Abstract Beach stratigraphy at North Beach, Sandy Hook, New Jersey is used to calibrate a model of coastal erosion, establish a model‐based erosion threshold, and evaluate how often threshold conditions have been exceeded since 1979 through hindcast analysis. Ground penetrating radar (GPR) was used to identify 20 stratigraphic surfaces generated in response to storm‐driven erosion, and centimeter‐accurate GNSS data were used to constrain their formation between 2009 and 2019 CE. To quantify the forcing conditions generating the preserved erosion surfaces, we ran more than 1000 48‐hr XBeach simulations using tide‐gauge and offshore wave buoy data. We then statistically emulated the XBeach output and calibrated it with observed beach‐profile change using a semi‐empirical model that we used to identify the storms most likely to have produced the preserved erosion surfaces. The modeling results suggest storms exceeding a water‐level threshold of 1.3 m above MSL and significant wave heights of 3.8 m resulted in significant coastal erosion. Analysis of hindcast wave conditions and water‐level data suggests an approximately two‐fold increase in the exceedance frequency of this storm threshold between 1979 and 2023 CE. The inferred erosion threshold is tested using pre‐, during‐, and post‐event observations from a recent 10 January 2024 storm that exceeded threshold conditions. We assess that beach stratigraphy is underutilized for the study of impacts and frequency of coastal storms that cause significant erosion, and our results demonstrate how model‐data integration can be used to broaden inferences made from stratigraphic data.

We model Cenozoic temperature and ice volume changes using the Pacific benthic δ 18 O record and a global compilation of foraminiferal Mg/Ca data. In our model, the proportion of δ 18 O benthic variation reflecting temperature change over time is parameterized, and a benthic foraminiferal paleotemperature equation is used to estimate δ 18 O sw . Barystatic sea level (BSL) is derived using an ice-sheet model that defines temporal variability in the ratio of δ 18 O sw to BSL change. We calibrate parameters to align model output BSL and temperature variations with independent sea-level estimates and Mg/Ca-derived temperatures. Our approach is conceptually similar to previous efforts to decompose δ 18 O benthic using Mg/Ca data as temperature constraint, but differs through our application of the ice-sheet model and a Bayesian inversion framework. Our results indicate a modestly sized Antarctic ice sheet is present through most of the Paleocene and Early Eocene. Large Antarctic and modest Northern Hemisphere ice sheets (NHIS) developed after the Eocene-Oligocene transition, though the NHIS melted during most interglacial periods and through the Miocene Climate Optimum. Milankovitch forcing produced 100 kyr BSL variability that increased from ~5 m in the Paleocene to 30–40 m through the Oligocene and Early to early Middle Miocene, before diminishing to 20–30 m in the late Middle to Late Miocene. The amplitude rose again to ~40 m in the Early Pliocene and has increased to 80–100 m 100 kyr over the past Myr. Constructive interference of precession, obliquity, and eccentricity produces large variations in deep sea paleotemperature and BSL, especially at a ~100 kyr periodicity.

We map the spatial and temporal distribution and depositional environments of Eocene sequences and formations in the New Jersey Coastal Plain, USA, using an array of coreholes and gamma logs. On this passive margin, Eocene depositional systems reflect a change from prograding earliest Eocene mud lobes, to early to middle Eocene hemipelagic ramp, and finally to late middle Eocene prograding sandy sequences. The Marlboro Clay, containing the Paleocene-Eocene Thermal Maximum (PETM), was deposited as prograding fluid mud during times of high global temperatures; it is found in northern and southern lobes but is absent from the central coastal plain. Lower and lower middle Eocene sediments consist of carbonate-rich clays ("marls") deposited in middle to outer neritic (50-150 m) paleodepths on a hemipelagic ramp during a peak in global mean sea level. Exceptionally deep early Eocene deep water depths compared to other regions are attributed to mantle dynamic topography. The upper middle to upper Eocene consists of three prograding lithologic units found in parallel belts with coarse-grained sediments in the most updip positions and fine-grained sediments found in the most downdip positions; the lithologic units transgress time and sequences. Comparison of the timing of sea-level falls constructed using oxygen isotopes with New Jersey Eocene sequence boundaries shows a correlation between sequences boundaries and global mean sea-level falls controlled by ice-volume changes, even in the purportedly ice-free early Eocene. We date the change from ramp to prograding sequences to the late middle Eocene (ca. 41.5 Ma). We use a forward stratigraphic model to evaluate the primary controls influencing changing styles of sedimentation on the Eocene New Jersey margin. Our forward stratigraphic model shows that the appearance of prograding sands and silts in the middle Eocene is a response primarily to changes in siliciclastic input, presumably due to climate or tectonics in the hinterland. Our study of the New Jersey Eocene shows that by integrating stratigraphic and chronostratigraphic data with an independent estimate of global mean geocentric sea level, our forward model was able to disentangle the effects of sea level and sediment supply on the stratigraphic record.

