South ...

Numerous fragments of felsic plutonic rocks (monzonites) were found in the recent (6300-9300 YBP) tephra formed by the Stage 4 eruption of the Ulleungdo volcano, an oceanic island, which consists mainly of Quaternary alkali volcanics, East Sea, South Korea.
The Rb-Sr mineral isochron age for the monzonites is 0.12 Ma. K-Ar biotite ages from the same monzonite samples gave relatively concordant ages of 0.19-0.36 Ma. The 40Ar/39Ar age shows very good coherency with an age of 0.29 Ma. Geochemical characteristics of the felsic plutonic rocks, which are typically silica undersaturated alkali felsic rocks (av., 12.5 wt% in K2O+Na2O), which can be classified as monzonites, are similar to those of alkali volcanics in the Ulleungdo in terms of concentrations of major, trace and REE elements. The initial Nd-Sr isotopic ratios (87Sr/86Sr=0.70454-0.71264, 143Nd/144Nd=0.512528-0.512577) of the monzonites are also comparabled with those of the alkali volcanics (87Sr/86Sr=0.70466-0.70892, 143Nd/144Nd=0.512521-0.512615) erupted during Stage 3 (0.24-0.47 Ma) Ulleungdo volcanism. The high initial 87Sr/86Sr values of the monzonites imply that seawater and crustal contaminated pre-exisited trachytic rocks may have been melted or assimilated during differenciation of the alkali basaltic magma.
The radiometric ages, geochemical characteristics and Nd-Sr isotopic signatures of the Ulleungdo monzonites strongly suggest that the felsic (monzonitic) magma was cogenetically evolved from Stage 3 alkali basaltic magma via fractionating felsic trachytic magma, formed in the back arc basin and related to the opening of the East Sea and the Japan Sea.

Numerous fragments of felsic plutonic rocks (monzonites) were found in the recent (6300-9300 YBP) tephra formed by the Stage 4 eruption of the Ulleungdo volcano, an oceanic island, which consists mainly of Quaternary alkali volcanics, East Sea, South ...

Numerous fragments of felsic plutonic rocks (monzonites) were found in the recent (6300-9300 YBP) tephra formed by the Stage 4 eruption of the Ulleungdo volcano, an oceanic island, which consists mainly of Quaternary alkali volcanics, East Sea, South Korea.
The Rb-Sr mineral isochron age for the monzonites is 0.12 Ma. K-Ar biotite ages from the same monzonite samples gave relatively concordant ages of 0.19-0.36 Ma. The 40Ar/39Ar age shows very good coherency with an age of 0.29 Ma. Geochemical characteristics of the felsic plutonic rocks, which are typically silica undersaturated alkali felsic rocks (av., 12.5 wt% in K2O+Na2O), which can be classified as monzonites, are similar to those of alkali volcanics in the Ulleungdo in terms of concentrations of major, trace and REE elements. The initial Nd-Sr isotopic ratios (87Sr/86Sr=0.70454-0.71264, 143Nd/144Nd=0.512528-0.512577) of the monzonites are also comparabled with those of the alkali volcanics (87Sr/86Sr=0.70466-0.70892, 143Nd/144Nd=0.512521-0.512615) erupted during Stage 3 (0.24-0.47 Ma) Ulleungdo volcanism. The high initial 87Sr/86Sr values of the monzonites imply that seawater and crustal contaminated pre-exisited trachytic rocks may have been melted or assimilated during differenciation of the alkali basaltic magma.
The radiometric ages, geochemical characteristics and Nd-Sr isotopic signatures of the Ulleungdo monzonites strongly suggest that the felsic (monzonitic) magma was cogenetically evolved from Stage 3 alkali basaltic magma via fractionating felsic trachytic magma, formed in the back arc basin and related to the opening of the East Sea and the Japan Sea.

울릉도 알칼리현무암질 마그마와 화강암질마그마의 기원해석연구이다. 울릉도화산섬에서 화강암질 암편이 발견되어 울릉도에서도 심성암이 형성되었음이 밝혀？？다. K-Ar, Ar-Ar, Rb-Sr 아이소크론 연대 측정에서 0.2Ma로 세계적으로도 젊은 심성암이 확인 되었다. 동해의 ...

울릉도 알칼리현무암질 마그마와 화강암질마그마의 기원해석연구이다. 울릉도화산섬에서 화강암질 암편이 발견되어 울릉도에서도 심성암이 형성되었음이 밝혀？？다. K-Ar, Ar-Ar, Rb-Sr 아이소크론 연대 측정에서 0.2Ma로 세계적으로도 젊은 심성암이 확인 되었다. 동해의 형성과 배호분지에서의 화산활동과 심성암활동과의 관계 규명에 중요한 자료가 되고 있다. 현재 국제저널에 투고 중에 있다.