Yamada, Kazuyoshi and Fukusawa, Hitoshi (1997): Climatic changes recorded in the deep-sea sediments (ODP Site 974B) of the Mediterranean Sea during the last 4.5 Ma

Leg/Site/Hole:
ODP 161
ODP 161 974
Identifier:
1997-071808
georefid

Creator:
Yamada, Kazuyoshi
Tokyo Metropolitan University, Division of Geography, Tokyo, Japan
author

Fukusawa, Hitoshi
Nihon University, Japan
author

Identification:
Climatic changes recorded in the deep-sea sediments (ODP Site 974B) of the Mediterranean Sea during the last 4.5 Ma
1997
In: Ono, Yugo (prefacer), Endo, Kunihiko (prefacer), Iwata, Shuji (prefacer), The significance of the Himalayan-Tibetan Massif for global changes
Tokyo Chigaku Kyokai, Tokyo, Japan
106
2(951)
218-225
We attempted to clarify changes of magnetic susceptibility and clay mineralogy of the deep-sea sediments in ODP site 974B during the last 4.5 Ma. These sediments are composed mainly of calcareous nannoplankton ooze with organic matters and eolian dusts. Sequential changes of illite crystallinity, expressing as full width of half maximum of 10Aa peaks by X-ray diffraction patterns, indicate changes of dry-wet climatic conditions in a supply area. Due to the atmospheric circulation pattern influenced by the Himalayan-Tibetan Plateau, the tropical easterly jets have lead northern Africa to dry conditions. So, it is possible to settle the uplift age of the Himalayan-Tibetan Plateau from the beginning age of dry climatic condition in northern Africa. As a results, we could clarify two evidences as follows: 1) Illite concentrations and magnetic susceptibility indicate concentrations of eolian dust carrying from northern Africa have increased from 3.5 Ma ago. In other words, the recent atmospheric circulation, that is carrying eolian dust into the Mediterranean Sea, has been confirmed from 3.5 Ma ago. 2) Based on oscillations of illite crystallinity during the 4.5 Ma, the northern Africa region became dry condition 0.8 Ma ago. We thought that this event of 0.8 Ma was caused by the uplift of the Himalayan-Tibetan Plateau.
Japanese
Serial
Coverage:Geographic coordinates:
North:40.2100
West:12.0800East: 12.0800
South:40.2100

Quaternary geology; Oceanography; Cenozoic; changes; clay mineralogy; deep-sea environment; Leg 161; magnetic susceptibility; magnetization; marine environment; marine sediments; Mediterranean Sea; monsoons; natural remanent magnetization; Ocean Drilling Program; ODP Site 974; paleoclimatology; paleomagnetism; Pleistocene; Quaternary; remanent magnetization; sediments; Tyrrhenian Sea; upper Pleistocene; West Mediterranean; wind transport;

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