Basic Study on Hemispheric Climatic Changes and on Transition of Paleoenvironments in Huge Tectonic Lakes.
Grant-in-Aid for Overseas Scientific Survey.
|Allocation Type||Single-year Grants|
|Research Institution||Mineralogical Institute, University of Tokyo|
TOYODA Kazuhiro Faculty of Science University of Tokyo Research Assistant, 理学部, 助手 (10207649)
CHRISTIAN Sc スイス工科大学, 準教授
MICHAEL Kuzmin Institute of Geochemistry, Acad. Sci. Russia Director (Professor), 地球化学研究所, 教授
LOUIS Scott Orange Free State University Assistant Professor, 準教授
TAKEMURA Keiji Faculty of Science, Kyoto University Associate Professor, 理学部, 助教授 (00201608)
OGURA Kazuko Faculty of Science, Tokyo Metropolitan University Assistant, 理学部, 助手 (20087117)
ISHIWATARI Ryoshi Faculty of Science, Tokyo Metropolitan University Professor, 理学部, 教授 (90087106)
HIBINO Koichiro Miyagi Argicultural College Professor, 教授 (10004417)
HORIE Shoji Emeritus Professor, Kyoto University, 名誉教授 (90025320)
CHRISTIAN Schluchter Institut fur Ingenieurgeoogie, ETH Zurich Assistant Professor
|Project Period (FY)
Completed(Fiscal Year 1991)
|Keywords||Huge tectonic lake / Tanganyika / Baikal / Climatic change (Pleistocene - Holocene) / 洪積世〜沖積世 / 南北両半球 / ソ-ルトパン / バイカルコア分析計画|
1. PROGRAM CARRIED OUT
In our joint work on the present theme, we had concentrated our study to South Africa and lake Baikal ; the most distinguished features as tectonic lake are observed in both typical tectonic lakes such as Tanganyika and Baikal. As the first step to study Lake Tanganyika, we started stratigraphic study on the core sample obtained in Verloren Vlei because Lakes Tanganyika and Malauii is regarded as one unit of African tectonism extending to southern coast.
On the other hand, paleolimnological study is carried out in Lake Paikal by Russian and American joint work supported also by Japanese and Netherlanders. And we obtained tentative example of 4.61m long core in order to compare the succesion of lake type between Biwa and Baikal. We already obtained very valuable data. These academic data are printed in IPPCCE News Letter.
As the result of these two ancient lake sediments, we could obtain clue to study two distinguished tectonism in the world.
In South Africa,
we obtained 50m long core and pollen analytical work was done by Dr. Meadow and granurometric work was carried out by people under auspice of Prof. Parkington, University of Cape Town. On the other hand, we obtained core sample of 300, 000 years old at Lake Saltpan in which pollen analytical work was carried out by Dr. Sara Kerr under the guidance of Profs. Scott and Partridge. Althouth it is still difficult to clarify the whole climatic succession, it is clear that South Africa had been suffered by cold climate during the correlating age with the Northern Hemisphere in the Pleistocene. For result on geomagnetic feature, it is unfortunately not successful for the reason of lot of non-magnetic minerals existence (below 3 x 10^<-7> emu/cm^3).
In the case of Baikal, 4.61m core had verified the existence of two units of environments. In this regard, Pleistocene-Holocene boundary seems to be 1.5 meters deep level. Probably the sedimentation rate might have been 0.01mm at the 700m deep spot in the northern basin. Above that 1.5m level, plenty of planktonic diatom fossils were found on the contrast to poor amount of diatom fossils below that level. Above that 1.5m is regarded as Holocene warm climate deposit. That age might cause high productivity. It is similar with the case of Lake Biwa sediments. Regarding pollen grains, we can find out colder climate substage below 1.5m level denoting Wurm climate fluctuation. From the view-point of organic chemistry, terrestrial production as forest coincides with the autochthonous variation of lake organism such as planktonic diatom and also zooplankton composition. It is also comparable with Lake Biwa history supporting the possibility of establishing chronology in the Northern Hemisphere by both Lakes biwa and Baikal. Less
Research Output (12results)