Oxygen isotope constraints on fluid flow during eclogitization in the Sulu terrane

作     者：郑永飞 傅斌 龚冰 肖益林 魏春生 李曙光 

作者机构：China Department of Earth and Space Scienees Hefei 230026 University of Science and Technology of China 

出 版 物：《Progress in Natural Science:Materials International》 (自然科学进展·国际材料(英文))

年 卷 期：1998年第1期

页      面：99-106页

学科分类：070902[理学-地球化学] 0709[理学-地质学] 07[理学] 

基　　金：Project supported by the National Natural Science Foundation of China and the Chinese Academy of Sceinces 

主　　题：oxygen isotopes quartz veins fluid flow eclogitization metamorphism Sulu terrane. 

摘      要：The oxygen isotope study has been carried out for quartz-veins within eclogrte and associated gneiss from the Donghai district in the western part of the Sulu terrane, eastern China. Oxygen isotope equilibrium has been achieved between quartz and other minerals, yielding the isotope temperatures of 660-840℃ for quartz veins, 595-725℃ for eclogites, and 505-665℃ for gneiss δ18O values of vein-quartz vary from - 5.3‰ to + 7 5‰, but resemble δ 18O values of host eclogites, indicating a close approach of isotopic equilibrium between metamorphre fluids and the host rocks. An interally buffered fluid flow is implicated during ultrahigh-pressure metamorphism and subsequent retrogression. The fluid would be produced by dehydration of hydrothermally altered eclogite precursors and thus Us δ18O values were governed by the nature of host eclogites. These provide evidence for the fracture flow of meta-morphic fluid during eclogitization.