We evaluate lead-lag relationships between warming associated with the Paleocene-Eocene thermal maximum (PETM) and the attendant carbon isotope excursion (CIE) recorded in sedimentary archives from the mid-Atlantic continental margin. Cores from the New Jersey coastal plain (NJCP) provide thick (up to 15 m), rapidly deposited shelf PETM sections recording a 6-8 degrees C warming based on the TEX86 paleothermometer. Updip cores from Medford, NJ provide the most expanded CIE onset, associated with a gradual lithologic change from uppermost Paleocene glauconitic sands to the lowermost Eocene kaolinitic Marlboro Clay. The relative thickness of these transitional sediments and the CIE onset allow for high-resolution stable isotopic (bulk sediment, foraminifera, and organic carbon) and lipid biomarker analyses. The TEXH86-derived temperature records from Medford cores show no warming prior to the CIE onset, with the carbon isotopic decrease in phase with temperature. Previous studies of more downdip PETM sections on the NJCP suggested that warming preceded the CIE, consistent with a thermal trigger for carbon release. Re-evaluation of published records and Bayesian analysis of TEXH86-derived temperature and delta 13C from five NJCP sites do not indicate a statistically discernible lead or lag of carbon injection and warming. Though we can not preclude that a lead or lag exists, our analysis suggests that a synchronous CIE onset and warming is the most likely scenario on the NJ paleoshelf.

The presence and suitability of carbon storage reservoirs in the Georges Bank Basin (GBB; offshore Massachusetts) is evaluated through the application of sequence stratigraphy and the construction of a static earth model using those interpretations and physical properties measurements. Sequence stratigraphy is applied using well logs and similar to 60,000 km (similar to 37,200 mi) of multichannel seismic profiles to delineate six thick (>100 m [>330 ft]) Lower Cretaceous fluvial-deltaic depositional sequences. Two composite Missisauga sequences (MS2 and MS1; Berriasian to Barremian) comprise the lowermost prospective storage resource that may store 4.2-8.4 Gt (2% and 4% efficiency factors) of supercritical CO2 beneath the confining Naskapi shale. These heterolithic, fluvial sandstones comprise thinner and less laterally expansive sand bodies than the deltaic sandstones within three overlying Logan Canyon sequences (LC3, LC2, and LC1; Aptian to Upper Cenomanian). The Logan Canyon sequences comprise a prospective storage resource of 9.7-19.5 Gt sealed by the overlying Dawson Canyon shale. Combined, these Lower Cretaceous strata represent storage resources of similar to 14 to 28 Gt in the GBB. The 38-76 Gt of total reservoir resources in Lower Cretaceous sandstones in the Baltimore Canyon Trough to the south, coupled with a closer proximity to emissions sources and better refinement of reservoir characterization for those strata, renders the GBB an unlikely location for initial adoption of offshore carbon capture and storage (CCS) regionally. However, storage resources in the GBB are of significant value if CCS is to be adopted at a scale impactful to mitigating the effect of anthropogenic emissions on atmospheric CO2 concentrations.

