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Geochronology and geochemistry of the Gréixer rhyolitic caldera complex: Implications on Permo-Carboniferous magmatism (South-Central Pyrenees, NE Spain).
- Source :
-
Lithos . Apr2024, Vol. 470, pN.PAG-N.PAG. 1p. - Publication Year :
- 2024
-
Abstract
- The Gréixer Rhyolitic Complex is one of the most important manifestations of the post-Variscan Permo-Carboniferous volcanism of the Catalan Pyrenees. This volcanic complex is represented by a > 800 m thick, > 12 km wide, intra-caldera succession, mostly composed of strongly-welded, lava-like rheomorphic rhyolitic pyroclastic rocks. Previous studies have attributed a Lower Permian age to this caldera complex and interpreted it as having resulted from the gravitational collapse of a central volcanic edifice after a large-volume explosive event, mostly represented by widespread extra-caldera pyroclastic deposits (the Castellar de n'Hug Ignimbritic Member), which was radially emplaced from the caldera structure. However, new stratigraphic, structural, geochemical, and geochronological data reveal that this co-genetic relationship between the inferred intra- and extra-caldera deposits does not exist. On the contrary, each of these two successions of pyroclastic deposits resulted from a different volcanic event, which had occurred within a time span of 15 Ma. Moreover, the geochemical signature of these volcanic rocks shows a different magma source for each case, with a clear crustal origin for the Gréixer Rhyolitic Complex and a mixed mantle-crustal origin for the Castellar de n'Hug Ignimbrite Member. The apparent stratigraphic correlation between both successions is the result of the Alpine tectonics, which put together different late and post-Variscan Permo-Carboniferous rocks that had originated in different areas and at different times. • The Gréixer Rhyolitic Complex is distinctive geological element of the Pyrenees. • It corresponds to a rheomorphic rhyolitic pyroclastic rocks intra-caldera succession. • U-Th dating gave a Stephanian C age (303 Ma years, Gzhelian) for these rhyolitic rocks. • The Gréixer Rhyolitic Complex has a clear crustal signature. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00244937
- Volume :
- 470
- Database :
- Academic Search Index
- Journal :
- Lithos
- Publication Type :
- Academic Journal
- Accession number :
- 175960924
- Full Text :
- https://doi.org/10.1016/j.lithos.2024.107524