摘要
根据测定冲绳海槽０８０、０８２两岩芯中放射性同位素和化学元素的垂直 分布，基于２３０Ｔｈ／２３２Ｔｈ放射性活度比值，确定了末次冰期和全新世之间确切的 地层年代。测得资料表明，在全新世和晚更新世期间沉积物中元素的丰度有很 大的变化，反映了冲绳海槽在不同历史时期沉积环境的变迁和物质来源的差 异。
Chemical elements Ca. Sr. Mn. Fe. Cu and isotopes 232Th、230Th in two cores from Okinawa Trough have been determined. The major results of this study are that: 1. Based on the 230Th/ 232 Th activity ratio, the Younger Dryas age was about 10 840 a B. P. Profile of 232 Th activity indicated that 232 Th activity in the core Were relatively low during the Holocene, but were high during the pleistocene. Because 232Th is just as the terrigenous sediment indi- cater, reflecting a greater supply of sediment due to glaciation and sea level lowing in the Okinawa Trough. 2. In the west part of the Okinawa Though, chemical elements Fe.Mn and Cu contents in the core 080 were lower in the Holocene than the Pleistocene, indicating that the terrigenous materisls decreased Sharply from the Pleistocene to the Holocene due to the sea level rising. However, In the central part of the Okinawa Though, the contents of the Fe,Mn and Cu in the core 082 were increased from the Pleistocene to the Holocene, this is because the sediments of the Holocene section were deposited with clay-sized particles,and in the Pleistorcene section the sediments were formed of silt and sand. 3. The contents of Ca and Sr were higher in the. Holocene than the Pleistocene, reflecting that bi- ological sedimentation processes increas in Okinawa Though during the Holocene. On the other hand, indicating that the lower Ca and Sr contents in the Pleistocene were diluted by the terrigenous materi- als.
出处
《海洋科学》
CAS
CSCD
北大核心
1996年第5期55-59,共5页
Marine Sciences
基金
国家自然科学基金资助项目!49376264
关键词
冲绳海槽
沉积物
化学元素
更新世
全新世
Okinawa Trough, Elements profile, Varied sedimentary environment
