Unusual high-density and saline aqueous inclusions in ultrahigh pressure metamor- phic rocks from Sulu terrane in eastern China  

作　　者：SHEN Kun ZHANG Zeming A.M.van den Kerkhof XIAO Yilin XU Zhiqin J.Hoefs 

机构地区：[1]Institute of Geological Sciences of Shandong,Jinan 250013,China [2]Institute of Geology,CAGS,Beijing 100037,China [3]Geoscience Center,University Gttingen,Gttingen 37077,Germany

出　　处：《Chinese Science Bulletin》2003年第18期2018-2023,共6页

摘　　要：Primary high-density fluid inclusions were identified in garnet from ultrahigh pressure eclogite in the southern part of the Sulu terrane. They occur isolatedly or in cluster together with relatively low-density two-phase inclu-sions. The eutectic temperature of the inclusions is as low as ≤ -52℃. A bubble was nucleated in a liquid inclusion dur-ing the specific stage of cyclic cooling-heating runs, and the liquid-gas homogenization temperature was measured to be ≤-12.5℃. The composition of the inclusions modeled by the system CaCl2-NaCl-H2O, yields the fluid density of 1.27g/cm3 that corresponds to a pressure of ca. 2.4 GPa at thetemperature of peak eclogite-facies metamorphism, close tothe ultrahigh pressure metamorphic conditions. During theexhumation of the eclogite the inclusions reacted with thehost mineral, forming hydrous silicate minerals that resulted in lowering of the fluid density and its transformation to multi-phase inclusions.Primary high-density fluid inclusions were identified in garnet from ultrahigh pressure eclogite in the southern part of the Sulu terrane. They occur isolatedly or in cluster together with relatively low-density two-phase inclusions. The eutectic temperature of the inclusions is as low as ≤52°C. A bubble was nucleated in a liquid inclusion during the specific stage of cyclic cooling-heating runs, and the liquid-gas homogenization temperature was measured to be ≤12.5°C. The composition of the inclusions modeled by the system CaCl2-NaCl-H2O, yields the fluid density of 1.27 g/cm that corresponds to a pressure of ca. 2.4 GPa at the temperature of peak eclogite-facies metamorphism, close to the ultrahigh pressure metamorphic conditions. During the exhumation of the eclogite the inclusions reacted with the host mineral, forming hydrous silicate minerals that resulted in lowering of the fluid density and its transformation to multi-phase inclusions.

关 键 词：ultrahigh pressure ECLOGITE fluid inclusion microther-mometry ISOCHORE P-T path. 

分 类 号：P588.12[天文地球—岩石学]