The Quaternary Research (Daiyonki-Kenkyu)
Online ISSN : 1881-8129
Print ISSN : 0418-2642
Current issue
Showing 1-4 articles out of 4 articles from the selected issue
Special issue on the Symposium “Stratigraphy and chronological criteria”
  • K. Mizuno, T. Suzuki, M. Okada, K. Okumura
    2018 Volume 57 Issue 5 Pages 129-130
    Published: October 01, 2018
    Released: November 09, 2018
    JOURNALS RESTRICTED ACCESS
    Download PDF (183K)
  • Takehiko Suzuki
    2018 Volume 57 Issue 5 Pages 131-142
    Published: October 01, 2018
    Released: November 09, 2018
    JOURNALS RESTRICTED ACCESS

    This paper aims to review the current situation of tephra studies in Japan and overseas, focusing on methods of identification, dating, applications in palaeoclimatology, and development of archives of standard tephra samples. The author refers to recent intercomparison of tephrochronology laboratories with EPMA data on the geochemistry of volcanic glasses and developments notably in LA-ICP-MS that are revolutionizing the analysis of tephras. For determination of eruption ages of tephras, recent dating methods ranging from radiometric methods to age modeling tools such as ice-core-based age dating, together with palaeoclimatological studies are reviewed. In particular, the author overviews recent studies reporting detections of intercontinentally distributed tephras identified in the Greenland ice core and related issues.

    Download PDF (1191K)
  • Takashi Nirei, Misao Hongo
    2018 Volume 57 Issue 5 Pages 143-155
    Published: October 01, 2018
    Released: November 09, 2018
    JOURNALS RESTRICTED ACCESS

    The pollen biostratigraphy of the late Early to the Middle Pleistocene in Central Japan comprises five superbiozones : the Quercus-Metasequoia, the Fagus-Quercus, the Cryptomeria-Fagus, the Cyclobalanopsis-Cupressaceae, and the Pinaceae-Cryptomeria Superbiozones, in ascending order. These superbiozones were established by pollen biohorizons and association of paleovegetation. Pollen biohorizons were recognized by organizing the correspondence between local pollen zones from 8 sites and oxygen marine isotope stages. The framework of paleovegetation changed step by step at about the same time as terminations of oxygen isotope stratigraphy. In particular, paleovegetation was warm-temperate deciduous broad-leaved forest accompanied by Neogene elements (for example Metasequoia) during the depositional period of the Quercus-Metasequoia Superzone (below Termination X), warm-temperate deciduous broad-leaved forest accompanied by temperate evergreen conifer during the depositional period of the Fagus-Quercus Superzone (Termination X to VII), warm-temperate deciduous broad-leaved forest with few Quercus accompanied by temperate evergreen conifers during the depositional period of the Cryptomeria-Fagus Superzone (Termination VII to V), warm-temperate evergreen broad-leaved forest during the depositional period of the Cyclobalanopsis-Cupressaceae Superzone (Termination V to IV), and temperate evergreen coniferous forest accompanied by deciduous broad-leaved forest with many Pinaceae conifers during the depositional period of the Pinaceae-Cryptomeria Superzone (above Termination IV).

    Download PDF (2265K)
  • Sumiko Tsukamoto
    2018 Volume 57 Issue 5 Pages 157-167
    Published: October 01, 2018
    Released: November 09, 2018
    JOURNALS RESTRICTED ACCESS

    The developments in luminescence dating methods, especially regarding feldspar dating techniques and rock surface and burial dating, over the past decade are summarized. Post-IR IRSL (pRIR) and pulsed IRSL methods for feldspar have been developed to reduce anomalous fading (athermal loss of signals). The pRIR signal at higher stimulation temperatures is generally more stable (fades less) ; however, the signal is difficult to bleach, which is problematic for water-lain sediments. The pulsed IRSL signal has both advantages, being athermally stable and quickly bleachable. Newly developed methods for measuring surface exposure and burial ages for rock surfaces and gravels are also introduced.

    Download PDF (1097K)
feedback
Top