Today, ocean circulation is characterized by southward-flowing North Atlantic Deep Water and northward-flowing Antarctic Bottom Water, with a mixture of water masses filling the Pacific and Indian Oceans. Also, a Southern Hemisphere supergyre (i.e., an inter-basin wind-driven current) facilitates exchange of water among South Pacific, Indian, and South Atlantic Oceans subtropical gyres. The ocean circulation in the Eocene was different. Here we present new benthic foraminiferal oxygen and carbon stable isotopes (delta O-18(bf) and delta C-13(bf)) from Ocean Drilling Program (ODP) Site 1090 (Agulhas Ridge) spanning the middle and early late Eocene that extend a published late Eocene-early Oligocene record (Pusz et al., 2011, https://doi.org/10.1029/2010pa001950) into a time characterized by the evolution of the Drake Passage and Tasman Gateway. The comparison of the Site 1090 combined data set with delta O-18(bf) and delta C-13(bf) from the Southern, Atlantic, and sub-Antarctic Indian Oceans confirms the presence of a water mass with higher delta O-18(bf) at depths <2,000 m and a water mass with lower delta O-18(bf) at depths >2,000 m, as already reported. We interpret these signals to be evidence of a deep supergyre at depths <2,000 m transporting salty higher delta O-18(bf) waters originating from the Indian Ocean into the Southern and eastern South Atlantic Oceans. Cold waters that formed around Antarctica spread northward, bathing sites >2,000 m. As the Drake Passage and Tasman Gateways opened and deepened and the Antarctic Circumpolar Current developed, deep-water formation became more prominent at higher latitudes, while the supergyre became restricted to shallower depths.

Benthic foraminiferal Mg/Ca, Sr/Ca, B/Ca, and Mg/Li data are used to reconstruct deep‐sea temperature and seawater carbonate chemistry. However, the concurrent influence of various environmental parameters on these proxies is not fully understood. Here, we compile published and unpublished element/Ca core‐top data from Cibicidoides mundulus , C. pachyderma, Lobatula wuellerstorfi , Oridorsalis umbonatus , Nuttallides umbonifera , and Uvigerina spp. to determine the sensitivity of these species' Mg/Ca, Sr/Ca, B/Ca, and Mg/Li to temperature, calcite saturation state (Ω calcite ), dissolved inorganic carbon (DIC), and salinity. By applying multivariate linear regression analysis, we disentangle the effects of these environmental parameters on these species element/Ca. Based on this, we provide multivariate element/Ca calibrations with temperature and Ω calcite sensitivities for all species‐elemental system combinations. Overall, our analysis reveals that: (a) the Mg/Ca‐sensitivity to temperature is substantially lower compared to most previous approaches when accounting for the effect of Ω calcite ; (b) Sr/Ca is driven dominantly by Ω calcite ; (c) B/Ca can be linearly related to Ω calcite ; and (d) Mg/Li‐temperature calibrations have substantially lower degrees of unexplained variance compared to Mg/Ca. Our calibrations offer a statistically robust approach that also allows us to quantify the uncertainties in the reconstruction of temperature and carbonate chemistry when these element/Ca proxies are used. Finally, we present user‐friendly data processing software (“ElCaRBenthic”) that can simultaneously solve up to two benthic foraminiferal element/Ca data sets for temperature and Ω calcite (e.g., Mg/Ca and Sr/Ca), while providing the ability to correct for long‐term changes in seawater elemental chemistry and propagating all sources of uncertainty.

