The early to middle Eocene is marked by prominent changes in calcareous nannofossil assemblages coinciding both with long-term climate changes and modification of the North Atlantic deep ocean circulation. In order to assess the impact of Eocene climate change on surface water environmental conditions of the Northwest Atlantic, we developed calcareous nannoplankton assemblage data and bulk stable isotope records (δ 18 O and δ 13 C) across an early to middle Eocene interval (~52-43 Ma) at Integrated Ocean Drilling Program Site U1410 (Southeast Newfoundland Ridge,~41°N). At this site, early Eocene sediments are pelagic nannofossil chalk, whereas middle Eocene deposits occur as clay-rich drift sediments reflecting the progressive influence of northern-sourced deep currents. Between the end of Early Eocene Climatic Optimum (EECO) and the Ypresian/Lutetian boundary, calcareous nannofossils switched from an assemblage mainly composed of warm-water and oligotrophic taxa (Zygrhablithus, Discoaster, Sphenolithus, Coccolithus) to one dominated by the more temperate and eutrophic reticulofenestrids. The most prominent period of accelerated assemblage change occurred during a~2-Myr phase of relatively high bulk δ 18 O values possibly related to the post-EECO cooling. Although the dominance of reticulofenestrids persisted unvaried throughout the middle Eocene interval, early Lutetian (~47.4 to 47 Ma) stable isotope records indicate a reversal in the paleoenvironmetal trends suggesting a potential restoration of warmer conditions. Importantly, our data indicate that the~2-Myr interval immediately following the EECO was crucial in establishing the modern calcareous nannofossil assemblage structure and also reveal that the establishment of Reticulofenestra-dominated assemblage occurred prior to the onset of persistent deep current system in the Northwest Atlantic.

Despite the widespread use of herbicide glyphosate in cultivation, its extensive runoff into rivers and to coastal areas, and the persistence of this chemical and its main degradation product (aminomethylphosphonic acid, AMPA) in the environment, there is still little information on the potential negative effects of glyphosate, its commercial formulation Roundup® and AMPA on marine species. This study was conducted with the aim of providing a comparative evaluation of the effects of glyphosate-based and its derived chemicals on the larval development of the sea urchin Paracentrotus lividus, thus providing new data to describe the potential ecotoxicity of these contaminants. In particular, the effects on larval development, growth and metabolism were assessed during 48 h of exposure from the time of egg fertilization. The results confirm that AMPA and its parent compound, glyphosate have similar toxicity, as observed in other marine invertebrates. However, interestingly, the Roundup® formulation seemed to be less toxic than the glyphosate alone.

The Upper Cretaceous to Paleocene succession cropping out at the Bottaccione section (Gubbio, central Italy) represents a classical Tethyan setting that served as a standard for the construction of the geomagnetic polarity time scale. Existing biomagnetostratigraphy suggests that the Paleocene interval of the Bottaccione section is condensed relative to other outcrops in the area. Moreover, the thickness of individual magnetochrons compared to other Umbria-Marche successions, suggests that the Bottaccione Paleocene might contain a nonidentified stratigraphic gap. By contrast, a new high-resolution integrated stratigraphic record presented here, including bio-, magneto-, chemo-, and cyclostratigraphy, provides evidence that the Bottaccione record is complete and comparable to other successions outcropping in the Umbria-Marche area as well as records from the South Atlantic and North Pacific.However, the paleomagnetic signal of this classical section is partially corrupted in the upper part of the section, possibly due to diagenetic alteration of clay minerals. The recognition of orbitally-forced sedimentary cycles, corresponding to long eccentricity (405 kyr) and possibly other higher frequency cycles, together with the availability of a well preserved carbon isotope profile, makes the Bottaccione outcrop a potential reference section for comparison with existing carbon isotope records of Early-Middle Paleocene age and an auxiliary setting for the development of an astrochronological time scale in the Paleocene.

Despite the low number of samples included in the study, the described automatic procedure seemed to decrease FXIII activity overestimation and, especially for low activity range samples (<20%), to improve the agreement between FXIII activity and concentration. Our data suggested that iodoacetamide correction could allow the detection of severe FXIII deficiencies (activity <5%) otherwise undiagnosed using the original method.

Cyclostratigraphy and astrochronology are now at the forefront of geologic timekeeping. While this technique heavily relies on the accuracy of astronomical calculations, solar system chaos limits how far back astronomical calculations can be performed with confidence. High-resolution paleoclimate records with Milankovitch imprints now allow reversing the traditional cyclostratigraphic approach: Middle Eocene drift sediments from Newfoundland Ridge are well-suited for this purpose, due to high sedimentation rates and distinct lithological cycles. Per contra, the stratigraphies of Integrated Ocean Drilling Program Sites U1408-U1410 are highly complex with several hiatuses. Here, we built a two-site composite and constructed a conservative age-depth model to provide a reliable chronology for this rhythmic, highly resolved (<1 kyr) sedimentary archive. Astronomical components (g-terms and precession constant) are extracted from proxy time-series using two different techniques, producing consistent results. We find astronomical frequencies up to 4% lower than reported in astronomical solution La04. This solution, however, was smoothed over 20-Myr intervals, and our results therefore provide constraints on g-term variability on shorter, million-year timescales. We also report first evidence that the g 4 -g 3 "grand eccentricity cycle" may have had a 1.2-Myr period around 41 Ma, contrary to its 2.4-Myr periodicity today. Our median precession constant estimate (51.28 ± 0.56″/year) confirms earlier indicators of a relatively low rate of tidal dissipation in the Paleogene. Newfoundland Ridge drift sediments thus enable a reliable reconstruction of astronomical components at the limit of validity of current astronomical calculations, extracted from geologic data, providing a new target for the next generation of astronomical calculations.

Cyclostratigraphy and astrochronology are now at the forefront of geologic timekeeping. While this technique heavily relies on the accuracy of astronomical calculations, solar system chaos limits how far back astronomical calculations can be performed with confidence. High-resolution paleoclimate records with Milankovitch imprints now allow reversing the traditional cyclostratigraphic approach: Middle Eocene drift sediments from Newfoundland Ridge are exceptionally well-suited for this purpose, thanks to high sedimentation rates and distinct lithological cycles. Per contra, the stratigraphies of Integrated Ocean Drilling Program Sites U1408-U1410 are highly complex with several hiatuses. Here, we build a two-site composite and construct a conservative age-depth model to provide a reliable chronology for this rhythmic, highly-resolved (<1 kyr) sedimentary archive. Astronomical components (g-terms and precession constant) are extracted from proxy time-series using two different techniques, nevertheless producing similar results. We find astronomical frequencies up to 4% lower than reported in astronomical solution “La04”. This solution, however, was smoothed over 20-Myr intervals, and our results therefore provide constraints on g-term variability on shorter, million-year timescales. We also report first evidence that the g4-g3 “grand eccentricity cycle” may have had a 1.2-Myr period around 41 Ma, contrary to its 2.4-Myr periodicity today. Our median precession constant estimate (51.28 ± 0.56”/year) confirms earlier indicators of a relatively low rate of tidal dissipation in the Paleogene. Newfoundland Ridge drift sediments thus enable a reliable reconstruction of astronomical components at the limit of validity of current astronomical calculations, extracted from geologic data, providing a new target for the next generation of astronomical calculations.

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