Palinología del Turoniense en el Sinclinorio de Campisábalos: aportaciones al análisis estratigráfico secuencial (Sistema Central-Cordillera Ibérica; Guadalajara-Segovia, España)

Abstract

The palynological analysis of several clayey and marly levels in the upper part of Picofrentes Formation, Alcorlo Bed and the lower part of the Embalse de la Tranquera Formation in two stratigraphic sections (Somolinos and Grado de Pico) in the synclinorium of Campisábalos (Iberian Range - Central System) allows to recognize the general sedimentary trend of the studied succession from neritic, platform environments to coastal and lagoonal ones, grading further upwards to clear continental events (complete absence of marine and brackish-water palynomorphs). Finally, at the top of the succession a major change in the sedimentary trend to proximal marine environments is again observed. The presence of three 4th order parasequence sets is observed. The two basal ones with an overall regressive trend, belonging to a 3rd order sequence and having a mid Turonian age according to the presence of the form genus Trudopollis. The existence of a lowstand sand body with pollen mainly continental, corresponds to a third 4th order parasequence set that is linked to the base of the overlying 3rd order sequence. That sandy lowstand body represents a major drop in the relative sea-level, developing a 2nd order megasequence boundary in the Iberian Basin; the age of this upper 4th order parasequence set is upper Turonian due to the presence of Vacuopollis pollen grains.