PALYNOSTRATIGRAPHY OF THE MUFARA FORMATION (MIDDLE-UPPER TRIASSIC, SICILY)

Abstract

The study of 10 sections of the Mufara Formation in northern Sicily yielded four palynomorph associations ranging in age from late Ladinian/early Carnian to late Carnian, and identified a trend in the compositional evolution of the assemblages within the Camerosporites secatus phase. The primary goal of this study was to create a composite section of the Mufara Formation, giving a tentative stratigraphic order to the 10 investigated successions on the basis of palynomorphs range intervals. The oldest assemblage (A) is dominated by long-ranging bisaccates but is characterised by the presence of transitional Ladinian-Carnian taxa such as Foveosporites visscheri, Gordonispora fossulata, Sellaspora rugoverrucata, Weylandites magmus and Enzonalasporites vigens, and by the incoming  of the first Carnian elements, Patinasporites densus and Vallasporites ignacii. Assemblage A is distinguished from the younger ones (B-D) by the absence of Camerosporites secatus. Assemblage B includes taxa which are present also in assemblage A (P. densus, V. ignacii, E. vigens, Praecirculina granifer and Partitisporites novimundanus). Camerosporites secatus, Aratrisporites tenuispinosus, Kyrtomisporis ervii and Striatoabieites aytugii occur for the first time and, with  the last occurrences of  F. visscheri, G. fossulata and S. rugoverrucata, indicate that this assemblage is of Cordevolian-early Julian age. Assemblage (C) comprises an association of Camerosporites  secatus, Patinasporites densus, Enzonalasporites  vigens, Vallasporites  ignacii, Praecirculina granifer, and Duplicisporites granulatus, and taxa with LADs (Last Appearance Datum) in the Julian and the early Tuvalian (P. novimundanus and Lagenella martinii respectively). This assemblage may be interpreted as transitional between assemblage B and D. Assemblage D comprises a typical Carnian association of Camerosporites  secatus, Patinasporites densus, Enzonalasporites  vigens and Vallasporites  ignacii, and includes the first occurrences of Partitisporites quadruplicis and Samaropollenites speciosus, which indicate a Tuvalian substage (late Carnian) age.