Plate tectonics is the unifying theory of the solid Earth that describes the surface of our planet as being fragmented into rigid plates that move in relation to each other. Many fundamental geological processes, such as earthquakes, volcanism, and the formation of mountains, occur at the plates’ boundaries. In its initial formulation, plate tectonics was a kinematic theory that described and quantified these movements and associated deformation. Plate tectonics evolved into a dynamic theory, describing the forces driving the surface deformation and the internal dynamics of our planet. We also came to realize that plate tectonics is only one of the possible tectono-magmatic styles in which a planet can operate and that these can change over time. In the past years, the geosciences community has started to develop a theory that integrates plate tectonics and mantle convection as part of a single system. This was possible because of the ever-increasing high-quality imaging of Earth’s interior and our computational capabilities. But while the progress has been enormous, there are still many uncertainties and challenges ahead. <...>

Crinoids are widespread in the Upper Carboniferous deposits of the central European Russia, being an important element of the benthic communities; nevertheless, they are extremely poorly understood. Better studied are the Middle-Late Carboniferous crinoids of this region. Nevertheless, their sampled remains are only partially described; the number of species and genera to be described is approximately the same as the number of previously described taxa; and the discovery of many new forms is not inconceivable. Such poor knowledge of these fossils is attributable to the very limited number of specialists, insufficient state of collections, and poor study of sampled remains. In the former USSR, the last four decades were marked by an enhanced interest to columns of extinct crinoids because they are most widespread amid crinoid remains. Nevertheless, they are almost completely ignored in the last years. Moreover, the researchers who studied columns of Ordovician, Silurian, Devonian, and, partly, Early Carboniferous crinoids did not pay attention to the Carboniferous deposits of the Russian Platform. <...>

The guy on the other end of the phone was offering me a job! A British government funded contract to work in the Geological Survey of Sierra Leone. As a fresh graduate this was an exciting prospect – a whole unexplored Archaean craton at my feet. The next three and a half years were an exciting time. It was the early 1970s when important new discoveries were being made in Archaean rocks in South Africa and the novel ideas of plate tectonics were still being newly applied to early Earth history. My position as a survey geologist provided me with the opportunity to map several greenstone belts and what seemed like an endless tract of granite gneisses and at the same time apply these new ideas in what appeared to be virgin territory. These were ‘formative’ years which cemented my fascination with the Archaean, an absorption which has remained with me over subsequent decades. <...>

Early Precambrian eclogites are widespread in the Belomorian Province of the Fennoscandian shield. There are three points of view on the their age: 1) Archean and Paleoproterozoic; 2) solely Mesoarchean; 3) solely Paleoproterozoic. The goal of this field trip is to show all these types of eclogites including Archean and Paleoproterozoic (from the authors' point of view) eclogites, eclogitized Paleoproterozoic coronitic gabbroids, Archean zoisitites and their structural position in the Gridino, Salma (Uzkaya Salma and Shirokaya Salma) and Kuru-Vaara areas of the Belomorian Province. The geological excursions provide a good opportunity for the participants and the reader to exanimate these contradicting points of view immediately at beautiful outcrops on islands of the White Sea, on the benches of the Kuru-Vaara quarry and in the walls of road pits in the Salma area.
This Field Guidebook is of interest for geologists, petrologists and geochronologists who study the early evolution of the Earth and HP-UHP metamorphic processes.