The bforams@mikrotax database focuses on deep-sea foraminifera from the Cretaceous through Cenozoic, providing a comprehensive, universally accessible taxonomic resource. Based on nannotax and pforams@mikrotax, this database provides an easy-to-use website for experts, researchers, and early career scientists, promoting stability in identifications and nomenclature. By providing detailed descriptions, images, citations, and expert opinions, bforams@mikrotax is becoming a crucial tool for paleoenvironmental, paleoceanographic, paleoclimatic, biostratigraphic, paleobiological studies, and foraminiferal geochemical analyses. The "Main Catalog" provides monographic coverage of 1,600 key taxa, including lists of junior synonyms, updated primary and secondary type images, morphological descriptions, paleobathymetry, and graphical stratigraphic range bars. The "Original Description Catalog" includes information from the original species designations, type specimen repository and locality information, and images of the primary type specimens. The bforams@mikrotax database will provide an invaluable research, reference, and teaching tool for students and researchers across all levels of expertise.

The latest Triassic was characterised by protracted biotic extinctions concluding in the End-Triassic Extinction (~ 200 Ma) and a global carbon cycle perturbation. The onset of declining diversity is closely related to reducing conditions that spread globally from upper Sevatian (uppermost Norian) to across the Norian-Rhaetian boundary, likely triggered by unusually high volcanic activity. We correlate significant organic carbon cycle perturbations to an increase of CO2 in the ocean–atmosphere system, likely outgassed by the Angayucham igneous province, the onset of which is indicated by the initiation of a rapid decline in 87Sr/86Sr and 188Os/187Os seawater values. A possible causal mechanism involves elevated CO2 levels causing global warming and accelerating chemical weathering, which increased nutrient discharge to the oceans and greatly increased biological productivity. Higher export production and oxidation of organic matter led to a global O2 decrease in marine water across the Norian/Rhaetian boundary (NRB). Biotic consequences of dysoxia/anoxia include worldwide extinctions in some fossil groups, such as bivalves, ammonoids, conodonts, radiolarians.

Abstract We investigate early Eocene hyperthermals by complementing foraminiferal and bulk carbonate isotopes with benthic foraminiferal assemblages from three marine coreholes located along a paleoshelf transect on the New Jersey coastal plain (ODP 174AX Bass River, Double Trouble, and Ancora). Distinct negative δ13C and δ18O excursions likely correspond to the globally documented ETM-2, H2, I1, I2, and J events. Foraminiferal stable isotope data at Bass River reveal greater warming in benthic and thermocline communities compared to the surface dwellers during these excursion events. During the largest excursion event (ETM-2), thermocline-dwelling Subbotina not only experienced greater overall warming, but also recorded lower δ18O values than Morozovella (–5.1‰ vs. –4.3‰). This suggests either greater warming in the thermocline, habitat depth restructuring, or possibly a change in calcification season. We also demonstrate a potential biotic threshold, providing the first comprehensive evaluation of the sensitivity of shallow-marine taxa in response to these transient warming events.

Sedimentary records show that calcium carbonate (CaCO3) preservation fluctuated during the Eocene. These fluctuations are well documented for the equatorial Pacific. However, data from other basins are sparse. In this study, we report new middle and late Eocene bulk calcium carbonate percentages and accumulation rates from the northwestern Pacific (Ocean Drilling Program-ODP-Site 884) and the Atlantic (ODP Sites 1053, 1090, and 1263) Oceans; in addition, we calculate CaCO3 accumulation rates for sites with published percentage bulk CaCO3 to expand geographic and paleobathymetric coverage. Using these data, we investigate the response of the carbonate cycle to environmental changes (e.g., temperatures, primary productivity, weathering, and ocean circulation) at the beginning of the greenhouse-icehouse transition (similar to 43-34 Ma). Our results show that in the middle to late Eocene CaCO3 accumulation rates were highly variable at different paleodepths and ocean basins suggesting that the evolution of carbonate accumulation rates over the Eocene was influenced by different processes in different locations. In particular, our data emphasize the role of surface CaCO3 production and ocean ventilation in driving changes in CaCO3 preservation and burial at the seafloor. Our study also highlights the need for a better understanding of the processes regulating CaCO3 surface production today in order to correctly interpret geological records.

