## 4 Discussion
### Provenance Discrimination  
As the landmasses surrounding the Arctic Ocean are composed of different geological terrains, the mineralogical and isotopic signals are distinct [2; 34]. We utilized the bulk mineralogy and Nd isotope in core ARA09C-St03 to identify changes in sediment provenances in the Chukchi Sea since the late MIS 5. Major potential sediment provenances in the study area could be considered in terms of two regions: the North American and Eurasian regions [18; 23]. Tables 1-3 show the mineralogy and \(\varepsilon\)Nd values of potential provenances. The North American region was subdivided into the Canadian Archipelago and Beaufort Sea, and the Eurasian region was subdivided into the Chukchi Sea, East Siberian Sea, and Laptev Sea. Sediment input from the North American region can generally be characterized using the combination of dolomite, Q/F (quartz/feldspar), and K/C (kaolinite/chlorite) ratios [8; 18; 22]. Dolomite was a common mineral in the marine sediments from the western Arctic and interpreted as an indicator of sediment input from the Canadian Archipelago, which constitutes Paleozoic carbonate terranes, particularly Banks Island and Victoria Island [8; 14; 18; 35]. Quartz, a common mineral throughout the Arctic, is difficult to use as a provenance indicator, but when combined with feldspar (Q/F ratio), it may yield important information on source areas and transport pathways [8; 14; 18]. Likewise, the K/C ratio can also be used as a useful indicator [18; 19; 20]. Sediment in the Eurasian Arctic shelf seas is characterized by almost no dolomite content and low Q/F and K/C ratios (Tables 1 and 2). They could be characterized in detail by the clay mineral assemblage. The Siberian Sea continental shelf closest to the study area is supplied with illite-rich sediment from the Indigirka and Kolyma rivers and forms an illite belt [20]. The Laptev Sea is characterized by a high smectite content. The main sources of smectite are the Ob and Yenisei rivers in the Kara Sea and the Khatanga river in the Laptev Sea [15; 20]. In addition, the Nd isotope ratio of silicate particles remains essentially unaltered by weathering, transport, or sedimentation and can be a powerful tool for tracing the provenance of the terrigenous portion of marine sediment [25]. Nd isotopes can be used to better constrain the sediment provenances with similar mineral compositions in the Arctic. Discrimination plots of dolomite vs. Q/F ratio and illite vs. K/C ratio in Figures 4 and 5 can be utilized to determine the provenance of sediments in core ARA09C-St03. The former plot can distinguish the Canadian Archipelago and Beaufort Sea in the North American region, and the latter graph can distinguish the East Siberian Sea, Chukchi Sea, and Laptev Sea. In cycle 3, Units 6 and 8 are almost identical to the composition of the East Siberian Sea. However, Unit 7, which has a relatively high IRD content, contains sediments sourced from the Canadian Archipelago. The lowest \(\varepsilon\)Nd values of Unit 7 support the sediment supply from the Canadian Archipelago. During cycle 2, Unit 5, consisting of yellowish-gray to gray mud, was plotted in an area of the Siberian Sea. \(\varepsilon\)Nd values are also represented in the range of values of the East Siberian Sea. By contrast, Unit 4 sediments are characterized by high dolomite content and K/C ratio, indicating that these sediments' inflow, mainly from the North American regions, particularly the Canadian Archipelago. In cycle 1, Unit 3 samples are mainly located around the East Siberian Sea, but they might be partially influenced by the Chukchi Sea. Unit 2, which contains the most IRD content, clearly represents the sediment supply from the Beaufort Sea, unlike the other IRD layers. The \(\varepsilon\)Nd value was also the lowest in the core, which is most similar to that of the Mackenzie River in North America. Unit 1 was mainly sourced from the East Siberian Sea, but some samples rich in dolomite are located close to the Canadian Archipelago.