Data for: Oxfordian carbon-isotope stratigraphy and pelagic biofacies of the Middle–Upper Jurassic transition in the Tethys–Central Atlantic connection

A bulk carbon-isotope stratigraphy, based on high-resolution sampling of five stratigraphic ammonite-dated sectionsfrom pelagic swells of the Subbetic basin (External Zones of the Betic Cordillera, southern Spain) is presented. Thestudied sections are characterized by Callovian‒Oxfordian stratigraphic successions located in the South Iberianpalaeomargin, a key area connecting the Central Atlantic to the Tethys oceans. The rocks are mainly nodularlimestones with common extreme condensation (rosso ammonitico facies). Discontinuities with hiatuses of variableduration, submarine “hardgrounds”, Fe-Mn ooids, limonite crusts, and neptunian dykes are observed around theCallovian/Oxfordian boundary. The stratigraphic record, although very time-averaged, allows for a consistent andaccurate ammonite chronostratigraphy. The carbon isotopes of marine carbonates show a marked trend towards highδ13C values from Lower Oxfordian to the Middle Oxfordian (~4.3 ‰, near the Plicatilis/Transversarium boundary). Theisotopic values stand between 2.7–3.0 ‰ at the Upper Oxfordian (Bifurcatus and Hypselum Zones) and lowermostKimmeridgian (Bimammatum Zone); afterward δ13C values decrease and reach a relative minimum (~2.3–2.5 ‰) inthe Lower Kimmeridgian (Bimammatum/Planula boundary). Finally, isotopic values increase again (~2.6–2.7 ‰) in thelower Kimmeridgian (mid part of the Planula Zone). Comparison of carbon-isotope stratigraphy between Subbetic andother Tethyan areas shows similar trends. The replacement of thin-shelled bivalves by planktonic foraminifers andradiolarians that took place in the Callovian/Oxfordian boundary can be associated to the widening of the trans-Pangaean seaway . This, in turn, triggered the global warming which increased nutrients concentration in upper watercolumn due to intensified nutrient input by river plumes. These phenomena are concomitant with the major Oxfordianδ13C positive excursion and with a transgressive cycle.