The Lacustrine Fossiliferous Deposits of the Las Hoyas Subbasin (Lower Cretaceous, Serranía de Cuenca, Iberian Ranges, Spain)

Resumen

The Las Hoyas subbasin is located in the Serranía de Cuenca (southwestern Iberian ranges, east-central Spain) (Figure 1). Its sedimentary record is entirely composed of upper Barremian continental deposits that belong to the La Huerguina Formation (Vilas et al.,1982). It is a half-graben basin (Figures 1-3) that resulted from a period of rifting during the Early Cretaceous that divided the southwestern Iberian Basin into many small subbasins with differential subsidence rates (Vilas et al., 1983; Salas and Casas, 1993;Soria et al., this volume). The climate during the Barremian in this area was subtropical with alternating rainy and dry seasons (Ziegler et al., 1987; Gierlowski-Kordesch et al., 1991).The Las Hoyas subbasin contains the thicke strecord of continental deposits of the La Huerguina Formation in the Serranía de Cuenca basin (Melendezet al., 1994). Three different lacustrine fossiliferous lithosomes are identified throughout the stratigraphicsuccession of the Las Hoyas subbasin (Figure 3). Eachone of those lithosomes is considered to be a KonservatLagerstiitte and has yielded a rich and exceptionally well-preserved assemblage of terrestrial and fresh water flora and fauna (Table 1). The main preservational features of the association are the high density of remains, preservation of soft tissues, high degree of articulation, and skeletal integrity.