Late Early Miocene palaeoenvironmental changes in the North Alpine Foreland Basin Martina Pippèrr ⁎, Bettina Reichenbacher Department of Earth and Environmental Sciences, Palaeontology & Geobiology, Ludwig-Maximilians-University, Richard-Wagner-Straße 10, D-80333 Munich, Germany abstract article info Article history: Received 5 May 2016 Received in revised form 18 December 2016 Accepted 1 January 2017 Available online xxxx The North Alpine Foreland Basin (NAFB) experienced rapidly changing palaeoenvironmental conditions at the end of the Early Miocene (middle-to-late Burdigalian, Paratethys stages Ottnangian and Karpatian), with transformation of fully marine settings into brackish and eventually freshwater environments. These changes were related to global sea-level fluctuations, climate oscillations, and tectonic processes associated with the uplift of the Alps. This study presents a new and comprehensive data set, derived from 13 boreholes and 491 core samples from the Molasse Basin of southwest Germany, that provides a significantly better understanding of late Early Miocene palaeoenvironments in the NAFB. Based on lithostratigraphy, biostratigraphy, and palaeoecological interpretation of rich fauna and flora assemblages, we show that the upper Burdigalian sediments comprise a regressive lower seg- ment (Grimmelfingen Formation and equivalents), as indicated by the occurrence of the bivalve Rzehakia, and a transgressive upper component (Kirchberg Formation and equivalents) characterized by the advent of new fish and mollusc assemblages. Furthermore, we present a new lithostratigraphic concept for the Kirchberg Formation, which forms an important part of the Upper Brackish Molasse (OBM). Based on biostratigraphic constraints and re- cently published magnetostratigraphic data, it appears that the regressive segment of the upper Burdigalian OBM sediments correlates with the end of the global third-order sea-level cycle Bur 3, while the transgressive component reflects the Karpatian transgression at the beginning of sea-level cycle Bur 4. This implies that the Karpatian trans- gression actually affected the Molasse Basin of southern Germany and Upper Austria, whereas previous studies had considered this part of the NAFB as terrestrial during that time span. The new results are depicted in three palaeogeographic maps for the NAFB at 18 Ma, 17.5–17.1 Ma and 17 Ma, respectively. © 2017 Elsevier B.V. All rights reserved. Keywords: Western Paratethys Ottnangian Karpatian Rzehakia facies Stratigraphy Palaeogeography 1. Introduction The North Alpine Foreland Basin (NAFB, Fig. 1A), also referred to as Molasse Basin, formed in the Late Eocene/Early Oligocene and existed until the Late Miocene. It was part of the Western and Central Paratethys, which developed in the course of the Alpine orogeny through isolation from the northern Tethys (e.g. Rögl and Steininger, 1983; Rögl, 1999; Popov et al., 2004). However, the presence of numer- ous endemic species among the Oligo-Miocene fauna and flora of the Paratethys and NAFB renders stratigraphic correlation with the Tethys realm difficult (see Piller et al., 2007). As a result, regional chrono- stratigraphic stages have been introduced for the Oligocene and Mio- cene Series in the Central Paratethys realm, and are also widely used for the Molasse sediments of the NAFB (Fig. 2). The NAFB extends from the Rhône Basin in the west via Switzerland and southern Germany to Lower Austria in the east (Fig. 1A). The Swiss and SW German sectors of the NAFB correspond to the area of the West- ern Paratethys, while the SE German and Austrian portions represent the western zone of the Central Paratethys. The sedimentary fill of the NAFB Basin, which reaches thicknesses of over 5000 m in places, includes largely siliciclastic marine, brackish and terrestrial sediments and represents one of the most continuous Oligocene-Miocene archives in Europe (e.g. Schlunegger et al., 1997; Kuhlemann and Kempf, 2002; Abdul Aziz et al., 2010). In the Swiss and SW German segment of the NAFB, the sedimenta- ry succession as a whole is divided into two transgressive-regressive megacycles, which are separated by an extensive unconformity (e.g. Lemcke, 1988; Bachmann and Müller, 1992). The first megacycle (Oligo- cene to lowermost Miocene) comprises the lithostratigraphic groups of the Lower Marine Molasse, Lower Brackish Molasse and Lower Freshwa- ter Molasse, while the second megacycle (lower Miocene to upper Mio- cene) consists of the Upper Marine Molasse, Upper Brackish Molasse and Upper Freshwater Molasse (e.g. Doppler et al., 2005). An especially interesting time span in the geological history of the NAFB is the late Early Miocene (middle to late Burdigalian, Central Paratethys stages Ottnangian and Karpatian) because this interval saw significant changes in palaeoenvironmental conditions in the region (e.g. Lemcke, 1988; Kuhlemann and Kempf, 2002). Lower Ottnangian sediments are usually fully marine, middle Ottnangian successions are dominated by restricted marine conditions, upper Ottnangian sediments Palaeogeography, Palaeoclimatology, Palaeoecology xxx (2017) xxx–xxx ⁎ Corresponding author. E-mail addresses: m.pipperr@lrz.uni-muenchen.de (M. Pippèrr), b.reichenbacher@lrz.uni-muenchen.de (B. Reichenbacher). PALAEO-08134; No of Pages 18 http://dx.doi.org/10.1016/j.palaeo.2017.01.002 0031-0182/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Please cite this article as: Pippèrr, M., Reichenbacher, B., Late Early Miocene palaeoenvironmental changes in the North Alpine Foreland Basin, Palaeogeogr. Palaeoclimatol. Palaeoecol. (2017), http://dx.doi.org/10.1016/j.palaeo.2017.01.002