Stratal, sedimentary and faunal relationships in the Coniacian 3rd-order sequence of the Iberian Basin, Spain

The Tethyan oyster Pycnodonte (Costeina) costei (Coquand, 1869) in the Coniacian (Upper Cretaceous) of the Iberian Basin (Spain): Taxonomic, palaeoecological and palaeobiogeographical implications

“…Early diagenetic processes did not significantly affect the carbonate facies and therefore, the fossil content is abundant and well preserved in these carbonate facies (Gil-Gil et al, 2002García-Hidalgo et al, 2012;Font et al, 2013) (Fig. 3).…”

“…Here, this species can be found as dense concentrations of large, mostly articulated specimens. Ammonites (Tissotioides hispanicus, Prionocycloceras iberiense, Tissotia sp., Hemitissotia ceadouroensis, H. turzoi: García-Hidalgo et al, 2012;Barroso-Barcenilla et al, 2013;Segura et al, 2014) are common in this stratigraphic succession of the Hortezuelos Formation, allowing a detailed biostratigraphic framework correlative to the middle Coniacian Gauthiericeras margae and the upper Coniacian Paratexanites serratomarginatus zones.…”

“…1). Despite the predominance of shallow water and coastal facies, there are two depositional sequences showing deep and open platform facies in most of the basin and close to the coastal margin (Barroso-Barcenilla et al, 2011;García-Hidalgo et al, 2012;Segura et al, 2014). They correlate to the globally recognised eustatic maxima at the Cenomanian/Turonian boundary and in the Coniacian (Hardenbol et al, 1998;Haq, 2014).…”

“…In more recent years this species was also widely recorded in the Iberian Basin (Spain), as a result of field-work studies concerning a highresolution analysis of depositional architecture for the Upper Cretaceous successions (Gil-Gil et al, 2009;García-Hidalgo et al, 2012). These samples include large specimens that closely resemble those documented from North Africa, which occur in association with many other Tethyan molluscs.…”

“…The central and northern parts of the basin (Fig. 1) are mainly composed of nodular marls, clayey limestones, and detrital and bioclastic limestones of the Hortezuelos Formation, displaying a vertical stacking where three distinctive members are recognised (García-Hidalgo et al, 2012): i) a lower member, composed of thickening-upwards bioclastic/oolitic thinbedded limestones; ii) a highly fossiliferous middle member, composed of grey marls and nodular clayey limestones, grading upwards to bioclastic limestones; and iii) an upper member, composed of mediumto thick-bedded limestones ranging from micrite-(mudstone) to bioclastic-rich floatstones, rudstones, and grainstones and, occasional rudistid biostromes (Gil-Gil et al, 2002 (Fig. 2).…”