![\"\"](\"https:\/\/anr-cmio.gm.umontpellier.fr\/wp-content\/uploads\/2024\/12\/Capture-decran-2024-12-17-a-10.06.07\u202fPM-300x300.png\")
This study sheds light on how valuable metals like lead (Pb), zinc (Zn), and silver (Ag) and associated critical metals formed in the Western Alps, a mountain range shaped by millions of years of geological activity. Using advanced techniques, we uncovered the processes behind these mineral deposits, linking their formation to the dramatic tectonic forces that created the Alps.<\/p>\n
The research focused on metal-rich veins found in fault zones, areas where the Earth\u2019s crust cracked and shifted under immense pressure. These cracks acted like highways for hot, mineral-rich fluids circulating deep underground. When these fluids are expelled upward, variations in the fluids physiochemistry (like temperature, pressure andoxidoreduction conditions) lead to metals crystallization and formed deposits. The study identified two key periods of mineral formation 35\u201340 Ma and 15\u201320 Ma, associated with collision and exhumation of the Belledonne Alpine massif. These findings suggest that these metals are directly tied to the tectonic activity that shaped the region.<\/p>\n
To uncover this history, we used two state-of-the-art in situ dating methods: Rb\u2013Sr and U\u2013Th\u2013Pb isotope analysis. These techniques allow us to determine the age of tiny mineral grains with incredible precision. By combining the two methods, the team was able to confirm that the deposits are entirely of Alpine origin, with no signs of earlier formations. This is significant because it challenges previous theories suggesting that these metals might have come from older geological events.<\/p>\n
The cross-combination of the two in situ dating methods also revealed several different stages of mineralization or remobilization. For example, in some areas, the deposits showed signs of being remobilized\u2014essentially \u201crecycled\u201d as fault activity and fluids circulated again millions of years later. This highlights the dynamic nature of Earth\u2019s crust, where metals deposits are remobilized by geological processes especially during mountain-formation.<\/p>\n
Understanding how these deposits formed is not just important for science\u2014it has practical implications too. Knowing the conditions that create such metal deposits can guide the search for similar resources in other parts of the world. Lead, zinc, and silver and critical metals (like Ge, Ga, In) associated are essential for many technologies, from batteries to electronics, and finding new sources is crucial as demand increases.<\/p>\n
In summary, this research demonstrates how the forces that built the Alps also created and remobilized rich metal deposits by driving fluid circulation through deep faults. It paints a detailed picture of how these processes unfolded over millions of years, providing a new understanding of how mountain-building and metal formation are interconnected. Beyond its scientific contributions, this work offers valuable insights for exploring and managing Earth\u2019s natural resources.<\/p>\n
How to cite:<\/p>\n
Maxime Bertauts, <\/span>Adrien Vezinet, <\/span>Emilie Janots, <\/span>Magali Rossi, <\/span>Isabelle Duhamel-Achin, <\/span>Philippe Lach, <\/span>Pierre Lanari; Cenozoic Pb\u2013Zn\u2013Ag mineralization in the Western Alps. Geology<\/em> 2024;; 52 (5): 352\u2013356. doi: https:\/\/doi.org\/10.1130\/G51818.1<\/a><\/p>\n Fig. 1: Photos of the Alpine ore deposits area and outcrop.<\/p>\n Figure 2: Pb-Zn-Ag-Cu-Fe rock samples from Alpine deposits.<\/p>\n Figure 3: Thin sections of ore samples from Pb-Zn-Ag Alpine deposits.<\/p>\n","protected":false},"excerpt":{"rendered":" This study sheds light on how valuable metals like lead (Pb), zinc (Zn), and silver (Ag) and associated critical metals formed in the Western Alps, a mountain range shaped by millions of years of geological activity. Using advanced techniques, we … Continuer la lecture ![\"\"](\"https:\/\/anr-cmio.gm.umontpellier.fr\/wp-content\/uploads\/2024\/12\/Fig1_Photos-of-the-Alpine-ore-deposits-area-and-outcropV2-300x287.jpg\")
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