Clay mineralogy in southeast Spain during the late Miocene: climatic, paleoceanographic and tectonic events in the Eastern Betic seaway

Abstract

X-ray diffraction and electron microscope investigations were performed on late Miocene sediments of the Fortuna Basin. Results were compared to available paleogeographic data and were interpreted in terms of terrigenous sources, climate, tectonics and sea level changes. Biostratigraphic and chronologic data allow the use of clay stratigraphy in providing paleoenvironmental information. The Western Mediterranean domain was subject to periods of strong aridification as early as late Tortonian. On the land climate was dominated by subarid conditions, favouring the development of pedogenic smectites and probably palygorskite. Tectonic activity rejuvenated the region episodically, especially after the Tortonian-Messinian boundary (lower Sanel marls), at the beginning of upper evaporites deposition (marine marl/gypsum alternations of the Rambla Salada Formation), and probably when the intra-Messinian inundation started. The sea level changes appear to have been of little importance in controlling the clay sedimentation patterns in the Eastern Betic seaway during late Miocene times.