Abstract The environmental evolution and provenance of the sediments since 1.2 Ma penetrated by the borehole of JXC-1 in Northwestern Liaodong Bay are studied in this paper using the data from accelerator mass spectrometry 14C dating, optically-stimulated luminescence dating, paleomagnetic dating, qualitative and quantitative analysis of benthic foraminifera, and the geochemistry analysis. Based on regional stratigraphic correlation, the evolution of sedimentary environment and provenance are discussed. The study suggests that large-scale transgression began by the end of Middle Pleistocene, and invaded into this region for three times from Late Middle Pleistocene to Holocene, in MIS 7, MIS5, and MIS1, that is in consistent with the global pattern of sea level changes. The results of this study are different from previous researches in the Bohai Sea, which found three times of transgressions in MIS5, MIS3, and MIS1 respectively. There are two possibilities, either no transgression in the Bohai Sea, or the transgression did not enter Liaodong Bay during the time of MIS3. Provenance analysis shows that the northwest of Liaodong Bay is a mixed depositional area. Sediments are mainly sourced from the Yellow River, Liaohe River (formerly Shuangtaizi River) and Daliao River. During the three marine phases, the sediments of the JXC-1 borehole came mainly from the Yellow River characterized by high content of CaO, and deposited under the control of Bohai Sea circulation and coastal currents. The sediments in depths of 36.00–46.00 m and 58.20–70.30 m of the borehole are high water level lacustrine sediments, mainly came from the Yellow River. However, the sediments in depths of 46.00–58.20 m are mainly brought in by the Liaohe and Daliao rivers. All these studies suggest that the sediments coming from the Yellow River may be distributed northward up to 40.5°N. As a major conclusion different from previous understandings, this paper provides an important reference for the evolution of the sedimentary environment and the provenance of the Late Quaternary deposits of the Bohai Sea.

中文翻译：

---

辽东湾西北部中更新世沉积环境演化及物源分析

摘要 本文利用加速器质谱14C测年、光致发光测年、古磁测年、定性和定性测年数据，研究了辽东湾西北部JXC-1钻孔1.2 Ma以来沉积物的环境演化和物源。底栖有孔虫定量分析和地球化学分析。在区域地层对比的基础上，讨论了沉积环境和物源的演化。研究表明，大规模海侵开始于中更新世末期，中更新世晚期至全新世在MIS 7、MIS5和MIS1期间3次侵入该地区，与全球海相格局一致。水平变化。本次研究的结果与以往在渤海的研究结果不同，此前渤海研究分别在MIS5、MIS3和MIS1中发现了3次海侵。有两种可能，要么渤海没有海侵，要么海侵在MIS3时期没有进入辽东湾。物源分析表明，辽东湾西北部为混合沉积区。沉积物主要来源于黄河、辽河（原双台子河）和大辽河。在三个海相期间，JXC-1钻孔沉积物主要来自黄河，以CaO含量高为特征，在渤海环流和沿岸流的控制下沉积。钻孔深度36.00-46.00 m和58.20-70.30 m的沉积物为高水位湖相沉积物，主要来自黄河。但46.00～58.20 m深度的沉积物主要由辽河和大辽河带入。所有这些研究表明，来自黄河的沉积物可能向北分布达 40.5°N。作为不同于以往认识的重大结论，本文为渤海晚第四纪沉积环境演化和物源研究提供了重要参考。