Mineral Chemistry Indicates the Petrogenesis of Rhyolite From The Southwestern Okinawa Trough

CHEN Zuxing; ZENG Zhigang; WANG Xiaoyuan; ZHANG Yuxiang; YIN Xuebo; CHEN Shuai; MA Yao; LI Xiaohui; QI Hanyan

首页> 中文期刊> 《中国海洋大学学报：英文版》 >Mineral Chemistry Indicates the Petrogenesis of Rhyolite From The Southwestern Okinawa Trough

Mineral Chemistry Indicates the Petrogenesis of Rhyolite From The Southwestern Okinawa Trough

开具论文收录证明 >>

期刊封面封底目录下载 >>

文献代查 >>

页面导航

摘要
著录项
相关主题

摘要

To reveal the petrogenesis of rhyolite from the southwestern Okinawa Trough, the mineral chemistry of plagioclase, orthopyroxene, amphibole, quartz and Fe-Ti oxide phenocrysts were analyzed using an electron microprobe, and in suit Sr and Ba contents of plagioclase analysed by LA-ICPMS were chosen for fingerprinting plagioclases of different provenances. Results indicate an overall homogeneous composition for each of the mineral phases except for plagioclase phenocrysts which have a wide range of composition(An=39~88). Plagioclase crystals characterized by An contents of >70 are not in equilibrium with their whole-rock compositions, and coarse-sieved plagioclase phenocryst interiors record high An contents(>70) and Sr/Ba ratios(>7), which are similar to the those of plagioclase crystals in basalt. Therefore, these crystals must have been introduced to the rhyolitic magma from a more mafic source. Equilibrium temperatures estimated using orthopyroxene-liquid, iron–titanium oxide, titanium-in-quartz and amphibole geothermometers show consistent values ranging from 792 to 869℃. The equilibrium pressure calculated using amphibole compositions is close to 121 MPa which corresponds to an approximate depth of 4 km. The fO_2 conditions estimated from Fe-Ti oxides and amphiboles plot slightly above the NNO buffer, which indicates that the rock formed under more oxidized conditions. Our results suggests that petrogenesis of the rhyolite due to basaltic magma ascend with the high An and Sr/Ba plaigoclases from deep magma chamber into the shallow chamber where the fractional crystallization and crustal assimilation happened. It also indicates that a two-layer magma chamber structure may occur under the southwestern Okinawa Trough.

著录项

来源
《中国海洋大学学报：英文版》 |2017年第6期|1097-1108|共12页
作者
CHEN Zuxing; ZENG Zhigang; WANG Xiaoyuan; ZHANG Yuxiang; YIN Xuebo; CHEN Shuai; MA Yao; LI Xiaohui; QI Hanyan;
展开▼
作者单位

Key Laboratory of Marine Geology and Environment;

Institute of Oceanology;

Chinese Academy of Sciences;

Qingdao 266071;

P. R. China;

Laboratory for Marine Mineral Resources;

Qingdao National Laboratory for Marine Science and Technology;

Qingdao 266071;

P. R. China;

University of Chinese Academy of Sciences;

Beijing 100049;

P. R. China;

展开▼
原文格式 PDF
正文语种 chi
中图分类海洋学;
关键词
geothermobarometry; oxygen; fugacity; xenocrysts; magma; evolution; rhyolite; Okinawa; Trough;

Mineral Chemistry Indicates the Petrogenesis of Rhyolite From The Southwestern Okinawa Trough

摘要

著录项

相关主题

期刊订阅