Environmental changes reflected by sedimentary records of detrital minerals in the eastern Laptev Sea over the past 12 kyrs

Abstract

The Siberian Arctic shelf is important for sediment transport and deposition, shaped by complex interactions among river input, permafrost erosion, and sea ice processes. Despite advances in understanding these systems, the sedimentary evolution of the eastern Laptev Sea shelf over the Late Pleistocene, and its response to sea-level and climate changes, remains unclear. Here, we analysed light and heavy minerals, coarse components and sediment smear slide estimations from a sediment core collected on the paleo-floodplain of the Yana and Lena rivers, compared them with surface sediments. The results reveal four distinct sedimentary periods: (1) a river floodplain phase (∼12–10.4 ka BP), characterized by fluvial deposits rich in micas, limonite, quartz, and plagioclase; (2) a fine-grained, organic-rich phase linked to permafrost erosion and/or island flattening under warmer climate conditions and rapid sea level rising (∼10.4–8.2 ka BP), with abundant authigenic barite, pyrite, and siderite; (3) a peak fluvial input phase during continuous sea level rise (∼8.2–5.0 ka BP), marked by increased volcanic glass and initially intensified sea ice; (4) the modern sedimentary regime (∼5.0–0 ka BP), with decreased fluvial input and strengthened sea ice transport. Since ∼2 ka BP, increased silt content indicates that more sediment originates from anchor ice on the shelf. Variations in detrital minerals, such as hypersthene, suggest sediment contributions from the western Laptev Sea, Lena, Khatanga, and Anabar Rivers, and even the Taymyr Peninsula and Kara Sea, indicating an eastward shift in the Transpolar Drift System.