Isotopic feature and uranium dating of the volcanic rocks in the Okinawa Trough  

作　　者：HUANG Peng1,2, LI Anchun1, HU Ningjing2,3, FU Yongtao1& MA Zhibang4 1. Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 3. Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China 4. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 

出　　处：《Science China Earth Sciences》2006年第4期375-383,共9页中国科学（地球科学英文版）

摘　　要：Volcanic rocks from the northern and middle Okinawa Trough were dated by ura- nium-series dating method. Differential fractions using magnetic procedure were designed to separate samples. New report on the ages and isotopic data of rocks in the northern trough (especially black pumice) was discussed. Based on the uranium dates and Sr-Nd isotopic ratio, magmatic evolution process of the Okinawa Trough was noted. Firstly, there have been wide silicic volcanic activities in the Okinawa Trough from late Pleistocene to present, and the volcanic rocks can be divided into three subgroups. Secondly, magma generally came from PREMA source area under the Okinawa Trough. Magmatic evolution in the northern trough was similar to the middle, but different to the south. Finally, volcanic activities indicated that opening of the southern Okinawa Trough did not happen due to the collision between Luson Arc and Eurasian Plate until the early Pleistocene.Volcanic rocks from the northern and middle Okinawa Trough were dated byuranium-series dating method. Differential fractions using magnetic procedure were designed toseparate samples. New report on the ages and isotopic data of rocks in the northern trough(especially black pumice) was discussed. Based on the uranium dates and Sr-Nd isotopic ratio,magmatic evolution process of the Okinawa Trough was noted. Firstly, there have been wide silicicvolcanic activities in the Okinawa Trough from late Pleistocene to present, and the volcanic rockscan be divided into three subgroups. Secondly, magma generally came from PREMA source area under theOkinawa Trough. Magmatic evolution in the northern trough was similar to the middle, but differentto the south. Finally, volcanic activities indicated that opening of the southern Okinawa Trough didnot happen due to the collision between Luson Arc and Eurasian Plate until the early Pleistocene.

关 键 词：OKINAWA Trough  black pumice  uranium-series dating  SR-ND isotopic ratio  MAGMATIC evolution. 

分 类 号：P597.3[天文地球—地球化学]