Interevaporitic deposits of Las Minas Gypsum Unit: A record of Late Tortonian marine incursions and dolomite precipitation in Las Minas Basin (eastern Betic Cordillera, SE Spain)

Autor: Ariana Carrazana, Jesús M. Soria, Luis Gibert, Victoriano Pineda, Mónica Sánchez-Román, Jordi Ibáñez-Insa
Přispěvatelé: Universidad de Alicante. Departamento de Ciencias de la Tierra y del Medio Ambiente, Cambios Paleoambientales, Ministerio de Economía y Competitividad (España), Generalitat de Catalunya, Ibáñez Insa, Jordi, Geology and Geochemistry, Ibáñez Insa, Jordi [0000-0002-8909-6541]
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Palaeogeography, Palaeoclimatology, Palaeoecology, 564:110171, 1-18. Elsevier
Digital.CSIC. Repositorio Institucional del CSIC
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Digital.CSIC: Repositorio Institucional del CSIC
Consejo Superior de Investigaciones Científicas (CSIC)
Pineda, V, Gibert, L, Soria, J M, Carrazana, A, Ibáñez-Insa, J & Sánchez-Román, M 2021, ' Interevaporitic deposits of Las Minas Gypsum Unit : A record of Late Tortonian marine incursions and dolomite precipitation in Las Minas Basin (eastern Betic Cordillera, SE Spain) ', Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 564, 110171, pp. 1-18 . https://doi.org/10.1016/j.palaeo.2020.110171
ISSN: 0031-0182
Popis: The Las Minas Gypsum Unit consists of more than 100 m of alternations of gypsum, carbonates and marls in Las Minas Basin (Betic Cordillera). Although this unit has been previously described as lacustrine, a marine influence in the basin has been suggested. This study provides new geochemical and paleontological data supporting the marine influence during the interevaporitic episodes, allowing to refine the palaeogeography of the eastern Betic Seaway during the Late Tortonian. Sr-87/Sr-86 ratios in gypsum (0.70797 to 0.70825) suggest recycling of Triassic evaporites. The sulphate isotopic values in gypsum (11.5 < delta S-34(VCDT) < 21.9 parts per thousand; 16.6 < delta O-18(VSMOW) < 28.1 parts per thousand) are indicative of microbial sulfate-reduction activity. Carbonates are mainly composed of dolomite formed by subspherical crystal aggregates related to bio-mediated processes. The Sr-87/Sr-86 values in the interevaporitic carbonates (0.70823 to 0.70851) are higher than those expected for Triassic marine authigenic carbonates but lower than expected for the Late Miocene ones, suggesting a mixing of continental and marine water contributions. The 'non-marine' isotopic values in gypsum and carbonates contrast with an abundant content of marine siliceous fossils (radiolarians, diatoms, porifera, etc.) in the marls and carbonates that reveals marine incursions into the basin between periods of gypsum precipitation. A tephra layer identified in Las Minas and in the nearby El Cenajo Basin, located in a more inland position, allows a precise correlation between both basins, showing marine fossils in Las Minas and lacustrine in El Cenajo. In El Cenajo Basin, marine microfossils have been found but only in some levels, while others show lacustrine diatoms. A new palaeogeographic model of evaporitic lakes with temporal marine connections is proposed for the latest Tortonian in this region, when the uplift of the Betic Cordillera was very active accelerating the palaeogeographic evolution.
Funding was provided by Spanish Government grants CGL-2013-42689 and CGL-2016-79458, and by the Catalan Government action 217-SGR-829.
Databáze: OpenAIRE
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