Experimental studies show that K replacement of Na in triclinic plagioclase under hydrothermal conditions results directly in triclinic microcline without forming intermediate monoclinic orthoclase. These experiments bring laboratory and field evidence into agreement for the K-metasomatic origin of granites which contain exclusively microcline as the potash feldspar. Such replacements of a more...

Article history: Received 29 March 2017 Accepted 27 July 2017 Available online 04 August 2017 Subduction and collision are the key processes triggering geochemical refertilization of the lithospheric mantle beneath cratons. However, the way that the subducted plate influences the cratonic lithospheric mantle remains unclear. Here, in-situ major and trace-element and Sr isotopic compositions of ...

The Isua greenstone belt (Fig. 1) contains the oldest known, relatively well preserved, metavolcanic and metasedimentary rocks on Earth. The rocks are all deformed and many were substantially altered by metasomatism, but both the deformation and metasomatism were heterogeneous. Transitional stages can be seen from relatively well preserved primary volcanic and sedimentary structures to schists ...

Quantifying water contents in the lithospheric mantle is key to our understanding of global geodynamics, composition, and related physical properties. Most lithologies (peridotite) contain little (~50 ppm), but petrological heterogeneities such as pyroxenites are more hydrous (~300 ppm) relative rocks. Pyroxenites also melt at lower temperatures than peridotites thus important magma genesis. Th...

Abstract Hydration, carbonation, and related metasomatism of mantle peridotite play a significant role in the global geochemical cycle. In this study, we combined an analysis carbonated serpentinite with hydrothermal experiments on carbonation Ca-metasomatism for samples from Manlay ophiolite, southern Mongolia to investigate that mechanism body after serpentinization. Samples show was either t...