Cryospheric and Oceanographic Evolution in the Arctic Makarov Basin Since the Early Pleistocene Revealed by Bulk Mineral Assemblages

Abstract

AbstractWe present the glacial history of the Makarov Basin (western Arctic Ocean) during the last ∼1.1 Myr, with sediment provenances using the newly refined chronostratigraphy of core ARA03B‐41GC02. According to the principal component analysis of the bulk mineral assemblages, felsic minerals were dominant, and their ratios (K‐feldspar/plagioclase and quartz/feldspars) indicated that sediment supply to the Makarov Basin was mainly from the Siberian margin and partly from northern North America, including the Canadian Arctic. However, their occurrence did not vary significantly between interglacials and glacials due to the mixed sources. In contrast, clinopyroxene and dolomite indicated specific sediment origins from the eastern Siberian margin and northern North America, respectively. The clinopyroxene content followed an eccentricity cycle (∼100‐Kyr) during the early to middle Pleistocene, suggesting that the eustatic sea level changes may have influenced its input from the eastern Siberian margin. The dolomite, transported primarily by icebergs from the Arctic sector of the Laurentide Ice Sheet (LIS) in northern North America, has also followed the same cycle since the early Pleistocene. Thus, the mineralogical signals highlight that sediment origins and transport processes in the Makarov Basin were related to ice sheet evolution at the eccentricity cycle. In addition, dolomite deposition in the Makarov Basin began by the early Pleistocene (∼790 ka), ∼150 ka earlier than in previous North Atlantic records (∼640 ka), indicating the earlier LIS calving in the Arctic sector than in the Atlantic sector.