Evidence of sea ice-driven terrigenous detritus accumulation and deep ventilation changes in the southern Okhotsk Sea during the last 180ka

Sediment provenance variations in the southern Okhotsk Sea over the last 180 ka: Evidence from light and heavy minerals

“…The dominant minerals in core OS03-1 are quartz and plagioclase, which are consistent with other mineralogical and geochemical records available from cores MD01-2414 (Liu et al, 2006), OS03-1 (Zou et al, 2015) and LV28-42-4 & LV28-44-3 (Nürnberg et al, 2011). Core sediments investigated from the eastern part of Okhotsk Sea contain higher content of hornblende compared to cores from the western part of Okhotsk Sea and was deemed as derived from the Kamchatka Peninsula (Nürnberg et al, 2011;Sakamoto et al, 2005), while in the western Okhotsk Sea (PC4) the IRD was mainly supplied from the northern and the western continental margins .…”

“…Unit 2 (9-381 cm) contains darkgray and green-gray sediments and is dominated by sandy silt and silty sand with abundant drop-stones of various sizes. The core has three distinct volcanic ash layers, reported by Zou et al (2015). Both L* and b* values simultaneously sharply decreased at three volcanic layers (Fig.…”

“…Age model establishments for core OS03-1 are reported by Zou et al (2015) based on oxygen isotope data and accelerator mass spectrometry (AMS) 14 C. Briefly, reference ages were determined on one 14 C dating of Neogloboquadrina pachyderma (sinistral) by accelerator mass spectrometry at a depth of 16-18 cm and δ 18 O stratigraphy of benthic foraminifera (Uvigerina spp.). The bottom of core OS03-1 was estimated to be about 180 ka with a resolution of~950 years/sample.…”

“…However, after entering the Okhotsk Sea, the radiogenic isotopes (Sr and Nd) data shows that river-derived terrigenous materials mainly deposited along the western continental slope of the Okhotsk Sea (Yasuda et al, 2014) and the coarse grains could not pass through the deep Deryugin Basin (Nürnberg and Tiedemann, 2004). A study of rare earth elemental ratios of sediment core OS03-1, however, indicated that fine particles derived from Amur River could be transported to the southern Okhotsk Sea (Zou et al, 2015).…”

“…Based on the abundances of radiolarian and diatom species, a mechanism controlling the variation in sea ice cover by the position of Aleutian Low (AL) has been proposed (Itaki and Ikehara, 2004;Katsuki et al, 2010). Zou et al (2015) found that the expanded sea ice cover occurred in MIS 5.3 was closely related to the Siberian High Index (Li and Liu, 2012). However, the IRD transport and the corresponding variations in sea ice cover in the southern Okhotsk Sea are still unclear due to the scarcity of direct indicator of paleosea-ice cover.…”