중기플라이스토세 전환기 동안 적도수렴대의 위도변화에 따른 중앙태평양 적도해역의 대기순환 및 해양 표층순환 변화 연구

Title
중기플라이스토세 전환기 동안 적도수렴대의 위도변화에 따른 중앙태평양 적도해역의 대기순환 및 해양 표층순환 변화 연구
Alternative Title
Response of Atmospheric and Surface Ocean Circulations in the Central Equatorial Pacific to the meridional movement of the Intertropical Convergence Zone during the Mid-Pleistocene Transition
Author(s)
서인아; 이용일; 형기성; 김원년; 유찬민
KIOST Author(s)
Hyeong, Kiseong(형기성)Kim, Wonnyon(김원년)Yoo, Chan Min(유찬민)
Publication Year
2015-11-09
Abstract
We investigated temporal changes in dust provenance, regional hydrology, and surface productivity in a deep-sea sediment core retrieved from the central equatorial Pacific (5°53N, 177°26W, 4,136 m depth) in order to determine the cause of a brief, but prominent, cooling event (1.1 - 0.8 Ma) occurred in the equatorial upwelling regions of the Atlantic and Pacific during the Mid-Pleistocene Transition (MPT). The radiogenic isotope composition (i.e., 87Sr/86Sr and εNd) and flux of the inorganic silicate fraction indicate that eolian dust was mainly derived from Southern Hemisphere to the study site before 0.8 Ma, but a gradual increase in the proportion of Asian dust deposition after 0.8 Ma. This shift in dust provenance was accompanied by an increased dust flux and a decrease in surface productivity and salinity. These changes can be best explained by the southward movement of the Intertropical Convergence Zone (ITCZ) and North Equatorial Counter Current (NECC) at the study site. Our results, together with previously published Atlantic data, suggest the northward displacement of the ITCZ between 1.1 and 0.9 Ma, and the southward displacement thereafter. Such meridional movement of the ITCZ during the MPT was in phase with the cooling and then warming trend in upwelling regions in the equatorial Pacific and Atlantic, which suggests ITCZ movement as a plausible cause of this brief cooling event.e of a brief, but prominent, cooling event (1.1 - 0.8 Ma) occurred in the equatorial upwelling regions of the Atlantic and Pacific during the Mid-Pleistocene Transition (MPT). The radiogenic isotope composition (i.e., 87Sr/86Sr and εNd) and flux of the inorganic silicate fraction indicate that eolian dust was mainly derived from Southern Hemisphere to the study site before 0.8 Ma, but a gradual increase in the proportion of Asian dust deposition after 0.8 Ma. This shift in dust provenance was accompanied by an increased dust flux and a decrease in surface productivity and salinity. These changes can be best explained by the southward movement of the Intertropical Convergence Zone (ITCZ) and North Equatorial Counter Current (NECC) at the study site. Our results, together with previously published Atlantic data, suggest the northward displacement of the ITCZ between 1.1 and 0.9 Ma, and the southward displacement thereafter. Such meridional movement of the ITCZ during the MPT was in phase with the cooling and then warming trend in upwelling regions in the equatorial Pacific and Atlantic, which suggests ITCZ movement as a plausible cause of this brief cooling event.
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/25085
Bibliographic Citation
추계지질과학연합학술대회, pp.65, 2015
Publisher
대한지질학회
Type
Conference
Language
English
Publisher
대한지질학회
Related Researcher
Research Interests

Paleomagnetism,Environmental Science,Geology,고지자기,환경과학,지질학

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