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Following the unanimous vote of the Executive Committee of International Union of Geological Sciences in October 2022, the Global boundary Stratotype Section and Point for the base of the Campanian Stage is confirmed as the magnetic polarity reversal from Chron 34n (top of the Long Cretaceous Normal Polarity–Chron) to Chron C33r at the 221.53 m level in the Bottaccione Gorge section at Gubbio, Umbria–Marche Basin, Italy. This event has been widely identified in oceanic settings and in widespread onshore outcrops. Sedimentation across the Santonian–Campanian boundary interval in the proposed GSSP appears to be continuous, supported by evidence from the carbon isotope record and complete micro– and nannofossil biostratigraphy. The succession comprises deep–water cherty limestones (mudstones and foraminiferal wackestones) which provide a detailed record of calcareous nannofossils and planktonic foraminifera and yields an excellent palaeomagnetic record. The high–resolution carbon isotope record, derived from bulk sediment, provides an important additional means of correlation to other regions.

The organic matter content of marine sediments is often used to infer past changes in ocean conditions. However, the organic carbon pool preserved in coastal sediments is a complex mixture derived from different sources and may not reflect in situ processes. In this study, we combine taxonomic identification of reworked palynomorphs with pyrolysis organic geochemistry and reflected-light organic petrographic microscopy to investigate the provenance, composition and preservation of organic matter in a marine sediment core retrieved from the NE Greenland shelf. Our study reveals continuous yet variable input of land-derived organic carbon to the marine environment throughout the late Younger Dryas–Holocene, with the highest input of inert carbon in the late Younger Dryas. Although the sediments contain some recent marine palynomorphs, there is no other evidence of fresh marine organic carbon. In contrast, our results indicate that these shelf sediments represent a significant sink of recycled organic carbon. The results of pyrolysis geochemistry revealed that ~90% of the total organic carbon in the sediments is inert. The organic petrography analyses revealed that >70–84% of the organic carbon in the sediment core is terrigenous. Reworked dinoflagellate cysts showed a continuous provenance of Cretaceous land-derived material, most likely from the nearby Clavering Island. Our study points to the importance of constraining the organic matter origin, composition and preservation in marine sediments to achieve more accurate palaeoenvironmental reconstructions based on organic proxies.

We integrate previous Bayesian and astronomically tuned age calibrations of the calcareous nannofossils events with our large-scale correlations to discuss using the standard calcareous nannofossil zonal schemes in the SW Neo-Tethys platform during a period of significant paleoceanographic, tectonic, and paleoclimatic perturbations (middle Eocene to early Oligocene). Two marine on-land sections extend from NP15 (Nanno-Plankton zone) to lower NP23, equivalent to upper CNE9 (Calcareous Nannofossil of the Eocene) to lower CNO3 (Calcareous Nannofossil of the Oligocene), are studied. Calcareous nannofossils have been investigated at less than 96 kyr resolution between 45.55 Ma and 31.9 Ma. The Souar section covers the Top (T) of the Nannotetrina alata group zone (CNE9, Lutetian) to the Isthmolithus recurvus zone (CNE18, Priabonian) in the Pelagic facies of the Tunisian dorsal. The El Rahma section extends from the Helicosphaera compacta zone (CNE21) to the Reticulofenestra umbilicus (CNO2) zone in the Cap Bon peninsula. The distribution patterns were studied through semi-quantitative counts to test the reliability of the biohorizons used in the standard biozonations schemes (Martini, 1971; Agnini et al., 2014). We discuss 14 biohorizons that span 13.65 Myr to highlight the limitations (absence/scarcity) of the Chiasmolithus group, particularly Ch. grandis, Ch. oamaruensis, and Ch. solitus, as biohorizons in the SW Neo-Tethys. Our study shows that Sphenolithus furcatolithoides, Dictyococcites bisectus, Sphenolithus obtusus, and Reticulofenestra erbae are reliable horizons for large-scale correlations with the northern margins of the Neo-Tethys. Calcareous nannofossils from the SW Neo-Tethys margin were highly affected by the paleo-circulation changes due to the episodic restriction of the westward subtropical Eocene Neo-Tethys (STENT) current (Jovane et al., 2009), followed by the closure of the eastern Neo-Tethys.

y Ikaite and pseudomorphs thereafter (“glendonites”) are a potentially powerful tool for palaeoclimatic studies, as a low-temperature proxy. However, much uncertainty still surrounds the drivers of ikaite formation, in particular prerequisite thermal and chemical conditions. Furthermore, the ikaite to glendonite transformation is not fully understood, and it was unclear which calcite phases in glendonites were ikaite-derived and which were later diagenetic calcites. This leads to difficulties in choosing which phase to analyse in order to reconstruct the original ikaite growth environmental conditions. Petrographic examination of air-transformed ikaite from the Isatkoak Lagoon in Utqiaġvik, Alaska, confirms that both ’Type I’ and ’Type II’ calcite phases seen in glendonites are directly derived from ikaite breakdown and not from secondary sources. Clumped isotope temperature reconstructions for transformed ikaites from Utqiaġvik, and comparison to Recent glendonites from the White Sea, Russia, confirm that clumped isotope thermometry may be used to reconstruct ikaite growth temperatures, whilst stable isotopes and minor elemental analysis reveal that a range of geochemical conditions characterise ikaite growth sites.

