Strontium-isotope stratigraphy of the Aptian-Albian transition in the western Maestrat Basin (E Iberia)
Bover-Arnal, Telm (Universitat de Barcelona)
Moreno Bedmar, Josep Anton (Universidad Nacional Autónoma de México)
Salas, Ramon (Universitat de Barcelona)
Pascual-Cebrian, Enric (Universitat de Barcelona)

Date:	2025
Abstract:	The Aptian-Albian transition in the Maestrat Basin (E Iberian Chain) encompasses two lithostratigraphic units: Benassal and Escucha. In some sectors of the basin, such as the western Galve and Las Parras sub-basins, this stratigraphic interval recorded a progressive shift from widespread carbonate platform settings to coastal siliciclastic-influenced and coal-bearing environments. Due to the transitional nature of this interval, establishing a clear stratigraphic boundary between the upper part of the Benassal Formation and the lower part of the Escucha Formation is challenging. Additionally, there is no unanimous agreement on the age range of these formations. To shed light on the stratigraphic location of the boundary between the Aptian and the Albian, strontium-isotope analyses were carried out on thirteen low-Mg calcite oyster shells to derive numerical ages. In Las Parras Sub-basin, the 87Sr/86Sr values obtained from the siliciclastic-influenced transitional deposits between the Benassal and Escucha formations, as well as from the lowermost part of the Escucha Formation, range from 0. 707282  0. 000002 to 0. 707410  0. 000002. These Sr-isotope ratios translate into numerical ages that constrain this stratigraphic interval to the early Albian. The oyster shells collected in the Galve Sub-basin exhibit a higher degree of diagenetic alteration. Nevertheless, the least altered specimens analysed from the lower part of the transitional facies between the Benassal and Escucha formations in this latter sub-basin yielded Sr-isotope ratios between 0. 707197 ± 0. 000003 and 0. 707256 ± 0. 000002. These values correspond to ages spanning from the latest Aptian to the earliest Albian. Accordingly, in most sectors of the western Maestrat Basin, the Aptian-Albian boundary is likely to be stratigraphically located at the lowermost part of the transitional facies between the Benassal and Escucha formations.
Grants:	Ministerio de Ciencia, Innovación y Universidades PID2024-159218NB-I00 Agencia Estatal de Investigación PID2020-113912GB-I00
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Strontium-isotope stratigraphy ; Geochronology ; Escucha formation ; Early cretaceous ; Iberian chain
Published in:	Geologica acta, Vol. 23 (2025) (Carbonate successions from Iberia and the Caribbean - Homage to Ramon Salas) , ISSN 1696-5728

Adreça original: https://revistes.ub.edu/index.php/GEOACTA/article/view/50612
Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/980000002244

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