We estimate ice-volume driven (barystatic; BSL) sea-level changes for the Cenozoic using new Mg/Ca data from 58 to 48 Ma and a revised analysis of Mg/Ca trends over the past 66 Myr. We combine records of BSL, temperature-driven sea level, and long-term ocean basin volume variations to derive a new global mean geocentric sea level (GMGSL; “eustatic”) estimate. Bayesian analysis with Gaussian process priors shows that our BSL estimate shares a component that covaries on the Myr scale with “backstripped” relative sea-level (RSL) estimates (accounting for compaction, loading, and thermal subsidence) from the US Mid-Atlantic Coastal Plain, validating our method and estimates with errors of ±10 m. Peak warmth, elevated GMGSL and BSL, high CO2, and ice-free conditions occurred at times in the Paleocene to Eocene (ca. 64, 57.5, 35 Ma) and in much of the Early Eocene (55–48 Ma). However, our new results show that the Early Eocene was punctuated at specific times by several Myr-scale sea level lowerings (∼20–40 m) that require growth and decay of significant continental ice sheets even in the supposedly “ice-free” world. Continental-scale ice sheets waxed and waned beginning ca. 34 Ma (>50 m BSL changes), with near complete collapse during the Miocene Climate Optimum (17–14.8 Ma). Both the BSL and RSL estimates have markedly higher Oligocene to Early Miocene Myr-scale amplitudes (20–60 m) than recently published δ18O-based estimates (<20 m) and much lower estimates than those of Exxon Production Research (>100 m), leading us to reject those estimates. The US Mid-Atlantic margin RSL was dominated by GMGSL but was overprinted by changes in mantle dynamic topography on the several Myr scale, showing approximately 50 m higher Eocene estimates and regionally propagating Miocene RSL changes.

We examined Holocene benthic foraminiferal biofacies, % planktonic foraminifera, and lithofacies changes from New England mud patch cores and present a relative sea-level (RSL) record to evaluate evolution of these rapidly deposited (30 - 79 cm/kyr) muds. Sandy lower Holocene sections are dominated by Bulimina marginata . The mud patch developed from 11 - 9 ka as RSL rise slowed from 10 to 7 mm/yr; mud deposition began when the cores (69 to 91 m modern) were inundated below storm wave base. An Elphidium-B. marginata fauna developed at ca. 7 - 6 ka as RSL rise slowed from approximately 7 to 2 mm/yr. A Globobulimina fauna developed at 3 ka as RSL rise slowed to 1 mm/yr, re flecting lower O-2 conditions. Single specimen delta (18) O analyses of Globobulimina show similar to 1% variations over the past 3 kyr, reflecting a shelf bottom water seasonal cycle of 4 - 5 degrees C, and a temperature minimum during the Little Ice Age with warming since.

The release of over 4500 Gt (gigatonnes) of carbon at the Paleocene–Eocene boundary provides the closest geological analog to modern anthropogenic CO2 emissions. The cause(s) of and responses to the resulting Paleocene–Eocene Thermal Maximum (PETM) and attendant carbon isotopic excursion (CIE) remain enigmatic and intriguing despite over 30 years of intense study. CIE records from the deep sea are generally thin due to its short duration and slow sedimentation rates, and they are truncated due to corrosive bottom waters dissolving carbonate sediments. In contrast, PETM coastal plain sections along the US mid-Atlantic margin are thick, generally having an expanded record of the CIE. Drilling here presents an opportunity to study the PETM onset to a level of detail that could transform our understanding of this important event. Previous drilling in this region provided important insights, but existing cores are either depleted or contain stratigraphic gaps. New core material is needed for well-resolved marine climate records. To plan new drilling, members of the international scientific community attended a multi-staged, hybrid scientific drilling workshop in 2022 designed to maximize not only scientifically and demographically diverse participation but also to protect participants' health and safety during the global pandemic and to reduce our carbon footprint. The resulting plan identified 10 sites for drill holes that would penetrate the Cretaceous–Paleogene (K–Pg) boundary, targeting the pre-onset excursion (POE), the CIE onset, the rapidly deposited Marlboro Clay that records a very thick CIE body, and other Eocene hyperthermals. The workshop participants developed several primary scientific objectives related to investigating the nature and the cause(s) of the CIE onset as well as the biotic effects of the PETM on the paleoshelf. Additional objectives focus on the evidence for widespread wildfires and changes in the hydrological cycle, shelf morphology, and sea level during the PETM as well as the desire to study both underlying K–Pg sediments and overlying post-Eocene records of extreme hyperthermal climate events. All objectives address our overarching research question: what was the Earth system response to a rapid carbon cycle perturbation?