The latest Triassic was an interval of prolonged biotic extinction culminating in the end-Triassic Extinction (ETE). The ETE is now associated with a perturbation of the global carbon cycle just before the end of the Triassic that has been attributed to the extensive volcanism of the Circum-Atlantic Magmatic Province (CAMP). However, we attribute the onset of declining latest Triassic diversity to an older perturbation of the carbon cycle (δ13Corg) of global extent at or very close to the Norian/Rhaetian boundary (NRB). The NRB appears to be the culmination of stepwise biotic turnovers that characterize the latest Triassic and includes global extinctions of significant marine and terrestrial fossil groups. These biotic events across the NRB have been largely under-appreciated, yet together with a coeval disturbance of the carbon cycle were pivotal in the history of the Late Triassic. Here, we present new and published δ13Corg data from widespread sections (Italy, Greece, ODP, Australia, New Zealand, USA, Canada). These sections document a previously unknown perturbation in the carbon cycle of global extent that spanned the NRB. The disturbance extended across the Panthalassa Ocean to both sides of the Pangaean supercontinent and is recorded in both the Northern and Southern Hemispheres. The onset of stepwise Late Triassic extinctions coincides with carbon perturbation (δ13Corg) at the NRB, indicating that a combination of climatic and environmental changes impacted the biota at a global scale. The NRB event may have been triggered either by gas emissions from the eruption of a large igneous province pre-dating the NRB, by a bolide impact of significant size or by some alternative source of greenhouse gas emissions. As yet, it has not been possible to clearly determine which of these trigger scenarios was responsible; the evidence is insufficient to decisively identify the causal mechanism and merits further study.

Sediment surface death assemblages of recent testate amoebae (Arcellacea) are reported from nine sites in Lake Superior and Lake Michigan. These are the first profundal sediment-water interface samples of testate amoebae described from either of the Great Lakes which provide valuable insight on deep-water, large-lake assemblages. Centropixid strains were present to abundant in shallower, nearshore sites (up to 66 m water depth). Assemblages at depths >40 m were dominated by Difflugia oblonga "tenuis." The shallowest sample (26 m) was dominated by Centropyxis aculeata "discoides" and Difflugia oblonga "tenuis." Over 100 tests per sample were observed from >100 m. Density of tests appears to be constrained by lithology rather than water depth. The deepest site (325 m) yielded low foraminiferal abundances. This pilot study provides a first step towards documenting the distribution of testate amoebae in the Great Lakes.

AbstractWe report 40Ar‐39Ar step‐heating ages of Paleocene‐Eocene (P‐E) boundary impact spherules from Atlantic Margin coastal plain and open ocean sites. We test the hypothesis that the P‐E spherules are reworked from an earlier event (e.g., K‐Pg impact at ~66 Ma), which predicts a cooling age discordant from their depositional age of 55.93 ± 0.05 Ma at the P‐E boundary. Isochrons from the step‐heating analysis yield 40Ar‐36Ar intercepts in excess of the modern in most cases, indicating that the spherules have excess radiogenic Ar (40Ar*), typical of impact glasses incompletely degassed before solidification. The weighted mean of the isochron‐corrected plateau age is 54.2 ± 2.5 Ma (1σ), and their isochron age is 55.4 ± 4.0 Ma, both indistinguishable from their P‐E depositional age, not supporting the K‐Pg reworking hypothesis. This is consistent with all other stratigraphic and geochemical evidence for an impact at the P‐E boundary and ejecta distribution by air fall.

