Cenozoic Strike-Slip Displacement along the Yangsan Fault, Southeast Korean Peninsula

Tectonic Implication of A-type Granites across the Yangsan Fault, Gigye and Gyeongju Areas, Southeast Korean Peninsula

“…In this paper, we show that these pre-Eocene A-type granites represent parts of the same rock body based on their similar petrography and geochemistry, and that they were separated by Cenozoic movement on the Yangsan fault. This is further evidence of the displacement previously documented by Hwang et al (2004Hwang et al ( , 2007 as 21.3 km dextral slip in the southern part of the fault.…”

“…Although there are several opinions regarding the movement sense of the Yangsan fault, such as strike-slip fault (Reedman and Um, 1975;Sillitoe, 1977;Chang et al, 1983), dipslip fault (Tateiwa, 1929;Lee and Kang, 1964;Lee and Lee, 1972;Son et al, 1978), and pivotal fault (Choi et al, 1980), strike-slip movement is favored by most workers. Dextral displacement of the Yangsan fault was postulated as 100 km by correlating mining deposits (Sillitoe, 1977), 25 km (Um et al, 1983) and 35 km (Chang, 1990;Chang et al, 1990) by correlating sedimentary rocks, and 21 km by correlating granitic rocks (Hwang, 2004;Hwang, et al, 2004Hwang, et al, , 2007. In this study, we support approximately 21-22 km slip by correlating the A-type granites.…”

Timing of granitic magma mixing in the southeastern Gyeongsang Basin, Korea: SHRIMP-RG zircon data

“…However, this uniform origin of the granitic rocks requires modification because of recent studies regarding magma mixing (Kim et al 1998(Kim et al , 1999Jeen et al 2000;Jwa and Kim 2000;Kim 2001;Kim et al 2002;Hwang 2004) and the recognition of the presence of A-type granites generated in a tensional tectonic environment (Yun and Hwang 1990;Koh 1994Koh , 2001Hwang 1995;Lee et al 1995;Koh et al 1996;Kim and Kim 1997;Lee et al 1997;Lee and Hwang 1999;Hwang 2004). On the basis of a genetic relationship between the origin of the granitic rocks and the fault systems that cut them, magmatism in the Gyeongsang Basin evidently was closely related to strike-slip faulting, involving a change of the tectonic regime from compressional to tensional (Hwang 2004;Hwang et al 2007aHwang et al , 2007bHwang et al , 2008aHwang et al , 2008b. The Yucheon volcanic rocks and the Bulguksa intrusive rocks are co-magmatic, judging by the similarity of their geochemical + isotopic characteristics and ages (Kim 1986; Geological Society of Korea 1998).…”

“…On the basis of the mineral contents, textures, occurrence of MMEs and/or mafic clots, as well as field relations, the granitic rocks in the study area can be divided into five rock types in two groups; Group I consists of granodiorite, enclave-rich porphyritic granite, and enclave-poor porphyritic granite, whereas Group II consists of equigranular granite and micrographic granite (Hwang 2004;Hwang et al 2004Hwang et al , 2007a. Group I rocks display various contents of the MMEs and/or mafic clots, implying magma mixing, whereas the Group II rocks intruding Group I lack such mafic rocks.…”

“…Late Cretaceous granitic rocks in the Gyeongsang Basin, southeastern Korean Peninsula, are considered to have undergone magma mixing by the injection of mafic liquid into felsic magma during the evolution of the latter (Kim et al 1998(Kim et al , 1999Jeen 1998;Jeen et al 2000;Jwa and Kim 2000;Kim 2001;Hwang 2004;Kim et al 2004Kim et al , 2005Hwang et al 2007a). As a result, these hybrid granites contain abundant MMEs of various aspects.…”