Astronomical insolation forcing is well established as the underlying metronome of Quaternary ice ages and Cenozoic climate changes. However, its effects on earlier eras (Mesozoic, Paleozoic, and pre-Cambrian) are less understood. In the first part of this presentation, I will argue that formally defining 405,000-year eccentricity cycles as chronostratigraphic units (astrochronozones) throughout the Phanerozoic eon is a crucial research goal for the next decade. Establishing a common cyclostratigraphic framework to harmonize cyclostratigraphies between key sections in Europe and North America (in particular for the Devonian) is of primary importance. The goal of defining Phanerozoic astrochronozones would enhance our understanding of how astronomical forcing has shaped Earth's climate over geologic time.

Subsequently, I will discuss several lines of evidence suggesting that Devonian oxygen deficiency was sensitive to rhythmic astronomical forcing. Nonetheless, the question of why some anoxic events were more severe than others remains unresolved. Therefore, it is increasingly important to employ cyclostratigraphy to distinguish between different climate modes of the Devonian and to improve our understanding of the role of astronomical forcing in Devonian ocean anoxic events.

Rhenish Massif and Ardennes are the type regions of the classic Gedinnian, Siegenian, and Emsian stages (and subunits) of the Lower Devonian, which are mainly defined by brachiopods. In the course of the ongoing taxonomic revision of the Rhenish Lower Devonian representatives of the phylum, numerous new biostratigraphic data have been obtained. The revised biostratigraphy includes 25 taxon range and 20 assemblage zones from the Pridoli to the Eifelian, which can be further subdivided into subzones. Although Lochkovian, Pragian, and Emsian GSSPs have long been defined elsewhere on the basis of pelagic guide fossils, the classic Ardenno-Rhenish stratigraphy is still an important reference in the Lower Devonian, e.g., for the envisaged redefinition of the basal Emsian GSSP.

The biostratigraphic utility of brachiopods is restricted both by their limited palaeogeographic distribution and their dependence on the facies. In the case of the Rhenish Lower Devonian, specific subtypes of the rhenotypic facies have to be considered (e.g., eurhenotypic, allorhenotypic and pararhenotypic facies). Nevertheless, the Rhenish brachiopods are excellent guide fossils, and thanks to close palaeobiogeographic relationships the revised biostratigraphy can be used with reservations in Western Europe and North Africa, i.e., within the boundaries of a ‘Maghrebo-European’ palaeobiogeographic unit. Here, correlations of regional brachiopod and global pelagic biostratigraphies are possible. To conclude, it can be said that the revised Lower Devonian brachiopod stratigraphy has the potential of providing a fine-scaled biochronological framework for future stratigraphic, palaeoecological, and palaeobiogeographic studies.

The super-continent Pangea was characterised by strong continentality because of climatic change from an icehouse earth during late Pennsylvanian and early Permian via an increasingly warm earth during middle–late Permian into the early Triassic super-hot house. Consequently, marine incursions, caused by the glacial cycles (cyclothems), decreased during the early Permian. Because of increasingly absent marine deposits in the Permian, the correlation of the continental deposits with marine zone-fossils (ammonoids, conodonts, fusulinids) becomes complicated. Very helpful for the correlation would be radioisotopic ages from intercalated volcanites. Unfortunately, during late early Permian, volcanism decreased in the continental Euramerica. In the middle and late Permian, no radioisotopic ages exist so far for Euramerica. Newest Late Pennsylvanian and earliest Permian radioisotopic ages based on the U-Pb CA-ID-TIMS (chemical abrasion-isotope dilution-thermal ionisation mass spectrometry) method fit well with continental and marine biostratigraphic correlations. However, some new high-precision U-Pb CA-ID-TIMS ages, especially from the Thuringian Forest Basin, conflict with the biostratigraphy and other radioisotopic ages in European basins. They are even in contrast to the climate-stratigraphy in Euramerica, particularly to the outspread of wet and, later, dry reds beds, which, of course, only provide rough interregional time markers. The question arises, what do these highly precise radioisotopic ages tell us? Are they really the decisive eruption ages or do they represent (far) older crystallisation processes in the magma chamber? In any case, we should only trust ages (and even biostratigraphic data) that are supported by cross-correlations with data from different independent stratigraphic methods.

The world’s largest ammonite, Parapuzosia (P.) seppenradensis (Landois, 1895), has fascinated the world since the discovery in 1895 of a specimen measuring 1.74 metres (m) in diameter near Seppenrade in Westfalia, Germany. Subsequent findings of this taxon have been rare. For this study (Ifrim et al., 2021), the historical specimens have been revised, and abudant material from England and Mexico was documented. It comprises 154 specimens of large (< 1 m diameter) to giant (> 1m diameter) Parapuzosia from the Santonian and lower Campanian, mostly with stratigraphical information. High-resolution integrated stratigraphy allows for precise trans-Atlantic correlation of these occurrences. The Tepeyac section in northeastern Mexico, where 66 specimens of diameters from 10 to 150 cm were found in their original layer was documented with integrated stratigraphy. With 330 ammonoids and >100 inoceramids, among other fossils, it is the section with the richest fossil record in that interval. It has become Associated Stratotype Section and Point for the base of the Campanian (Gale et al. 2023). The high- resolution correlation allows for further insight into the palaeobiology, evolution and dispersal of worlds largest ammonite

References
Gale, A., et al. 2023. The Global Boundary Stratotype Section and Point (GSSP) of the Campanian Stage at Bottaccione (Gubbio, Italy) and its Auxiliary Sections: Seaford Head (UK), Bocieniec (Poland), Postalm (Austria), Smoky Hill, Kansas (U.S.A), Tepayac (Mexico). Episodes. doi: 10.18814/epiiugs/2022/022048.
Ifrim, C. et al. 2021. Ontogeny, Evolution and palaeobiogeographic distribution of Parapuzosia (P.) seppenradensis, the world's largest ammonite. PLoS ONE 16, e0258510. doi: 10.1371/journal.pone.0258510.

After the peak warmth’s of mid-Cretaceous times, progressive climate cooling occurred during the late Cretaceous, with a global temperature decline in the order of Cenozoic cooling without signs of major and persistent glaciation. Thereby, the Maastrichtian marks a cool greenhouse period with different non-analog boundary conditions in comparison to today. Global mean temperatures, polar ice extents, regions of deep-water formation, types of vegetation, as well as patterns and variability of precipitation and evaporation were all different. Repeated multi-million-year long periods of climate cooling and warming occurred during the cool Maastrichtian greenhouse. Particularly, the latest Campanian–early Maastrichtian witnessed substantial deep-water cooling as well as a carbon cycle perturbation expressed by a long-lasting negative carbon isotope excursion. Our understanding of climate and carbon cycle dynamics is still limited for times prior 66 million years, particularly for the Campanian–Maastrichtian transition. The lack of highly resolved stratigraphy introduces severe uncertainties in the quality and interpretation of global correlation. Here we present the present state in the development of an astrochronology for the Maastrichtian stage that integrates sedimentary cyclicity, carbon isotope and magnetostratigraphy in combination with biostratigraphic events from the successions of Zumaia, Sopela, Bidart and the GSSP locality Tercis-les-Bains belonging to the Basque-Cantabrian and Aquitain basins in Spain and France. The development of a Bay of Biscay Maastrichtian record will provide new insights about the phase relation between orbital forcing and carbon cycle response, as well as temporal relations to changes in ocean chemistry, circulation and sea level, and the ecosystem response.