Paleogene evolution of the External Betic Zone and geodynamic implications

Authors

  • F. GUERRERA Dipartimento di Scienze della Terra, della Vita e dell’Ambiente (DiSTeVA), Università degli Studi di Urbino ‘‘Carlo Bo’’. Campus Scientifico E. Mattei, 61029 Urbino, Italy.
  • M. A. MANCHEÑO Departamento de Química Agrícola, Geología y Edafología, Facultad de Química, Universidad de Murcia. 30100 Murcia, Spain.
  • M. MARTÍN-MARTÍN Departamento de Ciencias de la Tierra y Medio Ambiente, Universidad de AlicanteCampus San Vicente, AP-99, 03080 Alicante, Spain
  • G. RAFFAELLI Dipartimento di Scienze della Terra, della Vita e dell’Ambiente (DiSTeVA), Università degli Studi di Urbino ‘‘Carlo Bo’’. Campus Scientifico E. Mattei, 61029 Urbino, Italy.
  • T. RODRÍGUEZ-ESTRELLA Departamento de Ingeniería Minera, Geologíca y Cartográfica, Universidad Politécnica de Cartagena. 30202 Cartagena Spain.
  • F. SERRANO Departamento de Ecología y Geología, Universidad de Málaga. Campus de Teatinos, 29071 Malaga, Spain.

Keywords:

Stratigraphy, Minero-petrography, Unconformities, Paleogeography, Geodynamic Evolution

Abstract

Interdisciplinary studies combining field data (geological and tectonic mapping, lithostratigraphic reconstructions, lithofacies characterization, correlations and sampling) and laboratory analyses (biostratigraphy, chronostratigraphy, clay mineralogy and sandstone petrography) of eight Senonian-Paleogene successions from the Sierra de La Pila and Sierra de El Carche areas (Murcia province, SE Spain) belonging to the External Betic Zone are presented. Field evidence of tectonic activity (slumps, olistostromes, syn-genetic folds, lateral variability, changes in thicknesses, para- and unconformity boundaries, stratigraphic gaps, shallowing upward trends to emersion, etc.) was found in several Paleogene intervals. The results enable a better reconstruction of the stratigraphic architecture and chronostratigraphy of the Paleogene record, highlighting in particular: facies evolution, discontinuities, depositional sequences (Middle-Upper Maastrichtian, Upper Paleocene-Middle Eocene, Oligocene-Lower Aquitanian), environmental evolution (homogeneous conditions during the Late Cretaceous and successive realm diversification from platform to slope to basin) and correlations, along the Prebetic to Subbetic transition, which is a key sector to understand the northeastward variations of the South Iberian margin. A conclusive paleogeographic and geodynamic evolutionary model for the study area is proposed, hypothesizing that Paleogene compressive tectonics affected the eastern External Betic Zone. In addition, correlations with successions from the western External Betic Zone evidenced asynchronous deformation from east to west along the internalmost External Betic Zone. Moreover, a comparison with the external Tunisian Tell enables the recognition of similar sedimentarytectonic events, imposing new constraints in the Paleogene geodynamic reconstruction throughout the western Tethys.

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Published

2014-07-31

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Articles