Paleo-latitude of the Intertropical Convergence Zone in the Northeast Pacific during Late Cenozoic SCOPUS KCI

Paleo-latitude of the Intertropical Convergence Zone in the Northeast Pacific during Late Cenozoic
Hyeong, K.; Kim, K.-H.; Chi, S.-B.; Yoo, C.M.
KIOST Author(s)
Hyeong, Kiseong(형기성)Chi, Sang Bum(지상범)Yoo, Chan Min(유찬민)
Publication Year
The Intertropical Convergence Zone (ITCZ), where the southeast and northeast trade winds converge, is the effective climatological barrier that separates the southern and northern hemispheres in dust budget. Asian and N. American dusts dominate in the Pacific north of the ITCZ, while Central and S. American dust prevails south of the ITCZ. In order to understand the nature of latitudinal and depth-related variations of mineral composition in terms of relative position to the ITCZ, deep-sea core sediments were collected from 9°N to 17°N at a 2° interval along the 131.5°W meridian and analyzed for mineral composition. The amount of illite in surface sediments decreases gradually from 65% at 17°N to 31% at 9°N. In contrast, smectite increases from 11% to 56% southward. The observed mineralogical, variation toward the ITCZ is attributed to the increased supply of volcaniclastic material transported via the southeast trade winds from the Central and South America source regions. Smectite-illite transition, a phenomenon that the amount of smectite increases over illite, occurs at around 10°N, the northern margin of the ITCZ. This result indicates that the change in latitudinal position of the ITCZ in geologic past could be recorded as a form of smectite-illite transition in deep-sea cores. The studied cores show down-core variation of mineral composition from illite-rich at the surface to smectite-rich clay suit at depths, similar to the latitudinal variation. The smectite-illite transitions observed in these cores are likely the records of changes in latitudinal position of the ITCZ. The depth and age of smectite-illite transition is getting shallower and younger toward equator, implying that the ITCZ was located farther north during late Tertiary and has shifted southward to the present position of 5°N-10°N.
Bibliographic Citation
Ocean and Polar Research, v.26, no.2, pp.245 - 253, 2004
Korea Ocean Research and Development Institute
Cenozoic; deep sea; deep-sea sediment; intertropical convergence zone; mineralogy; paleolatitude; sediment core; smectite; Pacific Ocean; Pacific Ocean (Northeast)
Deepsea sediment; ITCZ; Mineral composition; Northeast Pacific
Document Type
Korea Ocean Research and Development Institute
Related Researcher
Research Interests

deep sea mineral resources,deep sea sediments,심해저 광물자원,심해저 퇴적물,심해 환경

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