Cretaceous to Early Tertiary Granites and Magma Mixing in South Korea : Their Spatio-temporal Variations and Tectonic Implications (Multiple Slab Window Model)

Abstract

Based on the petrologic and age data of the Cretaceous to early Tertiary granites in south Korea, we propose a new tectonic model reflecting their temporal and spatial variations. A number of petrographic and geochemical studies on the granites suggest that they originated from the magma formed by subduction of oceanic crust in continental margin and were emplaced in epizone. The MMEs with various shapes and sizes, which were produced due to the magma mixing caused by the injection of mafic magma from mantle during the crystallization of the granitic magma, are observed in the granites. The distributions of the MMEs and ages of the granites show a distinctive spatio-temporal distribution pattern. The distribution pattern can be explained by a multiple slab window model related to the ridge subduction of Izanagi-Pacific plates during the Late Cretaceous.

Magnetic fabric (anisotropy of magnetic susceptibility) constraints on emplacement mechanism of clastic dikes

“…The succession has been divided into three major lithostratigraphic units according to their occurrence and the relative amounts of volcanic versus nonvolcanic deposits [ Chang , ; Choi , ; Chough and Sohn , ]: the Sindong Group consisting mostly of nonvolcanic sedimentary strata, the Hayang Group containing partly volcanic strata, and the Yucheon Group comprising dominantly volcanic strata in ascending order. All these strata were intruded later by a set of the plutonic rocks named the Bulguksa Granite [ Jin , , ; Hong , ; Hwang et al , ; Cho et al , ; Kim et al , , ]. Chough and Sohn [] interpreted that the basin belonged to a Cretaceous arc system comprising an arc platform composed of the volcanic rocks of the Yucheon Group and a back‐arc basin filled by the sedimentary strata of the Sindong and Hayang Groups.…”

Field Evidence of Magma Mixing from Concentric Zoning and Mafic Microgranular Enclaves in Bunam Stock, Korea

“…Vernon, 1984;Didier and Barbarin, 1991). 최근에 많은 연구에서 고철질 미립상 포유체(mafic microgranular enclave, MME)를 포함하는 화강암질암 (granitoid)은 조성이 서로 다른 두 마그마의 혼합작용 에 의한 결과라고 보고되었다 (Reid et al, 1983;Zorpi et al, 1989;Didier and Barbarin., 1991;Holden et al, 1991;Jwa and Kim, 2000;Kim et al, 2004Kim et al, , 2012Kim et al, 2005).…”

SHRIMP U-Pb Zircon Ages of the Gusandong (Kusandong) Tuff in the Cretaceous Gyeongsang Basin

“…1b), 대부분 충적에서 호성 퇴적환경에서 퇴적된 것으로 알려져 있다 (Choi, 1986;Rhee et al, 1998;Jo and Chough, 2001;Houck and Lockley, 2006;Paik and Kim, 2006). 한편, 분지의 남동부에 주로 분포하는 유천층군과 이를 관입하고 있는 불국사화강암류에 대한 암석학적 연구들은 이들 화성암의 기원이 화산호 환경과 밀접히 관련되어 있 음을 보고하고 있다 (Min et al, 1982;Yun, 1988Yun, , 1998Kim et al, 1991;Kim and Lee, 1993;Hwang and Kim, 1994;Sung et al, 1999;Kim et al, 2012). (Fig.…”