naa a22 4500 510808638 CHVBK 20180411083430.0 cr unu---uuuuu 180411e20130301xx s 000 0 eng 10.1007/s12542-012-0149-x doi (NATIONALLICENCE)springer-10.1007/s12542-012-0149-x Taphonomic differentiation of Oxfordian ammonites from the Cracow Upland, Poland [Elektronische Daten] [Agata Jurkowska, Bogusław Kołodziej] Taphonomic analysis of Lower and Middle Oxfordian ammonites from the Cracow Upland, southern Poland (localities at Podłęże, Zalas, Młynka) revealed differences in ammonite preservation. The studied ammonites, usually termed as external and internal moulds, show a more complex state of preservation. In the Middle Oxfordian glauconitic marls, ammonites are preserved as internal moulds with neomorphic calcite shells showing relics of the original internal structure. In the Middle Oxfordian platy peloidal limestones, ammonites are preserved mostly as external moulds, without septal suture, however under microscope might show relics of internal whorls and septa and/or subtle differences in sediment filling phragmocone chambers. In sponge-microbial bioherms and biostromes, ammonite internal moulds have shells, which in contrast to ammonites from glauconitic marls are not strictly neomorphic ones, but originated by shell dissolution and subsequent filling of moldic porosity by calcite cement. In sponge-microbial nodular limestones, the ammonites are strongly deformed and the outer wall is usually removed by dissolution under pressure. Other important taphonomic differences include the rate of compaction (highest in platy limestones), sedimentary infillings, microborings, encrustations and preservation of siphuncular tubes. The majority of the ammonites appear to be phragmocones; aptychi in all facies are rare. Siphuncular tubes are fossilized exclusively in oppeliids, only in specimens from glauconitic marls and platy limestones, although their other taphonomic attributes are different. Tubes seem to have fossilized due to microbially mediated phosphatization that could be favoured by a set of parameters which operated rather at the scale of ammonoid carcasses: closed, poorly oxygenated conditions, and reduced pH. Taphonomic processes were controlled by the sedimentary environment (fragmentation, sedimentary filling, phosphatization of siphuncular tubes), as well as by early and late diagenesis (neomorphic transformation, dissolution, cementation, compaction) influenced by lithology. The Author(s), 2012 Ammonites nationallicence Taphonomy nationallicence Phosphatization nationallicence Oxfordian nationallicence Polish Jura Chain nationallicence Cracow Upland nationallicence Ammoniten nationallicence Taphonomie nationallicence Phosphatisierung nationallicence Oxfordium nationallicence Krakauer Hochland nationallicence Südpolen nationallicence Jurkowska Agata Institute of Geological Sciences, Jagiellonian University, ul. Oleandry 2a, 30-063, Kraków, Poland aut Kołodziej Bogusław Institute of Geological Sciences, Jagiellonian University, ul. Oleandry 2a, 30-063, Kraków, Poland aut Paläontologische Zeitschrift Springer-Verlag 87/1(2013-03-01), 67-82 0031-0220 87:1<67 2013 87 12542 https://doi.org/10.1007/s12542-012-0149-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s12542-012-0149-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jurkowska Agata Institute of Geological Sciences, Jagiellonian University, ul. Oleandry 2a, 30-063, Kraków, Poland aut NATIONALLICENCE 700 1- Kołodziej Bogusław Institute of Geological Sciences, Jagiellonian University, ul. Oleandry 2a, 30-063, Kraków, Poland aut NATIONALLICENCE 773 0- Paläontologische Zeitschrift Springer-Verlag 87/1(2013-03-01), 67-82 0031-0220 87:1<67 2013 87 12542 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer