Яндекс.Метрика

R.X.Zhu,B.Guo,Z.L.Ding,Z.T.Guo, A. Kazansky, G. Matasova

Выпуск: 5 , Том: 43 , Год издания: 2000
Сериальное издание: Chinese J. of Geophysics (Acta Geophysica Sinica)
Страницы: 621-634

Аннотация

A record of Gauss-Matuyama (G/M) geomagnetic polarity transition has been obtained from a loess section at Weinan. Shaanxi Province in China. Grain size and weathering intensity analysis demonstrate a rather weak pedogenesis in the oldest loess unit L33 was deposited. Rock-and paleo-magnetic investigations indicate that the remanent magnetization is mainly carried by magnetite and maghemite deposited as detrital grains. The record of the polarity transition based on ChRM directions of the low coercivity magnetic phase comprises 33 transitional directions. A pre-transitional excursion defined by 4 intermediate directions and lasting about 2.2 ± 0.13 ka appears to have occurred prior to the G/M polarity transition. Then, the record displays a N-S-N cycle with VGPs locating principally on American and Eastern-Asia longitudes. Finally, the reverse polarity is established with VGPs clustering in the Atlantic near southern Africa. The total duration of the directional change for the G/M transitions at Weinan, as derived from independent loess accumulation ratios, is about 9.43 ± 0.64. During the G-M polarity transition, the decrease in field intensity occurs.
индекс в базе ИАЦ: 019461