One basin, threefold lithostratigraphy. Discussion of stratigraphic correlation of the Saxon-Bohemian Cretaceous Basin (Upper Cretaceous; Germany and Czechia)

Stratigraphic subdivision of the Upper Cretaceous in Saxony and northern Bohemia has been significantly improved during the recent years, particularly on the Saxon side, and proposals for transboundary correlation were made. In the past few years, the hydrogeological exploration on the Czech side brought important new data (including several cored and well-logged boreholes; see Appendix) that facilitated more precise correlation of aquifer formations for groundwater modelling. Here, we present a revised stratigraphic correlation of sandstone-dominated areas of the Saxon-Bohemian Cretaceous Basin between Pirna and the Zittau Mts., supported by the new data and corroborated by thorough discussion of previously published stratigraphic correlation schemes. Correlation of the Cenomanian-Lower Turonian is relatively reliable with respect to the other most recent attempts, and only minor issues are discussed. The Upper Cenomanian Pennrich Fm. represents a locally developed, glauconite-rich lithofacies - as indicated by development of the Korycany Mb. The lower part of the Oybin Fm. (lower Turonian) has a markedly lower thickness, as indicated by its correlation to the B & iacute;l & aacute; Hora Fm. Thus, its actual top is either placed ca. 40 m higher or it contains two coarsening-upward cycles. The middle-upper Turonian Jizera Fm. largely correlates to the Postelwitz Fm. and middle-upper part of the Oybin Fm., respectively. The exact correlation of overlying sandstones c-d (upper Turonian) of the Postelwitz and Schrammstein formations, to individual coarsening-upward cycles within the Jizera Fm., is problematic for scarcity of fossil markers, rapid facies transitions and relatively limited database (number of boreholes and outcrops of certain units). Therefore, we present an alternative correlation of the Schrammstein Fm. based on the available borehole and outcrop data from both sides of the border, and consider plausibility of stratigraphic equivalence of sandstones d to f and the Teplice Fm. Sandstones d and e, compared to sandstones a to c, were likely deposited within significantly less extensive depositional space that gradually diminished from SW to NE, with the youngest Turonian Kyjov Sandstone (overlain by transgressive Ch & rcaron;ibsk & aacute; Mudstone) being the least extensive. Lithostratigraphic correlation of the youngest Upper Cretaceous units in the Zittau and Lusatian Mts. revealed the following: (i) The upper Turonian L & uuml;ckendorf Fm. combines lithologically contrasting successions with poorly defined boundaries and unknown thickness. It was described on discontinuous sections and does not reasonably correlate with the Czech stratigraphy; (& uuml;) the overlying Waltersdorf Fm. lacks a proper definition (e.g. type section is missing), although it has been subdivided into three sandstone members thought to represent a stratigraphic succession; (iii) the Sonnenberg Sandstone that correlates to the Kyjov Sandstone, has clearly defined boundaries and distinct lithology and can be cartographically displayed. Both units can be combined and formally defined as a member within the Waltersdorf and Teplice formations, respectively; (iv) the Lausche and Hochwald sandstones as members of the Waltersdorf Fm. have no counterparts in the Czech territory due to a limited accessibility and impossibility of their recognition within a variable lithofacies succession of the B & rcaron;ezno Fm. However, both units may be treated as informal stratigraphic units of local significance.