Micropaleontological faunal studies coupled with foraminiferal geochemical analyses from the Bass River Site (Ocean Drilling Program [ODP] Leg 174AX; New Jersey, USA) reveal rapid changes in relative sea level due to million-year-scale glaciations during the early to middle Eocene, a time previously thought to have been mainly ice free. We examine benthic foraminiferal assemblages, stable isotopes (δ18O and δ13C), Mg/Ca, planktonic foraminiferal abundances, and ostracod abundances in eight lower to middle Eocene sequences at Bass River to reconstruct paleo–water depth and paleoceanographic changes within a sequence stratigraphic framework on the New Jersey paleo–continental shelf. Distinct benthic foraminiferal biofacies are identified and interpreted for paleodepth and environmental changes. Certain dominant species (e.g., Uvigerina spp., Cibicidoides eocaenus, Spiroplectammina alabamensis, Siphonina claibornensis, and Cibicidoides pippeni) indicate changes in water depth and/or environmental conditions. We estimate middle to outer neritic (50–100+ m) paleodepths for much of the early to middle Eocene, with maximum water depths (~150 ± 25 m) occurring in the early Eocene. We integrate these results with ostracod abundances and diversity, planktonic foraminiferal abundances, lithofacies, downhole logs, and core erosional surfaces to create a sequence framework for the early Eocene to early late Eocene of the New Jersey coastal plain. We compare the relationships among these sequences to foraminiferal biofacies of coreholes of the New Jersey Coastal Plain Drilling Project (Island Beach, Atlantic City, and ACGS#4), showing coeval hiatuses associated with regional base-level lowerings. Benthic and planktonic foraminifera δ18O coupled with low-resolution Mg/Ca measurements provide a first-order correlation of sequence boundaries and δOseawater variations, indicating glacioeustatic changes associated with the growth and decay of small ice sheets on the order of 20–30 m sea-level equivalent during the Eocene. INTRODUCTION The cause of eustatic changes has been widely debated (e.g., Moucha et al., 2008). Global mean sea level (GMSL) is controlled by fluctuations in either the ocean basin size or the volume of water in the ocean (e.g., Miller et al., 2005a), whereas relative sea level (RSL) is described by changes in accommodation space due to changes in (1) GMSL and/or (2) subsidence and/or uplift (Posamentier and Vail, 1988). The growth and decay of continental ice sheets produces rapid and large-scale changes in the volume of water (up to 40 m/k.y. and 200 m respectively), whereas water temperature and variations in groundwater and lake storage occur at high rates (10 m/k.y.) yet low amplitudes (~5–10 m) (e.g., Miller et al., 2005a). Fluctuations in ocean basin volume are controlled by slow (>1 m.y.) variations in sea-floor spreading rates, sedimentation, and continental collision (e.g., Miller et al., 2005a). Therefore, the only known mechanism that can explain large (>25 m) and rapid (<1 m.y.) changes in GMSL is the growth and decay of ice sheets (glacioeustasy). Glacioeustasy in a Greenhouse World The onset of continent-wide Antarctic glaciation occurred around the Eocene-Oligocene transition (EOT) and is marked by a prominent δ18O increase at 34–33.5 Ma (e.g., Kennett and Shackleton, 1976; Miller et al., 1991, 2008; Zachos et al., 1996; Coxall et al., 2005; Katz et al., 2008; Lear et al., 2008; Carter et al., 2017). The EOT is associated with a fall of atmospheric CO2 (e.g., DeConto and Pollard, 2003a; Pearson et al., 2009; Pagani et al., 2005, 2011) and/or a change in ocean circulation (e.g., Exon et al., 2004; Stickley et al., 2004; Scher and Martin, 2006; Livermore et al., 2007; Borrelli et al., 2014). In the first scenario, cooling caused by falling pCO2 allowed snow to accumulate and ice sheets to expand over Antarctica at high elevations (e.g., DeConto and Pollard, 2003a). In the second scenario, the opening of two gateways resulted in the development of the Antarctic Circumpolar Current (ACC) and led to Antarctic glaciation: (1) the Drake Passage, which isolated Antarctica from South America (Scher and Martin, 2006; Livermore et al., 2007); and (2) the Tasman Rise, which isolated Antarctica from Australia (Exon et al., 2004; Stickley et al., 2004). Although there is a consensus for the glaciation of much, if not all, of the Antarctic continent in the Oligocene, the period leading up to Antarctic glaciation remains poorly constrained. The overall cooling trend that led to the EOT began following the sustained warming period of the Early Eocene GEOSPHERE GEOSPHERE, v. 15, no. 2 https://doi.org/10.1130/GES01652.1 14 figures; 1 table; 1 set of supplemental files CORRESPONDENCE: fungm3@rpi.edu; megankfung @gmail.com CITATION: Fung, M.K., Katz, M.E., Miller, K.G., Browning, J.V., and Rosenthal, Y., 2019, Sequence stratigraphy, micropaleontology, and foraminiferal geochemistry, Bass River, New Jersey paleoshelf, USA: Implications for Eocene ice-volume changes: Geosphere, v. 15, no. 2, p. 502–532, https://doi.org/10.1130 /GES01652.1. Science Editor: Raymond M. Russo Associate Editor: Cinzia Cervato Published online 19 February 2019 This paper is published under the terms of the CC-BY-NC license. © 2019 The Authors Received 21 December 2017 Revision received 11 October 2018 Accepted 9 January 2019 Downloaded from https://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/4663947/502.pdf by guest on 31 October 2019

