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Tephrostratigraphy and paleoenvironmental variation in late Quaternary core sediments of the southwestern Ulleung Basin, East Sea (Sea of Japan)
Author(s) -
Kim IlSoo,
Park MyongHo,
Ryu ByongJae,
Yu KangMin
Publication year - 2006
Publication title -
island arc
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.554
H-Index - 58
eISSN - 1440-1738
pISSN - 1038-4871
DOI - 10.1111/j.1440-1738.2006.00507.x
Subject(s) - tephra , lapilli , geology , quaternary , sediment , radiocarbon dating , geochemistry , structural basin , oceanography , paleontology , geomorphology , volcano , pyroclastic rock
Data on the late Quaternary tephra layers, tephrostratigraphy, geochemistry and environment were determined in two sediment cores from the southwestern part of Ulleung Basin (East Sea/Sea of Japan), representing marine‐oxygen isotope stages 1–3. The cores consist mainly of muddy sediments that are partly interbedded with silty sands, lapilli tephra and ash layers. The lapilli tephra layers (Ulleung‐Oki tephra, 9.3 ka) originating from Ulleung Island consist mainly of massive‐type glass shards, whereas the ash layers (Aira‐Tanzawa ash, 22.0–24.7 ka) derived from southern Kyushu Island are mainly composed of typical plane‐type and bubble‐wall glasses that are higher in SiO 2 and lower in Na 2 O + K 2 O than the lapilli tephra layers. Except for the tephra layers, fine‐grained sediments throughout the core sections are mostly of marine origin based on geochemical data (C/N ratios, hydrogen index, S2 peak) and Tmax. In particular, organic carbon contents increased during Termination I, probably as a result of an influx of the deglacial Tsushima Current through the Korea Strait.