Sea-water circulation on an oolite-dominated carbonate system in an epeiric sea (Middle Jurassic, Switzerland) ANDREAS WETZEL*, HELMUT WEISSERT † , MONIKA SCHAUB* ,1 and ANDREA R. VOEGELIN* ,2 *Geologisch-Pal € aontologisches Institut, Universit€ at Basel, Bernoullistrasse 32, CH-4056, Basel, Switzerland (E-mail: andreas.wetzel@unibas.ch) †Geologisches Institut, ETH-Zentrum, CH-8092, Z€ urich, Switzerland Associate Editor – Karl F€ ollmi ABSTRACT The Middle Jurassic Burgundy carbonate platform occupied a central part of the Central European Epeiric Sea during the Middle Jurassic. The facies architecture of the oolitic calcarenite bodies was affected by tidal currents on the platform and relative sea-level changes. The d 13 C-values of inorganic carbonates, sampled in biostratigraphic-defined intervals, do not match very well between closely spaced sections and, hence, are of restricted use for stratigraphic purposes. It appears that the platform interior might have been decoupled from the global carbon pool. Although deposited in a rapidly accumulating setting, the recorded isotope signatures might be affected by some local stratigraphic gaps. Nonetheless, the carbon isotope data imply lat- eral changes of the platform waters; these appear to be related to the position on the platform and to the sediment dispersal pattern, as evidenced by clay minerals. Adjacent to the eastern margin of the platform, detrital chlorite and illite occur in considerable proportions, both ascribed to a boreal source to the east and the north-east. In contrast, smectite-rich mixed-layer clay min- eral content increases significantly towards the platform interior, pointing to a delivery from the north-west. All these data are suggestive of an overall clockwise current pattern in the Central European Epeiric Sea during the Middle Jurassic. Keywords Carbon isotope stratigraphy, central Europe, circulation, clay mineralogy, epeiric sea, Middle Jurassic. INTRODUCTION For most of Earth history, wide areas on the conti- nents have been covered by extensive epeiric seas, which were far larger than today. Such times, for instance the Middle and Late Mesozoic, therefore represent a non-actualistic scenario, because there are no equivalent modern coun- terparts (Scotese, 2002). Long-term subsiding epicontinental basins can house large quantities of valuable resources including hydrocarbons, pure limestone, clays, salts or, when defined intervals act as aquifers, water. Therefore, these ancient non-actualistic depositional systems require a detailed investigation to understand bet- ter and predict facies in space and time (Pratt & Holmden, 2008 and papers therein). Among the effects of sea-level change, sedi- ment accumulation and subsidence, that are all addressed by sequence stratigraphic methods, 1 Present address: B€ ohringer AG, M€ uhlegasse 10, CH-4104 Oberwil, Switzerland 2 Present address: Institute of Geography and Geology, Denmark and Nordic Center for Earth Evolution (NordCEE), University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen, Denmark © 2012 The Authors. Journal compilation © 2012 International Association of Sedimentologists 19 Sedimentology (2013) 60, 19–35 doi: 10.1111/sed.12007