Middle Miocene foraminifera from Canals (Valencia, western Mediterranean). Biostratigraphic and palaeoenvironmental aspects

Abstract

The age and the palaeoenvironmental conditions of the tap marls outcroppings near the locality of Canals in the south of the Valencia Province (E Spain) are discussed. Based on the planktonic foraminifera assemblages, mainly the species Globorotalia praemenardii , these tap marls are dated as Serravallian in age (middle Miocene). The analysis of the foraminiferal assemblages suggests a relatively well-ventilated uppermiddle bathyal environment, with only a moderate oxygen deficiency throughout most of the studied section. The rather cool waters indicated by the planktonic foraminifera (e.g. Globigerina bulloides ) are compatible with the decreasing temperatures trend during the middle Miocene due to the extension of the Antarctic Ice Cap. The abundant diatoms and radiolaria, and the highly diverse benthic foraminiferal assemblages are also consistent with prevailing upwelling conditions and a high surface productivity and carbon flux. The apparent warming trend throughout the short section analysed, together with the sharp decrease in diversity and the rise of dysoxic species like Globobulimina affinis at the uppermost sample, might indicate either a short-term warming episode or a restriction of upwelling currents, eventually resulting in more sluggish bottom circulation and less well-oxygenated waters.