Abstract The Paleocene/Eocene Thermal Maximum (PETM) is characterized by pronounced global warming and associated environmental changes. In the more-or-less two decades since prior regional syntheses of Apectodinium distribution at the PETM, extensive biological and geochemical datasets have elucidated the effect of rising world temperatures on climate and the biome. A Carbon Isotope Excursion (CIE) that marks the Paleocene/Eocene Boundary is associated with an acme of marine dinocysts of the genus Apectodinium in many locations. Distinctive foraminiferal and calcareous nannofossil populations may also be present. For this updated, dinocyst-oriented view of the PETM, data from worldwide locations have been evaluated with an emphasis on stratigraphic and sedimentological context. What has emerged is that a change in lithology is common, often to a distinctive siltstone or claystone unit, which contrasts with underlying and overlying lithotypes. This change, present in shallow marine/coastal settings and in deep-water turbidite deposits, is attributed to radical modifications of precipitation and erosional processes. An abrupt boundary carries the implication that some time (of unknowable duration) is potentially missing, which then requires caution in the interpretation of the pacing of events in relation to that boundary. In most instances an ‘abrupt’ or ‘rapid’ CIE onset can be attributed to a data gap at a hiatus, particularly in shallow shelf settings where transgression resulted from sea-level rise associated with the PETM. Truly gradational lower boundaries of the PETM interval are quite unusual and, if present, are poorly known so far. Gradational upper boundaries are more common, but erosional upper boundaries have been reported. Taxonomic changes have been made to clarify identification issues that have adversely impacted some biostratigraphic interpretations. Apectodinium hyperacanthum has been retained in Wetzeliella , its original genus. The majority of specimens previously assigned to Apectodinium hyperacanthum or Wetzeliella ( Apectodinium ) hyperacanthum have been reassigned to an informal species, Apectodinium sp. 1. Dracodinium astra has been retained in its original genus as Wetzeliella astra and is emended.

ABSTRACT The present-day ocean-climate system configuration took shape during the Miocene Epoch. Toward the end of the epoch, in the late Tortonian at ca. 8.5 Ma, there was an exceptional event: collisional disruption of an >150-km-diameter asteroid, which created the Veritas family of asteroids in the asteroid belt. This event increased the flux of interplanetary dust particles rich in 3 He to Earth and probably caused a period of increased dust in the atmosphere, with consequent alteration of global and local environmental conditions. A late Miocene 3 He anomaly likely related to the Veritas event has been registered in deep-sea sediments from Ocean Drilling Program (ODP) Site 926 (Atlantic Ocean), ODP Site 757 (Indian Ocean), and in the late Tortonian–early Messinian Monte dei Corvi section near Ancona, Italy. Here, we report the results of a study in the Monte dei Corvi section aimed to recover extraterrestrial chrome-spinel grains across the 3 He anomaly interval, as has been done for the similar late Eocene 3 He anomaly in the nearby Massignano section. In this study, three ~100 kg samples were collected from the Monte dei Corvi section: two within the 3 He peak interval and one outside the anomaly interval as a background reference sample. In total, 1151 chrome-spinel grains (>63 µm) were recovered, but based on chemical composition, none of the grains has a clear extraterrestrial origin. This supports the inference that the 3 He anomaly is indeed related to the Veritas event and not to an approximately coeval breakup of a smaller H-chondritic body in the asteroid belt, an event registered in meteoritic cosmic-ray exposure ages. Spectral studies of the Veritas asteroids indicate that they are made up of carbonaceous chondritic material. Such meteorites generally have very low chrome-spinel concentrations in the grain-size range considered here, contrary to the very chromite-rich ordinary chondrites. The terrestrial grains recovered were classified, and their composition showed that all the grains have an ophiolitic origin with no substantial compositional and distributional change through the section. The source area of the terrestrial grains was probably the Dinarides orogen.

Abstract: The deep-water Léopard gas discovery in offshore Gabon presents an opportunity to examine distal facies of the Albian Madiela and Cap Lopez Groups, which overlie the Aptian Ezanga Salt. In proximal settings, the Madiela (Azingo Formation) consists of shallow marine limestone and has sparse foraminiferal recovery. In contrast, planktonic foraminifera assemblages are typically abundant and reasonably diverse in the interbedded calcareous claystones, marls, and limestones of the distal equivalent (Namina Formation) penetrated by the Léopard discovery and appraisal wells. Five informal local planktonic foraminiferal biozones are interpreted, listed from youngest to oldest, as follows: (1) an Early Cenomanian–Late Albian Muricohedbergella delrioensis “Partial-Range Zone,” characterized by abundant Muricohedbergella delrioensis and a diverse benthic foraminiferal assemblage; (2) a Late Albian Ticinella spp. “Highest-Occurrence Zone,” defined by top Ticinella primula and Globigerinelloides bentonensis ; (3) a Late–Middle Albian Favusella spp. “Highest-Occurrence Zone,” defined by the top of common Favusella washitensis and containing the additional top of Microhedbergella pseudoplanispira; (4) the Early Albian Microhedbergella rischi “Highest-Occurrence Zone,” defined by the top of Microhedbergella rischi and associated with increased numbers of spumellarian radiolaria; and (5) the earliest Albian Microhedbergella renilaevis “Taxon Range Zone,” defined by the top of Microhedbergella renilaevis . No conclusive Late Aptian microfossil markers were observed above the top of the halite (Ezanga) at Léopard, and the Aptian palynological marker, Exesipollenites tumulus , is not observed (in situ) until within the Ezanga. Organic carbon isotopes through the studied section show a positive excursion in the M. rischi and M. renilaevis zones, which broadly correlates to the OAE-1b set of Oceanic Anoxic Events (Urbino–Paquier–Kilian–Jacob).