【摘要】 本文采用最新设计的UTS-A型取心器采取岩心,并以10—15cm间距在该湖盆共采集占地磁标本为正极性,为布容正向期.但3%的样品为负极性,并构成数段散布于正极性地层中,经研究表明,它完整地记录了布容期47万年来8个反向极性事件.该湖盆环境稳定,沉积速率快,是研究短期反极性事件的良好场所.更多还原

【Abstract】 The Tianyang Volcanic Lake is located in the southeast of the Leizhou Peninsula, and the lake basin has continuously filled with Quaternary porous sediments in thickness of 222.42m. As the newly designed UTS-a type corer and the plastic liner were used for sampling, the average core recovery percentage was 98.4%, and the original texture of the core was kept in good condi-tion. 1964 palaeomagnetic samples were collected (with intervals of 10-15m) and measured in Eidgenossiche Technische Hochschule (Zurich, Swiss) and Guiyang Geochemistry Institute. The results indicate that 97% of the samples belong to normal polarily in Brunhes normal epoch with magnetic dips 30. The other 3% samples were negative-polarity, distributed in the normal-polarity strata separateiy, which represent 8 reversed polarity events. The latest event occured at the core depth of 2.7m with a C14 age of 2900 a. B. P., suggested to be the Starno event. The second event (from up to down) occured at the depth of 6.45-7.38m with 12000-13000 a. B. P. in age, corresponding to the Gothenburg event. The third event occured at the depth of 28.60-32.23m with 30000 a. B. P. in age, which may be the Mungo event. The fourth event occured in 58-65m with 65000 a. B. P. in age, corresponding to the Laschamp event. There were another four reversed-polarity events below the Laschamp event occurring in the core at depths of 96.10-101.40m, 153.80-159.46m, 191.87-203.00m and 219.39-220.16m respectively. Based on the dating results of K-Ar method, Uraniunl-series age method and thermolumi-nescent method, they were 100,000 a. B. P., 200,000 a. B. P., 320,000 a. B. P. and 40,000 a. B. P. in age respectively, corresponding to the events of Blake, Taimace, Levantine (BiwaD) and BiwaE respectively.The environmental parameters of the Tianyang Lake Basin are stable, with a high deposition rate and little disturbance of benthic microorganisms, so the basin has more opportunities to retain the directions of the original residual magnetic field and therefore is a suitable place for the researches of the short-termed reversed-polarity events. Data indicate that these 8 reversed-polarity events which occured in the Brunhes epoch had been recorded completely in the Tianyang Lake Basin,更多还原