제주도 동부 알칼리 현무암내 스피넬-레졸라이트 포획체의 연구

• 발행기관: 대한자원환경지질학회
• 저자명: 윤성효 고정선 안지영
• 간행물 정보: 『자원환경지질』31권 5호, 447~458쪽, 전체 12쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1998.10.30

영문 초록

The spinel lherzolite of ultramafic xenoliths are found in the alkali basalt from eastern part of the Cehju island, Korea. The xenolith is are mainly composed of olivine, orthopyroxene, clinopyroxene and spinel. Based on the chemical conmpositions of the constituent minerals, the ultramafic xenolith belong to upper mantle peridotite. Each minerals have a protogranular texture. Olivine with kink band texture partly shows undulatory extinction. Some clinopyroxenes have spongy textured rims. Brown spinels occur in the interstices between olivine and pyroxene grains. Olivine is mostly forsterits (Fo89.90). Orthopyroxene is enstatite (Wo1.3En88.4Fs10.3) with 3.87∼5.25 wt% Al₂O₃. Clinopyroxenes is diopside (Wo48.0En46.2Fs5.8) with 6.75∼5.03 wt% Al₂O₃. Spinel has the Mg value of 75.9 and its cr-number is 10.2. According to the P-T estimations for the mantle xenoliths, equilibrium temperatures of the xenoliths range from 1023 to 1038℃ and pressure is 18 kbar, Spinel lherzolith from this area, which is characterized by lower Cr-number (10.2) and homogeneous chemical compositions, supports that these ultramafic xenoliths are derived from the upper mantle.

키워드

상부맨틀 킴벌라이트 알칼리현무암 초염기성포획암 제주도 지그리오름 신산리 온평리용암