Aragonian stratigraphy reconsidered, and a re-evaluation of the middle Miocene mammal biochronology in Europe

The recently collected fauna of Armantes 1A in Chron C5Br of the Armantes s ection necessitates reinterpretation of the previous bio- and magnetostrati graphical correlations between the Armantes and Vargas sections (Calatayud- Daroca Basin, Central Spain) [W. Krijgsman, M. Garces, C.G. Langereis, R. D aams, J, van Dam, A.J. van der Meulen, J. Agusti, L. Cabrera, A new chronol ogy for the Middle to Late Miocene continental record in Spain, Earth Plane t. Sci. Lett, 142 (1996) 367-380]. The long reversal in the Vargas section is now correlated to C5Br, instead of to C5Cr, on the basis of the biostrat igraphical correlation of Armantes 1A to the faunas of Fuente Sierra 2 and 3 (in the Vargas section), which are situated in the basal part of the Midd le Aragonian (MN5). This leads to the revised age of 16.0 Ma fur the Early- Middle Aragonian (MN 4/5) boundary. Our age estimate of the MN5/6 boundary is maintained at ca. 13.75 Ma. The Vargas section is now considered to star t in Chron C5Cn.2r and to end in CSBn.1n. As a result of the revised correl ation the duration of the time gap between the fossiliferous parts of Varga s and the younger Aragon section, previously estimated as ca. 1.5 Myr, is n ow reduced to less than 200,000 years, The tie points of the European mamma l units (MN4-MN6) to the geomagnetic polarity time scale [F.F. Steininger, WA. Berggren, D.V. Kent, R.L. Bernor, S. Sen, J. Agusti, Circum-Mediterrane an Neogene (Miocene and Pliocene) marine-continental chronologic correlatio ns of European mammal units, in: R.L Bernor, V. Fahlbusch, H.-W. Mittmann ( Eds.), The Evolution of Western Eurasian Neogene Mammal Faunas, Columbia Un iv. Press, New York, 1996, pp. 7-46] are evaluated. Our age estimates of th e MN4/5 and MN5/6 boundaries are compatible with the new magnetostratigraph ic calibration of middle Miocene mammal zones in the Swiss Molasse basin [O . Kempf, T. Bolliger, D. Kalin, B. Engesser, A. Matter, New magnetostratigr aphic calibration of Early to Middle Miocene mammal biozones of the North A lpine foreland basin, in: J.-P. Aguilar, S, Legendre, J. Michaux (Eds.), Ac tes du Congres BioohroM '97, Mem. Trav. E.P.H.E. 21 (1997) 547-562]. (C) 19 99 Elsevier Science B.V, All rights reserved.