A fern-bennettitalean floral assemblage in Tithonian- Berriasian travertine deposits (Aguilar Formation, Burgos- Palencia, N Spain) and its palaeoclimatic and vegetational implications

摘要

This report describes a macrofloral fossil assemblage discovered in travertine deposits of the Tithonian-Berriasian Aguilar Formation (provinces of Palencia and Burgos, N Spain). The assemblage includes megaremains of a single species of Filicales (Cladophlebis denticulata) and of eleven taxa tentatively identified as Bennettitales (Otozamites mundae, Otozamites sp., Ptilophyllum pecten, Ptilophyllum pectiniformis, Ptilophyllum sp. cf. pectiniformis, Ptilophyllum acutifolium, Ptilophyllum sp., Pterophyllum cycadites, Pterophyllum sp. cf. thomasii, Zamites pumilio, and cf. Pseudocycas sp.). Specimens were preserved as impressions coated with a microbial film up to 5 mm thick made up of: bacteria and cyanobacteria. Based on the available sedimentological and palaeobotanical data, a dry-savannah vegetation and an arid climate were deduced. Late Jurassic macrofloras are globally scarce and have not previously been reported in Spain. Hence, the Aguilar Formation macroflora provides valuable information on the coeval phytogeography and palaeoclimate of southwestern Europe. Furthermore, the lack of floras observed so far in palaeotravertine deposits older than Pliocene in age makes this macroflora exceptional.