Understanding coleoid migration patterns between eastern and western Europe – belemnite faunas from the upper lower Maastrichtian of Hrebenne, southeast Poland

From pristine aragonite to blocky calcite: Exceptional preservation and diagenesis of cephalopod nacre in porous Cretaceous limestones

“…The aragonite-bearing sections are located in the Roztocze area, which is a range of hills extending from the area of the town of Kraśnik (southeast Poland) to the town of Lviv (western Ukraine) with the Campanian and Maastrichtian deposits outcropping in several places (see [24] for the stratigraphy of key sections in Poland and [29] for the same for the Ukrainian part of Roztocze). No specific permissions were required to access these locations, which are not part of a protected area.…”

“…The quarry section exposes approximately 15 meters of siliceous limestones that alternate with thin marly intercalations; the section yielded abundant marine macrofossils including ammonites, nautilids (aragonite relics were only found in fossils of these two groups), belemnites and bivalves as well as well-preserved remains of leaf flora transported from the nearby land area [31]. Stratigraphically, the Krasnobród section spans the Campanian/Maastrichtian boundary, representing the uppermost Campanian Belemnella inflata Zone in its lower part and the lowermost Maastrichtian Belemnella vistulensis Zone [24] in the upper one. In terms of the inoceramid zonation of Walaszczyk et al [32,33], the lowermost portion of the quarry section belongs to the “Inoceramus” costaecus Zone, its major component representing the “ Inoceramus ” redbirdensis Zone, the upper part of which comprises the Campanian/Maastrichtian boundary [24,32,33].…”

“…Stratigraphically, the Krasnobród section spans the Campanian/Maastrichtian boundary, representing the uppermost Campanian Belemnella inflata Zone in its lower part and the lowermost Maastrichtian Belemnella vistulensis Zone [24] in the upper one. In terms of the inoceramid zonation of Walaszczyk et al [32,33], the lowermost portion of the quarry section belongs to the “Inoceramus” costaecus Zone, its major component representing the “ Inoceramus ” redbirdensis Zone, the upper part of which comprises the Campanian/Maastrichtian boundary [24,32,33]. No data on the precise location of our specimens in the section are available, so they may be of latest Campanian or earliest Maastrichtian in age.…”

“…To date, no fossils with preserved original aragonitic shells have been reported from these deposits; the formerly aragonitic shells typically occur as moulds (Fig 1A–1C; see also [21–23]) or entirely transformed (calcitized) specimens. This is in stark contrast to primarily calcitic skeletons or their parts (e.g., belemnite rostra), which are typically morphologically well preserved (e.g., [24]). Unexpectedly, in some Upper Cretaceous siliceous limestone sections in Poland and Ukraine (S1 Fig), we found nautilid and ammonite moulds with iridescence on their surfaces (Fig 1D and 1E) characteristic of original lustrous, aragonitic layers of mother-of pearl [25,26].…”

A bioclast-based astronomical timescale for the Maastrichtian in the type area (southeast Netherlands, northeast Belgium) and stratigraphic implications: the legacy of P.J. Felder

“…According to Dubicka & Peryt (2016), B. sidestrandensis occurs in the middle upper Campanian up to the lower Trochoceramus radiosus inoceramid zone (lower Maastrichtian). Remin (2018) proposed to correlate this inoceramid zone roughly with the Belemnella sumensis Zone, implying that the presence and LAD of B. sidestrandensis in interval 0 of the Vijlen Member indicate the lower, latest the middle Belemnella sumensis Zone.…”