Distinctive Two Stage Syn-Rift Activities of the Backarc Ulleung Basin, Korea, and Implications for New Plays
KyoungA, Lee; Woo, Byungkwon; Park, Bitna; Huh, Sunggeun; Roh, Eul; Choi, Byeonggoo
The backarc Ulleung Basin developed along the western margins of the Pacific Plate between Korea Peninsula and Japan Island, had recorded various consequences caused by subduction of the Plate and reactivations during the Cenozoic. Evaluation of two stage syn-rift sediments using two & three dimensional seismic data and outcrops revealed genetic relationships and tectonic evolutions of small basins which mainly consisted of fan deltas and marine depositions around the Basin, onshore and offshore Korea. The first stage syn-rifting was characterized as backarc extensions caused by normal faulting. A few fan delta sediments with the normal faults were observed around the Basin margins. Subsidence due to crustal thinning dominated during the second stage syn-rifting and caused the regional marine invasions which generated northwestward shelf break moving. Submarine fans developed during the second stage were classified as potential reservoirs of new plays with favorable petroleum systems different from the first stage. This study revealed that normal faulting and crust thinning were sequential reactivations induced by subduction of the Plate, tectonics mainly controlled depositional environments through the syn-rift activities of the Basin, and the second stage syn-rift sediments were evaluated as new plays.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013