A peculiar record of previously undescribed and/or rarely described nannoliths from the Hettangian to lower Pliensbachian of the Llanbdr (Mochras Farm) core, Wales (UK) is documented here. Some of the observed morphotypes are assigned to didemnid ascidians, commonly observed in the upper Rhaetian, as evidence of the resilience of ascidian tunicates during the end-Triassic mass extinction. One newly described nannolith present throughout the Hettangian and Sinemurian, Quadrifolium hesselboi, is similar to forms previously observed in the upper Rhaetian, and is therefore considered to be a new nannofossil survivor from the end-Triassic mass extinction. High-amplitude changes observed in the absolute and relative abundances of nannoliths, schizosphaerellids and coccoliths across the Hettangian suggest a recovery interval from the end-Triassic crisis spanning the planorbis–liasicus ammonite zones in four distinct steps with high volatility in environmental conditions, followed by the establishment of more stable environmental conditions in the angulata ammonite zone.

Drilling for the International Continental Scientific Drilling Program (ICDP) Early Jurassic Earth System and Timescale project (JET) was undertaken between October 2020 and January 2021. The drill site is situated in a small-scale synformal basin of the latest Triassic to Early Jurassic age that formed above the major Permian-Triassic half-graben system of the Cheshire Basin. The borehole is located to recover an expanded and complete succession to complement the legacy core from the Llanbedr (Mochras Farm) borehole drilled through 1967-1969 on the edge of the Cardigan Bay Basin, North Wales. The overall aim of the project is to construct an astronomically calibrated integrated timescale for the Early Jurassic and to provide insights into the operation of the Early Jurassic Earth system. Core of Quaternary age cover and Early Jurassic mudstone was obtained from two shallow partially cored geotechnical holes (Prees 2A to 32.2g¯m below surface (mg¯b.s.) and Prees 2B to 37.0g¯mg¯b.s.) together with Early Jurassic and Late Triassic mudstone from the principal hole, Prees 2C, which was cored from 32.92 to 651.32g¯m (corrected core depth scale). Core recovery was 99.7g¯% for Prees 2C. The ages of the recovered stratigraphy range from the Late Triassic (probably Rhaetian) to the Early Jurassic, Early Pliensbachian (Ibex Ammonoid Chronozone). All ammonoid chronozones have been identified for the drilled Early Jurassic strata. The full lithological succession comprises the Branscombe Mudstone and Blue Anchor formations of the Mercia Mudstone Group, the Westbury and Lilstock formations of the Penarth Group, and the Redcar Mudstone Formation of the Lias Group. A distinct interval of siltstone is recognized within the Late Sinemurian of the Redcar Mudstone Formation, and the name "Prees Siltstone Member"is proposed. Depositional environments range from playa lake in the Late Triassic to distal offshore marine in the Early Jurassic. Initial datasets compiled from the core in

The Mochras core, UK, an historic reference site for the study of Early Jurassic cal-careous nannofossils, has been reinvestigated here across the Hettangian to Lower Pliensbachian. Both relative and absolute abundances of 24 calcareous nannofossil species reveal patterns and occurrences that define not less than 37 defined biohorizons. However, due to the low abundance of many of those species towards the base and top of their stratigraphical range, we observe large inconsistencies in first and last occurrences of these species. Instead, we consider records of first consistent and last consistent occurrences (FCOs and LCOs), as well as base and top of acme events, as more reliable biohorizons. Accordingly, we assess the reliability of our biohorizons and show that, in addition to previously established zonal and sub-zonal biomarkers, nine non-zonal biohorizons prove to be robust. Based on that, an updated biozonations scheme with additional subzones for NJB has been proposed and tested against other localities.

Drilling for the International Continental Scientific Drilling Program (ICDP) Early Jurassic Earth System and Timescale project (JET) was undertaken between October 2020 and January 2021. The drill site is situated in a small-scale synformal basin of the latest Triassic to Early Jurassic age that formed above the major Permian–Triassic half-graben system of the Cheshire Basin. The borehole is located to recover an expanded and complete succession to complement the legacy core from the Llanbedr (Mochras Farm) borehole drilled through 1967–1969 on the edge of the Cardigan Bay Basin, North Wales. The overall aim of the project is to construct an astronomically calibrated integrated timescale for the Early Jurassic and to provide insights into the operation of the Early Jurassic Earth system. Core of Quaternary age cover and Early Jurassic mudstone was obtained from two shallow partially cored geotechnical holes (Prees 2A to 32.2 m below surface (m b.s.) and Prees 2B to 37.0 m b.s.) together with Early Jurassic and Late Triassic mudstone from the principal hole, Prees 2C, which was cored from 32.92 to 651.32 m (corrected core depth scale). Core recovery was 99.7 % for Prees 2C. The ages of the recovered stratigraphy range from the Late Triassic (probably Rhaetian) to the Early Jurassic, Early Pliensbachian (Ibex Ammonoid Chronozone). All ammonoid chronozones have been identified for the drilled Early Jurassic strata. The full lithological succession comprises the Branscombe Mudstone and Blue Anchor formations of the Mercia Mudstone Group, the Westbury and Lilstock formations of the Penarth Group, and the Redcar Mudstone Formation of the Lias Group. A distinct interval of siltstone is recognized within the Late Sinemurian of the Redcar Mudstone Formation, and the name “Prees Siltstone Member” is proposed. Depositional environments range from playa lake in the Late Triassic to distal offshore marine in the Early Jurassic. Initial datasets compiled from the core include ra