Evolution of the Late Cretaceous Dadaepo Basin, SE Korea, in response to oblique subduction of the proto-Pacific (Izanagi/Kula) or Pacific plate

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

“…Third, the tectonic setting of the Dadaepo Basin also supports the seismically triggered fluidization. The basin is interpreted to be a pull‐apart basin extended by strike‐slip faulting of the two NNE trending border faults [ Son et al , ; Cho et al , , ], indicating that many earthquakes occurred during the deposition of the Lower Dadaepo Formation. In the strike‐slip basins along the San Andreas Fault System, similar clastic intrusions have been recognized at many places [ Newsom , ; Thompson et al , ].…”

“…The basin is thus interpreted as an isolated intra‐arc basin in the Gyeongsang arc platform [ Chough and Sohn , ]. Recently, detailed structural analyses suggest that the basin is a pull‐apart basin extended by the sinistral strike slip of the Yangsan and Dongnae Faults due to the oblique northward subduction of the proto‐Pacific or Pacific plate beneath the Asian continent [ Son et al , ; Cho et al , , ].…”

“…The Korean Peninsula, located on the eastern margin of the Asian continent, is an important tectonic link between eastern China and the Japanese Arc (Figure a). In the Cretaceous, the peninsula was located behind the magmatic arc due to subduction of the proto‐Pacific (Izanagi) plate beneath the Asian continent, forming a number of nonmarine basins [ Chough et al , ; Chough and Sohn , ; Cho et al , ]. The largest Gyeongsang Basin (Figure b) was filled by a thick succession of nonmarine sedimentary rocks and diverse volcanic deposits [ Chang , , ; Chough et al , ].…”

“…TR: Triassic Granites, SG: Sindong Group, HG: Hayang Group, YG: Yucheon Group, BG: Bulguksa Granites, and MR: Miocene Rocks. (c) Geological map of the Dadaepo Basin [ Cho et al , , ] with outcrop localities of the clastic dikes and sampling sites.…”

“…A lot of neptunian and injected clastic dikes and associated seismites are observed in the Late Cretaceous Dadaepo Basin, SE Korea, which is interpreted as a small intra‐arc basin within the Cretaceous Gyeongsang Arc System [ Chough and Sohn , ; Cho et al , ] (Figure ). We carried out a series of analysis to retrieve the rock fabrics of the clastic dikes and the surrounding host rocks using the AMS technique and to identify their magnetic carriers.…”