Palaeoceanography of the Japan Sea Across the Mid‐Pleistocene Transition: Insights From IODP Exp. 346, Site U1427

Abstract

Introduction The Mid-Pleistocene Transition and the East Asian MonsoonThe Quaternary period is characterized by glacial-interglacial variability that has been linked to Earth's orbital cyclicity (e.g., Hays et al., 1976;Ruddiman, 2001). During the early part of the Quaternary, glacial-interglacial cycles varied at a frequency of 41,000 years (41 ka), but approximately half-way through the Quaternary, during the mid-Pleistocene, the glacial-interglacial cyclicity shifted to quasi 100,000 years (100 ka) cycles (e.g., Lisiecki & Raymo, 2005;Zachos et al., 2001). The transition period between 41 ka and 100 ka is centred at ∼1200 to 600 ka and often referred to as the mid-Pleistocene transition (MPT). After the MPT, glacials became more intense, producing larger ice-sheets that decayed more rapidly at glacial terminations (e.g.

Sediment depositional pattern in the northern Japan Sea over the last 1200 ka and its linkages to orbital forcing

“…Anoxic conditions are not strong and frequent between 1200 and 900 ka, and thereafter they occur periodically (Figure 6). Felder et al (2022) suggested that the Japan Sea had higher δ 18 O values during these periods of early middle Pleistocene transition (MPT) as the glacial conditions were severe. During this period sediment is characterized by high silt (>80%), high SS (%), high quartz and moderately sorted, (aeolian sediment characteristics) and the depositional environment is mainly affected by EAWM, westerly wind and minor riverine and IRD.…”

“…Sediment records from marginal environments like the Japan Sea are challenging to analyse due to various factors, such as the palaeoceanographic reactions to climate change and the presence of terrestrial and marine signals (Tada et al, 1999). The Japan Sea responds to orbital to regional-scale climatic change and may be significantly more sensitive than the open oceans (Das et al, 2018(Das et al, , 2021Felder et al, 2022;Gallagher et al, 2018;Huang et al, 2018;Tada, 2004;Tada et al, 1999).…”

“…Sediment records from marginal environments like the Japan Sea are challenging to analyse due to various factors, such as the palaeoceanographic reactions to climate change and the presence of terrestrial and marine signals (Tada et al, 1999). The Japan Sea responds to orbital to regional‐scale climatic change and may be significantly more sensitive than the open oceans (Das et al, 2018, 2021; Felder et al, 2022; Gallagher et al, 2018; Huang et al, 2018; Sagawa et al, 2018; Tada, 2004; Tada et al, 1999). The semi‐enclosed peripheral Japan Sea is known to be impacted by global sea‐level oscillations, seasonal and permanent ice cover expansion and orbital scale variability and these reactions are retained in the ocean bottom sediment record.…”

Geochemistry of Foraminifera in the Marginal Seas of the Sunda Shelf: A Review

“…The waxing and waning of the ice will influence the oxygen isotopes, and the isotopic ratio changes indicating the foraminifera will record the sea level. Mg/Ca ratios will then discriminate the local freshwater effect from the global ice volume signal (Felder et al, 2022).…”