Dawson tephra, a widespread 29‐ka marker bed, in a marine core from Patton Seamount off the Alaska Peninsula and its potential marine–terrestrial correlation

Type Article
Date 2020-01
Language English
Author(s) Aoki Kaori1
Affiliation(s) 1 : Tokyo Metropolitan University, Hachioji CityTokyo, Japan
Source Journal Of Quaternary Science (0267-8179) (Wiley), 2020-01 , Vol. 35 , N. 1-2 , P. 93-101
DOI 10.1002/jqs.3176
Note Special Issue: Tephrochronology as a global geoscientific research tool
Keyword(s) Dawson tephra, Heinrich Stadial, late Pleistocene, marine sediment, MIS3, 2
Abstract

A tephra layer with normal grading in the sub‐bottom depth interval 119–122 cm in marine core SO202‐27‐6 was collected on Patton Seamount in the northeast North Pacific Ocean. Based on the geochemistry of volcanic glass shards determined by a wavelength dispersive electron probe micro‐analyser and an X‐ray fluorescence analyser, this layer is correlated to the Dawson tephra, a widespread late Pleistocene time marker tephra in Alaska and the Yukon. The age of the Dawson tephra in the core is 29.03 ± 0.178 ka (1 sigma) based on a published age model. The Dawson tephra is revealed to have been deposited in the transition from marine isotope stage 3 to 2, i.e. the last stage of Heinrich Stadial 3 derived from the ice‐rafted debris signal. According to the correlation between Greenland (NGRIP ice core) and this core, the Dawson tephra occupies the record immediately before inter stadial 4 in the δ18O stratigraphy of NGRIP. The Dawson tephra on Patton Seamount includes lithic fragments, which suggests that it was deposited not only by fall‐out but also in part via another mechanism, such as icebergs from the Cordilleran ice sheet or seasonal sea ice.

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Publisher's official version 9 4 MB Open access
Supplementary data for individual data of volcanic glass shards of the tephra layer (119–122 cm) in the sedimentary core SO202‐27‐6 and the AT tephra as the standard data 14 KB Open access
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