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Pleistocene forced regressive deposits on the Korea Strait shelf influenced by tectonic and ocean currents
Geo-Marine Letters ( IF 2.1 ) Pub Date : 2019-11-19 , DOI: 10.1007/s00367-019-00613-y
Dong-Lim Choi , Yong-Kuk Lee , Dong-Hyeok Shin , Seom-Kyu Jung , Byung-Cheol Kum

We examined the architecture of Pleistocene sequences of the Korea Strait (KS) margin controlled by ocean currents and compressional tectonic regimes, using a dense grid of high-resolution single-channel seismic profiles and sediment cores. Along with uplifted strata featuring an erosional and/or non-depositional flat seabed in the northern shelf of the study area, three Middle–Upper Pleistocene sequences are characterized by forced regressive deposits recorded at 100-ka intervals covering one postglacial sequence across the shelf. The three forced regressions together comprise an offlapping stacking pattern, where the degree of erosion of the upper surface of the older sequence is greater than that of the younger sequence. The tectonic tilt involved in landward uplift and seaward subsidence across the shelf basin causes differential erosional rates among the forced regression deposits. The Upper Pleistocene forced regression deposits are preserved as a set of 20-ka clinoform wedges with aggradational to progradational stacking patterns, leading to a falling stage systems tract (FSST) during the stepwise fall in sea level, followed by a shelf edge-perched lowstand systems tract (LST) wedge during the Last Glacial Maximum (LGM). The northeast-facing Tsushima Current (TC) passing through the KS played an important role in allowing the fine sediments originating from the Nakdong River to form the FSST clinoform wedges and the LST oblique prograding delta lobe along the shelf break.

中文翻译:

受构造和洋流影响的更新世迫使韩国海峡陆架海退沉积

我们使用高分辨率单通道地震剖面和沉积物核心的密集网格检查了由洋流和挤压构造制度控制的韩国海峡 (KS) 边缘更新世序列的结构。连同研究区北部陆架以侵蚀和/或非沉积平坦海床为特征的隆起地层,三个中上更新世序列的特征是强制回归沉积,以 100 ka 间隔记录,覆盖整个陆架的一个冰后序列。这三个强制回归共同构成了一个重叠的堆叠模式,其中旧序列上表面的侵蚀程度大于新序列上表面的侵蚀程度。横跨陆架盆地的向陆抬升和向海沉降所涉及的构造倾斜导致强制海退沉积物之间的侵蚀速率不同。上更新世强迫海退沉积物被保存为一组 20 ka 斜楔形,具有加积到进积的堆积模式,在海平面逐步下降期间导致下降阶段系统域 (FSST),随后是陆架边缘栖息的低水位末次盛冰期 (LGM) 期间的系统域 (LST) 楔形。穿过 KS 的面向东北的对马洋流 (TC) 在允许源自洛东河的细粒沉积物沿陆架断裂形成 FSST 斜陆形楔和 LST 斜进积三角洲裂片方面发挥了重要作用。上更新世强迫海退沉积物被保存为一组 20 ka 斜楔形,具有加积到进积的堆积模式,在海平面逐步下降期间导致下降阶段系统域 (FSST),然后是陆架边缘栖息的低位末次盛冰期 (LGM) 期间的系统域 (LST) 楔形。穿过 KS 的面向东北的对马洋流 (TC) 在允许源自洛东河的细粒沉积物沿陆架断裂形成 FSST 斜陆形楔和 LST 斜进积三角洲裂片方面发挥了重要作用。上更新世强迫海退沉积物被保存为一组 20 ka 斜楔形,具有加积到进积的堆积模式,在海平面逐步下降期间导致下降阶段系统域 (FSST),随后是陆架边缘栖息的低水位末次盛冰期 (LGM) 期间的系统域 (LST) 楔形。穿过 KS 的面向东北的对马洋流 (TC) 在允许源自洛东河的细粒沉积物沿陆架断裂形成 FSST 斜陆形楔和 LST 斜进积三角洲裂片方面发挥了重要作用。紧随其后的是末次盛冰期 (LGM) 期间位于陆架边缘的低位系统域 (LST) 楔。穿过 KS 的面向东北的对马洋流 (TC) 在允许源自洛东河的细粒沉积物沿陆架断裂形成 FSST 斜陆形楔和 LST 斜进积三角洲裂片方面发挥了重要作用。紧随其后的是末次盛冰期 (LGM) 期间位于陆架边缘的低位系统域 (LST) 楔。穿过 KS 的面向东北的对马洋流 (TC) 在允许源自洛东河的细粒沉积物沿陆架断裂形成 FSST 斜陆形楔和 LST 斜进积三角洲裂片方面发挥了重要作用。
更新日期:2019-11-19
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