Fluid Evolution during HP and UHP Metamorphism in Dabie Shan, China: Constraints from Mineral Chemistry, Fluid Inclusions and Stable Isotopes   总被引：23，自引：1，他引：23  

XIAO  YILIN; HOEFS  JOCHEN; VAN DEN KERKHOF  ALFONS M.; SIMON  KLAUS; FIEBIG  JENS; ZHENG  YONG-FEI 《Journal of Petrology》2002,43(8):1505-1527

The Dabie Shan ultrahigh-pressure (UHP) metamorphic terraneis located in the eastern part of the east–west-strikingQinling–Dabie orogenic belt in China. A major mylonitizedcontact zone of 200–300 m width divides Dabie Shan intothe South Dabie Terrane (SDT) and the North Dabie Complex (NDC).Combined investigation of major and trace element geochemistry,fluid inclusions, and oxygen and hydrogen isotopes constrainsthe fluid history during the metamorphic evolution of the twometamorphic belts, which differ in their fluid and metamorphicevolution. Fluid inclusions in rocks from the SDT are mainlyaqueous with varying salinities, whereas those from the NDCare dominated by CO₂. Low  相似文献   

Fenitizing Processes Induced by Ferrocarbonatite Magmatism at Swartbooisdrif, NW Namibia   总被引：1，自引：0，他引：1  

DRUPPEL  KIRSTEN; HOEFS  JOCHEN; OKRUSCH  MARTIN 《Journal of Petrology》2005,46(2):377-406

The southeastern margin of the anorthositic Kunene IntrusiveComplex, NW Namibia, has been subsequently invaded by Mesoproterozoicsyenite, nepheline syenite and ferrocarbonatite dykes alongNE- and SE-trending faults. The first generation of carbonatiteintrusions frequently contains fenitized anorthositic wall-rockfragments set in a ferrocarbonatite matrix; later, subordinateveins of massive ferrocarbonatite are almost xenolith-free andcut through the main carbonatite dykes. A mantle source forboth carbonatite generations is constrained by their respectiveoxygen and carbon isotope compositions of ankerite (¹⁸O_SMOW8·91–9·73; ¹³C_PDB –6·98 to–6·76). Na-rich fluids, released from the meltparental to the ferrocarbonatites, caused the fenitization ofboth the incorporated anorthosite xenoliths and the borderinganorthosite, syenite and nepheline syenite. This process ismainly characterized by the progressive transformation of Ca-richplagioclase, K-feldspar and nepheline into albite and/or sodalite.The changing mineral modes indicate that the fenitizing fluidswere sodium-rich and strongly Si-deficient solutions, whichalso contained significant amounts of Sr, Ba, Nb and the lightrare earth elements. On the basis of mineral equilibria studies,it is possible to reconstruct the temperature conditions forcarbonatite emplacement (c. 830 ± 200°C) and recrystallization(c. 480 ± 130°C), and for the metasomatic formationof sodalite (c. 700 ± 70°C). KEY WORDS: anorthosite; fenitization; ferrocarbonatite; sodalite; stable isotopes  相似文献