The chemical and mineralogical composition, structure and petrophysical properties of volcanic rocks, composing three Quaternary volcanoes of Spitsbergen island - Sverrefjellet, Halvdanpiggen and Sigurdfjellet - have been ...
Since Early Precambrian volcanic rocks are typically strongly altered by superimposed processes, they retain primary composition and texture only in exceptional cases. Such a case is observed in the Early Paleoproterozoic ...