Discovery of impact spherules associated with the onset of the Carbon Isotope Excursion (CIE) that marks the Paleocene-Eocene (P-E) boundary (similar to 56 Ma) indicates that the P-E transition was coincident with an extraterrestrial impact. Charcoal abundances increase >20 times background immediately above the P-E spherule layer at two Atlantic Coastal Plain palaeo-continental shelf localities located >200 km apart. Individual charcoal shards (similar to 100 mu m long; 58-83 wt. % carbon) show charred plant features. the carbon isotope ratio of charcoal (delta C-13(charcoal)) through the peak shows that it originated from pre-impact vegetation that burned. We consider two scenarios to explain this widespread, synchronous increase in charcoal at the P-E boundary: 1) warming-induced, continental-scale drying; and 2) impact-induced wildfires. Differentiating between these two hypotheses depends critically on the observed sequence of events, which on the western North Atlantic margin is: the impact spherule horizon, followed by the peak in charcoal (derived from vegetation that grew before the CIE and impact), and finally the nadir of the CIE. Importantly, the pre-excursion delta C-13(charcoal) remains constant through the CIE onset, requiring a dramatic increase in sedimentation. This work clarifies our understanding of the timing and sequence of events following an extraterrestrial impact at the P-E boundary.

We present a summary of previously published Olenekian–Anisian boundary magnetostratigraphic and biostratigraphic results from the Kçira area of northern Albania. We focus on the stratigraphically complete Kçira-A section that represents a potential candidate Global Boundary Stratotype Section and Point (GSSP) for the base of the Anisian Stage of the Triassic System. The previously published conodont biostratigraphy from Kçira-A and ancillary sections located nearby has been updated using modern taxonomic criteria and correlated to the available ammonoid and benthic foraminifera biostratigraphy. Previously published magnetobiostratigraphic data reveal the occurrence at Kçira-A, and ancillary sections, of a well-defined magnetic polarity reversal pattern of primary origin that allows global correlations ensuring the exportability of biostratigraphic datums (e.g., the first occurrence of conodont Chiosella timorensis) falling close to the Kclr/Kc2n polarity transition. A suite of pilot samples has also been studied for bulk carbon and oxygen isotopes stratigraphy, yielding reasonable values that suggest good preservation of primary material. These data indicate that with additional studies, Kçira-A would represent an ideal base Anisian GSSP. Research Article Published online: August 2, 2019 Muttoni, G., Nicora, A., Balini, M., Katz, M., Schaller, M., Kent, D., Maron, M., Meço, S., Rettori, R., Doda, V., & Nazaj, S.. 2019. A candidate GSSP for the base of the Anisian from Kçira, Albania. Albertiana, vol. 45, 39–49.