Abstract

Abstract. The sediment supply to the central Yellow Sea since the last deglaciation was uncovered through clay mineralogy and geochemical analysis of core 11YS-PCL14 in the Central Yellow Sea Mud (CYSM). The core can be divided into four units based on the various proxies, such as grain size, clay mineralogy, geochemistry, and Sr and Nd isotopes: Unit 4 (700–520 cm; 15.5–14.8 ka), Unit 3 (520–310 cm; 14.8–12.8 ka), Unit 2 (310–130 cm; 12.8–8.8 ka), and Unit 1 (130–0 cm; <8.8 ka). Unit 2 is subdivided into two subunits, Unit 2-2 (310–210 cm; 12.8–10.5 ka) and Unit 2-1 (210–130 cm; 10.5–8.8 ka), according to smectite content. Comparison of the clay mineral compositions, rare earth elements, and εNd indicate distinct provenance shifts in core 11YS-PCL14. Moreover, the integration of clay mineralogical and geochemical indices show different origins according to particle size. During the late last deglaciation (Units 3 and 4, 15.5–12.8 ka), Unit 4 sediments originated from all potential provenance rivers, such as the Huanghe, Changjiang, and western Korean rivers, while the source of coarse sediments changed to the Huanghe beginning with Unit 3. Fine-grained sediment was still supplied from all rivers during the deposition of Unit 3. Early Holocene (Unit 2) sediments were characterized by oscillating grain size, clay minerals, and moderate εNd values. In this period, the dominant fine-sediment provenance changed from the Huanghe to the Changjiang, whereas coarse sediments most likely originated from western Korean rivers. The Unit 1 CYSM sediments were sourced primarily from the Changjiang, along with minor contributions from the western Korean rivers. Possible transport mechanisms concerning such changes in the sediment provenance include paleo-river pathways, tidal stress evolution, and the development of the Yellow Sea Warm Current and coastal circulation systems, depending on the sea level fluctuations.

Highlights

  • The Yellow Sea, located between the China and Korean Peninsula, is a semi-enclosed epicontinental shelf with a complex oceanic circulation system (Fig. 1)

  • Most riverine sediments are trapped in estuaries and along coastal areas, some are deposited on adjacent shelves (Milliman et al, 1985, 1987), forming several shelf mud patch depositions such as Central Yellow Sea Mud (CYSM), Southeastern Yellow Sea Mud, and Southwestern Jeju Island Mud (Fig. 1)

  • Unit 2 could be subdivided into Unit 2-2 (310–210 cm; 12.8–10.5 ka) and Unit 2-1 (210–130 cm; 10.5–8.8 ka) based on the variation trends of clay mineral compositions, especially smectite content

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Summary

Introduction

The Yellow Sea, located between the China and Korean Peninsula, is a semi-enclosed epicontinental shelf with a complex oceanic circulation system (Fig. 1). Most riverine sediments are trapped in estuaries and along coastal areas, some are deposited on adjacent shelves (Milliman et al, 1985, 1987), forming several shelf mud patch depositions such as Central Yellow Sea Mud (CYSM), Southeastern Yellow Sea Mud, and Southwestern Jeju Island Mud (Fig. 1) These deposits provide abundant information on paleo-environmental changes, sediment supply, marine hydrodynamics, and climate variation (e.g., Wang et al, 1999; Kim and Kucera, 2000; Li et al, 2014a; Cho et al, 2015; Kwak et al, 2016; Hu et al, 2018). Other studies have used mineralogical, geochemical, and magnetic observations

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