Diatoms from Lake Kushu: A pilot study to test the potential of a Late Quaternary palaeoenvironmental archive from Rebun Island (Hokkaido Region, Japan). (15th May 2016)

• Record Type: Journal Article
• Authors: Schmidt, Mareike; Tarasov, Pavel E.; Hoelzmann, Philipp; Meyer, Hanno; Leipe, Christian
• Is Part Of: Journal of Asian earth sciences. Volume 122(2016)
• Page Start: 106
• Page End: 122
• Publication Date: 2016-05-15
• Subjects: Diatoms -- Late quaternary -- Hokkaido -- Marine transgression -- Oxygen isotopes -- Sediment geochemistry; Earth sciences -- Asia -- Periodicals; Sciences de la terre -- Asie -- Périodiques; Earth sciences; Asia; Periodicals; 555.05
• DOI: 10.1016/j.jseaes.2016.03.005
• Languages: English
• ISSNs: 1367-9120

Abstract

Highlights: First analysis of modern diatom assemblage from Rebun and Rishiri islands. Pilot study tests the potential of a 19.5 m core as a high-resolution archive. Diatom and geochemistry analyses indicate three main lake phases since 16.6 kyr BP. Abstract: Rebun Island is a key research area for the Baikal-Hokkaido Archaeology Project to better understand the dynamics of the Neolithic hunter–gatherers in the NW Pacific region. Hence, the ca. 19.5 m sediment core RK12 spanning the last ca. 16.6 cal. kyr BP was obtained from Lake Kushu. Our aim is to test its potential as a high-resolution multi-proxy archive. Here, we used diatoms to investigate the modern ecosystem of Lake Kushu and its surrounding area on Rebun Island and of Hime-numa Pond on Rishiri Island and selected core samples for comparison. Modern diatom and stable isotope analyses show well-mixed freshwater bodies with eutrophic, alkaline conditions. The fossil diatom and geochemical sediment analyses display three phases that represent major changes in the lake development: (i) a marshy phase (ca. 16.6–10 cal. kyr BP); (ii) a brackish water lagoon phase (ca. 10–6.6 cal. kyr BP); and (iii) a freshwater lake phase (since ca. 6.6 cal. kyr BP). This shows the major role of the post-glacial climate amelioration, global sea-level rise and marine transgression in the development of this landscape. Further analyses will provide a palaeolimnological record at (sub-)decadal resolution that will facilitate the interpretation of the hunter–gatherer dynamics.