The question what drives tectonic plates has been around since plate tectonics was first developed. In principle, the fluid dynamics is well-known but what is not well known are the material properties, especially mantle viscosity structure which determines how much force is needed to pull a plate with a certain speed, but also how fast …[Read More]
Geomythology is a relatively recent term, coined by Dorothy B. Vitaliano in 1966. It represented the birth of what will become a new multidisciplinary approach, aimed not only at explaining the geological meaning of natural phenomenon behind long-told folklore (myths and legends), but also at bridging the communication gap between scientists and non-scientists (Vitaliano, 1973). …[Read More]
As readers of this blog know, geology is an awe-inspiring subject, dealing as it does with immensely powerful forces operating on time scales, pressures, and temperatures we can barely fathom. It is geological processes that are responsible for the continents, oceans, mountain ranges, indeed for all the landscapes we see around us. Even though many …[Read More]
This edition of ‘Features from the field’ is brought to you by Faris Beg, a masters student on the EU Erasmus Mundus Joint Master’s program in planetary geosciences—GeoPlaNet. This blog is a result of a geological field excursion carried out collectively in groups by students, organized by the GeoPlaNet consortium in Alcañiz, Spain. He will …[Read More]
Volcanoes are everywhere along plate margins and on hot spots on the planet’s surface. Just in the past 2 years, we have witnessed enormous explosive eruptions such as that of the Hunga Tonga volcano which released an amount of energy equivalent to hundreds of atomic bombs, and massive lava flows, as at the Cumbre Vieja …[Read More]
Shear zones are areas of intense deformation that localize the movement of one block of the crust with respect to another. In previous posts, we have seen that shear zones contain some very deformed rocks called mylonites, lineations that tell us the direction of movement, and useful kinematic indicators, such as S-C fabrics, that allow …[Read More]
Deep beneath our feet, deformation of rocks at high temperature produces impressive structures such as shear zones, that localize the movement of two volumes of rock with respect to one another. Shear zones are strongly deformed bands with strongly foliated structures (i.e., with rocks that look like a pile of leaves) and kinematic indicators, such …[Read More]
The San Andreas Fault in California, the Alpine Fault in New Zealand, or the Main Frontal Thrust in the Himalayas are some of the most famous and largest fault zones that accommodate the relative displacement between two adjacent crustal blocks. Such faults, however, represent only the shallower expression of something much bigger: a crustal shear …[Read More]
This edition of “Beyond Tectonics” is brought to you by Dr. Derya Gürer and Luca Magri. Derya is a Lecturer in Earth Sciences at The University of Queensland in Brisbane, and Adjunct Lecturer at the University of Tasmania, and Luca is a PhD student at the University of Tasmania in Hobart, Australia. In early 2020, …[Read More]
An angular unconformity is an erosional surface that truncates older, tilted sedimentary layers and that is overlain by younger layers, oriented parallel to the unconformity. The discovery and interpretation of angular unconformities, like the famous Hutton’s unconformity at Siccar Point, Scotland, marked a paradigm shift in the geological theories of the 18th century. At that …[Read More]
