Southward shift of the Intertropical Convergence Zone due to Northern Hemisphere cooling at the Oligocene-Miocene boundary SCIE SCOPUS

Cited 6 time in WEB OF SCIENCE Cited 7 time in Scopus
Title
Southward shift of the Intertropical Convergence Zone due to Northern Hemisphere cooling at the Oligocene-Miocene boundary
Author(s)
Hyeong, Kiseong; Lee, Jongmin; Seo, Inah; Lee, Mi Jung; Yoo, Chan Min; Khim, Boo-Keun
KIOST Author(s)
Hyeong, Kiseong(형기성)Yoo, Chan Min(유찬민)
Publication Year
2014-08
Abstract
The Mi-1 glaciation (ca. 23 Ma), which marks the Oligocene-Miocene boundary, was an aberrant cooling event that led to a build-up of the Antarctic ice sheet, which reached the near-modern volume (or greater) from its ephemeral or partial existence. An increase of similar to 1% in the delta O-18 of benthic foraminifera during this interval has been attributed to the development of Antarctic ice sheets and deep-water cooling. Without definitive evidence, Northern Hemisphere (NH) glaciation has not been a material consideration for the delta O-18 increase. Here we investigate the interhemispheric temperature contrast during Mi-1, with the movement of the Intertropical Convergence Zone (ITCZ) at a site (10 degrees 31'N) in the East Pacific (Integrated Ocean Drilling Program Site U1333), to understand NH cooling and the possibility of NH glaciation. The measured Nd-143/Nd-144, Sr-87/Sr-86, and clay mineral compositions of eolian dust fractions indicate unequivocally the deposition of Asian dust during Mi-1, and of Central American and South American dust before and after Mi-1. This is attributed to the southward displacement of the ITCZ over Site U1333 during Mi-1. The ITCZ shifts toward the warmer hemisphere. Thus our results suggest that the cooling during Mi-1 was more significant in the NH than in the Southern Hemisphere, which underwent a sudden expansion of continental ice sheets. Our data call for a forcing mechanism to drive significant NH cooling during this episode. Based on the available data, we propose that the widespread growth of NH ice sheets and/or changes in the production of North Atlantic-origin deep water could be possible causes of the NH cooling at that time.
ISSN
0091-7613
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/2763
DOI
10.1130/G35664.1
Bibliographic Citation
GEOLOGY, v.42, no.8, pp.667 - 670, 2014
Publisher
GEOLOGICAL SOC AMER, INC
Subject
ANTARCTIC ICE-SHEET; CARBON-CYCLE; CLIMATE; SEDIMENT; SEA; VARIABILITY; DUST
Type
Article
Language
English
Document Type
Article
Publisher
GEOLOGICAL SOC AMER, INC
Related Researcher
Research Interests

Ocean Geology,Mineral resources,해양지질,광물자원

Files in This Item:
There are no files associated with this item.

qrcode

Items in ScienceWatch@KIOST are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse