Interplay of caldera and tectonic subsidence in an inverted Late Carboniferous–Permian basin (Central Pyrenees)

Simón-Muzás, Ana ; Soto, Ruth ; García-Lasanta, Cristina ; Housen, Bernard ; Gisbert, Josep (Universidad de Zaragoza) ; Casas-Sainz, Antonio (Universidad de Zaragoza)

Resumen: Deposits of thick volcanic and volcaniclastic series can be interpreted as either related to regional tectonics (commonly extensional or transtensional tectonics) or local volcanic mechanisms (caldera collapse). In order to distinguish between these two end-member mechanisms, we propose the use of magnetic techniques, namely analysis of Anisotropy of Magnetic Susceptibility (AMS) and paleomagnetism, and analysis of geological structures. These techniques have been applied to the Estac Basin (Central Pyrenees), an inverted Late Carboniferous–Permian basin now involved in the antiformal stack of the Pyrenean belt. AMS data provide directions of flow of volcanic rocks that can be interpreted in terms of palaeo-slopes and therefore can be related to structures contemporary with deposition and Late Carboniferous–Permian volcanic activity. The maximum of the magnetic lineation (i.e. volcanic paleoflow) direction is bimodal, with (i) an absolute maximum (as occurring in most South-Pyrenean Late Carboniferous–Permian basins) along a WNW–ESE direction and (ii) a secondary magnetic lineation along an N–S direction. Paleomagnetic data obtained from the volcanic products show a primary magnetization or early remagnetization compatible with the Late Carboniferous–Permian paleomagnetic reference direction and allow us to reconstruct an early folding probably related to the warping of the basin. The magnetic and structural data can be interpreted according to a volcano-tectonic subsidence model in which E–W faults played a major role and caldera collapse contributed to the important thickness of the volcaniclastic deposits.

Idioma: Inglés

DOI: 10.1017/S0016756825100514

Año: 2026

Publicado en: GEOLOGICAL MAGAZINE 163 (2026), [24 pp.]
ISSN: 0016-7568

Financiación: info:eu-repo/grantAgreement/ES/MICINN/FPU19-02353
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2019-108753GB-C22
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2020-114273GB-C22

Tipo y forma: Article (Published version)

Área (Departamento): Área Petrología y Geoquímica (Dpto. Ciencias de la Tierra)
Área (Departamento): Área Geodinámica Interna (Dpto. Ciencias de la Tierra)