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| Isotopic feature and uranium dating of the volcanic rocks in the Okinawa Trough | |
| 摘 要： | 1 Introduction The Okinawa Trough(OT) extends for ~1200 km between Taiwan and Kyushu, and is an incipient back-arc basin bounded by the Ryukyu Arc to the south and east, and by Diaoyudao Uplift Belt1,2] (Tai- wan-Sinzi Belt3]) to the north and west. Drastic faults and volcanic activities are the typical features in the OT. Generally, the OT is divided into three segments (north, middle and south) by the Tokara Strait and Kerama Gap4]. The geological features, such as tec- tonics, m… |
| 收稿时间： | 31 January 2005 |
| 修稿时间： | 23 November 2005 |
Isotopic feature and uranium dating of the volcanic rocks in the Okinawa Trough |
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| Authors: | HUANG Peng LI Anchun HU Ningjing FU Yongtao MA Zhibang |
| Institution: | 1. Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 2. Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China 3. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China;Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China 4. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China |
| Abstract: | 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. |
| Keywords: | Okinawa Trough black pumice uranium-series dating Sr-Nd isotopic ratio magmatic evolution |
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