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 ...

Biodiversity is a complex subject, and its many facets are dealt with differently by different end users and interested parties. Noss' (1990) definition distinguishes between structural, functional and compositional diversity at levels of organisation ranging from genes, to species and populations, to communities, ecosystems and landscapes. This conceptual framework helps to be explicit about w...

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 ...