Abstract
Abstract. Rock magnetic, biochemical and inorganic records of the sediment cores PG1351 and Lz1024 from Lake El'gygytgyn, Chukotka peninsula, Far East Russian Arctic, were subject to a hierarchical agglomerative cluster analysis in order to refine and extend the pattern of climate modes as defined by Melles et al. (2007). Cluster analysis of the data obtained from both cores yielded similar results, differentiating clearly between the four climate modes warm, peak warm, cold and dry, and cold and moist. In addition, two transitional phases were identified, representing the early stages of a cold phase and slightly colder conditions during a warm phase. The statistical approach can thus be used to resolve gradual changes in the sedimentary units as an indicator of available oxygen in the hypolimnion in greater detail. Based upon cluster analyses on core Lz1024, the published succession of climate modes in core PG1351, covering the last 250 ka, was modified and extended back to 350 ka. Comparison to the marine oxygen isotope (δ18O) stack LR04 (Lisiecki and Raymo, 2005) and the summer insolation at 67.5° N, with the extended Lake El'gygytgyn parameter records of magnetic susceptibility (κLF), total organic carbon content (TOC) and the chemical index of alteration (CIA; Minyuk et al., 2007), revealed that all stages back to marine isotope stage (MIS) 10 and most of the substages are clearly reflected in the pattern derived from the cluster analysis.
Highlights
The climate history of tOhecCehuaknotkSa cpeineinnsculea, Far East Russian Arctic, for the last 250 ka was revealed by a multidisciplinary study on sediment core PG1351 from Lake El’gygytgyn
Side-by-side plots of the rock magnetic parameters κLF and S-ratio, TiO2 content, chemical index of alteration (CIA), total organic carbon content (TOC), and biogenic silica (BSi) versus age (Fig. 3) confirms the overall similarity in the sediment composition of cores PG1351 and Lz1024, which are already visible in the high-resolution records of magnetic susceptibility (Fig. 2)
The gradual changes in the sedimentary composition as an indicator of available oxygen in the hypolimnion during glacial/non-glacial periods and the lack of mixing in the water column can be resolved in greater detail by using statistical approaches
Summary
The climate history of tOhecCehuaknotkSa cpeineinnsculea, Far East Russian Arctic, for the last 250 ka was revealed by a multidisciplinary study on sediment core PG1351 from Lake El’gygytgyn (see Brigham-Grette et al, 2007, and references therein). Prior efforts to interpret core PG1351 in terms of specific climate modes (Melles et al, 2007) have not attempted to differentiate among apparent compositional variations that exist within intervals assigned to warm climate modes, or to identify possible transitional phases between peak warm and cold intervals. A statistical approach to the analysis of the existing data from core PG1351 and new rock magnetic and geochemical data from a second, longer core, Lz1024, provides a method for further refining the modes of variability evident in the sediments of Lake El’gygytgyn.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
