Presolar History Recorded in Extraterrestrial Materials

Extraterrestrial samples include a rich variety of materials with different histories. Among the array of Solar System materials are tiny grains with extremely anomalous isotopic compositions—records of nucleosynthetic processes that occurred deep within their now extinct parent stars. The isotopic and mineralogical characterization of these presolar grains in the laboratory provides unprecedented insight into stellar and galactic evolution, nucleosynthesis, and dust formation and processing. The discovery of presolar grains has opened up a pivotal new dimension in the field of astrophysics. Coupled with astronomical observations and astrophysical studies, stardust analyses bring nanometer-scale detail to the history of our immense Galaxy.

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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.