백악기 및 제 3기 퇴적층에 발달된 연질퇴적변형구조: 산상 및 기원

Abstract

The soft-sediment deformation structures were studied in the Cretaceous (Jinju and Seongpori Formation) and Tertiary (Eoil and Hagjeon Formation) deposits in Korea. The soft-sediment deformation structures mainly occur in the facies of interlaminated to interbedded fine- to medium- grained sandstone and mudstone, and they are classified into the slump and convolute structures, water-escape structures, syndepositional faults, clastic dykes, and rip-down clasts on the basis of their morphological occurrences. These are interpreted to have been formed in the unlithified state due to liquefaction and/or fluidization. Suite of soft-sediment deformation structures is considered to be secondary evidence of synsedimentary paleo-earthquake (seismite). This study shows new evidence of tectonic activity and paleo-environment when the earthquakes took place.