The Narrative of Quartz and Silica in the Earth and Other Planetary Bodies

Quartz and other silica minerals are amongst the most important constituents of the Earth’s crust, both as rock-forming mineral components and as tools for understanding Earth processes. Quartz and other forms of silica are essential parts of both the geological and biochemical cycles with the potential to help us understand the processes of our planet across disciplines. This article is a narrative of quartz, starting with its crystallization from fractionated, silica-rich magmas, transport, and deposition of silica by hydro- thermal fluids, as well as physical, chemical, and biogenic processes resulting in silica weathering, transport, accumulation, and the formation of sedimentary silica deposits. Extraterrestrial quartz and silica occurrences are also discussed.

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December 2025 --The Variscan Orogeny in Europe – Understanding Supercontinent Formation

The Variscan orogen formed between 380 and 300 million years ago through several accretionary and collisional cycles, culminating with the construction of the Pangea supercontinent. This process occurred via sequential opening and closure of oceanic basins, synchronous detachment of Gondwana derived continental ribbons, and their outboard amalgamation onto the Laurussia margin. The Variscan orogen is rather unique compared with other orogenic belts on Earth: its overthickened and dominantly magmatic crust in the central belt, surprisingly minor mantle involvement in the magmatic and geodynamic processes, coherent and pulsed magmatism along the collision suture, and its complex accretionary history. Because its final product, Pangea, is the youngest and best-understood supercontinent on Earth, the Variscan orogeny offers clues for understanding the mechanisms of supercontinent formation.