Paleontología y bioestratigrafía (micromamíferos) del Mioceno medio y superior del Sector Central de la Cuenca del Duero

Abstract

In the central area of the Duero Basin, 14 micromammal associations have been selected over a total of 80 fossil bearing localities, and a 4-biozone sequence has been established for the Middle-Late Miocene transit, on a sedimentary sequence about 200 m thick. The four assemblage zones are:a) at the bottom, the Megacricetodon lopezae zone. This zone also contains M.minor, M. crusafonti, Peridyromys rex, Chalicomys jaegeri and Prolagus major, b) the Megacricetodon ibericus zone. Other taxa present in this zone are Microdyromys koenigswaldi and Ramys perezi.c) the Cricetulodon hartenbergeri zone. It also contains Megacricetodon freudenthali, Ramys perezi and Eomyops catalaunicus. Progonomys hispanicus is present in small number.d) the Progonomys hispanicus zone. This zone also contains Myolidus sinuosus, Ramys cf. multicrestatus and Rotundomys montisrotundi The biozonation of the Duero Basin (Castilla) has been correlated with that of the Calatayud-Daroca Basin (Aragón) and that of the Vallés-Penedés Basin (Cataluña).A general biochronological sequence results for this period in Spain, which may be extended to other mediterranean regions. The use of biochronological markers is discussed. The correlation of biosequences and the establishment of a more general chronostratigraphy based on tecto-sedimentary ruptures is proposed.