The study on the Igneous Activity in the Southeastern Zone(SE-zone) of the Ogcheon Geosynclinal Belt,Korea(III) (with the Igneous Activity between Naju and Namchang Area)

옥천지향사대(沃川地向斜帶) 동남대(東南帶)에서의 화성활동(火成活動)(III)(나주(羅州)-남창지역(南倉地域)을 중심(中心)으로)

  • Received : 1991.07.12
  • Published : 1991.06.30

Abstract

The main aspect of this study are to clarify igneous activity of igneous rocks, which is a member of various intrusives and volcanics exposed in Naju-Namchang area of southern central zone of Ogcheon Geosynclinal Belt, southern part of Youngdong-Kwangju depression zone of tectonic provinces in Korea. Naju-Namchang area are subdivided into three rock belts based on occuring of Cretaceous granites. Three rock belts consist of foliated granites, Jurassic granites and Cretaceous granites in central granitic rock belt (C-C), and acidic tuff and lavas in northwest volcanic rock belt(C-NW) and southeast volcanic rock belt(C-SE). Chemical composition of these igneous rocks show mostly similar trend to the Daly's values on Harker diagram and correspond to VAG + Syn-COLG region on Pearce's discrimination diagram. These igneous rocks vary wide range in total REE amount(37.4-221.3ppm) characterized by enriched LREE content and steep negative slope in Eu(-) anomaly. It is concluded each synchronous granites which composed of serveral rock facies is considered to formed by differentiation of co-magma at continental margin, and igneous activity of study area are two more Pre-Cambrian Orogenies, Songrim Disturbance, Daebo Orogeny and Bulkuksa Disturbance.

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