现代黄河三角洲YRD-1401孔MIS 5以来沉积层序及其古环境意义

近年来渤海地区晚更新世以来沉积环境演化和地层划分存在争议。本文对现代黄河三角洲东南海岸带YRD-1401孔岩芯（长81.00 m）沉积物进行综合研究，旨在建立该孔晚更新世以来地层的沉积相序列和时间标尺，为解决地层划分争议提供新的证据。根据AMS ¹⁴C和光释光测年结果，并考虑到YRD-1401孔底部地层光释光年代的不精确性，本文主要研究YRD-1401孔MIS 5以来的沉积演化史。综合分析YRD-1401孔沉积地层的岩性特征和底栖有孔虫组合变化，结合测年结果，该孔可划分为6个沉积单元（从下往上DU 6~DU 1）：最底部的DU 6（51.35~81.00 m）为受潮流影响的河流沉积（其形成时间有待进一步研究），DU 5（37.64~51.35 m）为MIS 5潮坪-近岸浅海沉积，DU 4（30.71~37.64 m）为MIS 3早期的潮坪沉积，DU 3（23.50~30.71 m）为MIS 3晚期至全新世早期形成的河流沉积，DU 2（14.22~23.50 m）为全新世早期（约10 cal.ka B.P.）至1855年形成的滨岸沼泽-滨岸浅水-近岸浅海~前三角洲沉积-海洋改造层，DU 1（0~14.22 m）为1855年以来发育的现代黄河三角洲沉积。晚更新世以来该孔有3个海相层（自下而上分别是DU 5、DU 4和DU 2），分别形成于MIS 5、MIS 3早期和全新世，表明晚更新世以来全球海平面变化是其主要控制因素。研究区MIS 4的沉积地层出现缺失。渤海沿岸地区多个钻孔地层的对比表明，区域性的差异构造沉降、沉积物供给和地层完整性等因素也是影响研究区晚更新世以来沉积地层发育的重要因素。

The sedimentary succession of core YRD-1401 in the modern Yellow River Delta since MIS 5 and its paleoenvironmental significance

Dramatical changes in sea level and the associated sea-land interactions are known to have occurred in the Bohai Sea during the Quaternary. There has been a debate on the ages of the latest three marine strata in the Bohai Sea during the Late Quaternary. Although the recent development in Optical Stimulated Luminescence(OSL) dating has led to great improvement in the precision of chronology, the environmental evolutions and division of sedimentary strata in the Bohai Sea have been open to debate since the Late Pleistocene. In this study, the sedimentary succession and chronological framework of core YRD-1401 were established based on the analyses of sediment grain size, benthic foraminiferal assemblages, accelerator mass spectrometry(AMS) 14C and OSL datings, with a view to offering new insights into the division of sedimentary strata.