Genetic Relationship and Structural Characteristics of the Fe-Ti Ore Body and the Sancheong Anorthosite, Korea

Abstract

It consists of the Precambrian Jirisan metamorphic complex and Sancheong anorthosite complex and the Mesozoic granitoids which intrude them in the Sancheong area, the Jirisan province of Yeongnam massif, Korea. The study area is located in the western part of the stock-type Sancheong anorthosite complex. We performed a detailed fieldwork on the Sancheong anorthosite (SA) and Fe-Ti ore body (FTO) which constitute the Sancheong anorthosite complex, and reinterpreted the origin of FTO foliation and the genetic relationship between them from the foliations, shear zones, occurrences of the SA and FTO. The new structural characteristics between them are as follows: the multilayer structures of FTO, the derived veins of straight, anastomosing uneven types and block structures related to the size reduction of SA, the gradual or irregular boundaries of SA blocks and FTO showing bulbous lobate margins and comb structures, the FTO foliation and linear arrangements of flow occurrence which is not ductile shear deformation, the discontinuous shear zone of SA, the orientation of FTO foliations parallel to the boundaries of SA blocks, the predominance of FTO foliations toward the boundaries of SA blocks and being proportional to the aspect ratio of plagioclase xenocrysts and SA xenoblocks, and the flow folding structures of FTO foliation. Such field evidences indicate that the SA is not fully congealed when the FTO is melt and the fracturing of partly congealed SA causes the derived veins of FTO and the size reduction of SA. Also the gradual or irregular boundaries of SA blocks and FTO result from the mutual reaction between the not fully congealed SA blocks and the FTO melt, and the FTO foliation is a magmatic foliation which was formed by the interaction between the FTO melt and the partly congealed SA blocks. Therefore, these suggest that the SA and FTO are not formed from the intrusion of different magmas in genesis and age but from a coeval and cogenetic magma through multiple fractionation. We predict that the FTO will show an very irregular occurrence injected along irregular fractures, not the regular occurrence like as the intrusive vein and dike. It can be applied to the designing of Fe-Ti mineral resource exploration in this area.

Geometric and Kinematic Characteristics of Fracture System in the Sancheong Anorthosite Complex, Korea

“…그러나 고생대 말 이후 에 취성변형작용과 관련된 연구는 거의 수행된 바가 없다 Kim et al, 2010 Lee and Kang, 2012 (Kang and Lee, 2014).…”

Formation Process and Its Mechanism of the Sancheong Anorthosite Complex, Korea

“…B: Bonghwa, G: Gwangju, Ga: Gangneung, Gc: Geochang, Gi: Gimcheon, Hd: Hadong, Hy: Hamyang, J: Jeomchon, Je: Jeonju, Jj: Jinju, Jn: Jinan, Mo: Mokpo, Mt.J: Jirisan, Mt.S: Sobaeksan, Nw: Namweon S: Sunchang, Sc: Sancheong, Se: Seoul, Su: Subi, W: Wando, Y: Yecheon, Ye: Yeongkwang. Kang and Lee, 2014). (b) Simplified geological map of the Sancheong anorthosite complex showing stock type and its surrounding area with the locality of study area (after Kang and Lee, 2014).…”

“…Kang and Lee, 2014). (b) Simplified geological map of the Sancheong anorthosite complex showing stock type and its surrounding area with the locality of study area (after Kang and Lee, 2014). (c) Simplified geological map of the study area with the sites and numbers of SA, FTO, MG outcrops.…”

“…2c). 연구지역의 산청 회장암체는 SA, FTO, MG로 구분 되고(Kim et al, 2011;Kang and Lee, 2014), SA 는 괴상형과 엽상형으로 세분된다(Kang and Lee, 2014). 괴상형 SA는 주로 소량의 유색광물과 함께 중 립과 조립의 사장석으로 구성되어 있으며, 엽리의 발 달이 없다(Fig.…”

“…3b). FTO는 주로 각섬석과 티탄철석으로 구성된 다량의 유색광물 집합체와 소량의 거정 사장석과 SA 블록으 로 구성되어 있으며, 구성광물과 산상은 간극누적형 SA(Jeong et al, 1989;Lee et al, 1999)와 유사하 다(Fig.3c, 3d)(Kang and Lee, 2014). FTO 엽리는 거정의 사장석과 SA 블록 그리고 이들 사이를 메우는 유색광물 집합체의 정향배열에 의해 정의된다.…”