We produced a 10 Myr synthetic stratigraphic section using a forward stratigraphic model that generates marine deltaic stratigraphy over geological timescales. We recursively fit the model using a Bayesian inversion algorithm to test: (1) if it could be accurately reconstructed; (2) if the parameters used to create it could be recovered; and (3) the sensitivity of the model output to given model parameters and the attendant physical processes. The original synthetic stratigraphic section was produced with cyclical sea-level variations of 40 and 30 m with 2.4 and 10 Myr periods respectively. Sediment was also supplied cyclically, in 2.4 and 10 Myr cycles with amplitudes of 30 and 80 tons/100 kyr, respectively, varying from a mean of 232 tons/100 kyr. Parameter values were sampled to fit the model using a Markov chain Monte Carlo algorithm, resulting in a ±5 m (1σ) variation between the experimental output and the original. Sea level varied by ±7 m (1σ) within the posterior distribution of parameters. As a result, both the 10 Myr and 2.4 Myr sea-level cycles could be extracted from the original output. The variation in sediment supply was approximately ±38 tons/100 kyr (1σ) and, as a result, only the larger long-term supply variations could be accurately recovered in refitting the model. The variation in thermal, flexural and total subsidence across those parameter sets is less than ±10 m (1σ). The original section experienced 150 m of total subsidence at the depocentre. Our results demonstrate the distinct and interpretable imprint of sea level and subsidence on continental margin stratigraphy can be quantified. Moreover, we conclude that sea-level change produces a defined effect on the geometries of stratigraphic architecture, and that techniques applied for the purpose of delineating sea-level variation from continental margin strata have a well-founded conceptual basis.

We produced a 10 Myr synthetic stratigraphic section using a forward stratigraphic model that generates marine deltaic stratigraphy over geological timescales. We recursively fit the model using a Bayesian inversion algorithm to test: (1) if it could be accurately reconstructed; (2) if the parameters used to create it could be recovered; and (3) the sensitivity of the model output to given model parameters and the attendant physical processes. The original synthetic stratigraphic section was produced with cyclical sea-level variations of 40 and 30 m with 2.4 and 10 Myr periods respectively. Sediment was also supplied cyclically, in 2.4 and 10 Myr cycles with amplitudes of 30 and 80 tons/100 kyr, respectively, varying from a mean of 232 tons/100 kyr. Parameter values were sampled to fit the model using a Markov chain Monte Carlo algorithm, resulting in a +/- 5 m (1 sigma) variation between the experimental output and the original. Sea level varied by +/- 7 m (1 sigma) within the posterior distribution of parameters. As a result, both the 10 Myr and 2.4 Myr sea-level cycles could be extracted from the original output. The variation in sediment supply was approximately +/- 38 tons/100 kyr (1 sigma) and, as a result, only the larger long-term supply variations could be accurately recovered in refitting the model. The variation in thermal, flexural and total subsidence across those parameter sets is less than +/- 10 m (1 sigma). The original section experienced 150 m of total subsidence at the depocentre. Our results demonstrate the distinct and interpretable imprint of sea level and subsidence on continental margin stratigraphy can be quantified. Moreover, we conclude that sea-level change produces a defined effect on the geometries of stratigraphic architecture, and that techniques applied for the purpose of delineating sea-level variation from continental margin strata have a well-founded conceptual basis. Modelledstratigraphy reconstructed using Bayesian inversion. The top panels show the reconstructedstratigraphy (panel a) and a wheeler diagram of this model output (panel b). Thethree other panels show the original and reconstructed values of: 1) flexure,thermal subsidence, and total subsidence (panel c); 2) sea-level change (paneld); and 3) sediment supply variations (panel e). The greater variability in theposterior distribution of sediment supply values relative to those for sealevel suggests that the development of passive continental margin stratigraphic architecture is particularlysensitive to sea-level variation.image

Glauconite is the name of a mineral and soil containing significant quantities of iron and potassium varying in color from green to black, linked to its geological history. These soils are problematic in nature and exhibit potentially hazardous responses related to the construction of foundations. This is in part due to the difficulties in quantifying their geotechnical properties and how easily these properties change. Sand-sized glauconitic particles are often fractured, which increases their crushability, transitioning from sand-sized to fine-grained particles with cohesive behavior. This has led to geotechnical challenges including difficulty in pile driving and the potential for refusal. Glauconite has been shown to adhere to pile walls, which increases pile driving resistance. This may be a problem as glauconite deposits can be found along the eastern coast of the US in offshore wind lease areas. In this study, two glauconitic sands from the East Coast of the US are investigated for differences in their Atterberg limits in their natural and crushed state to quantify the increases of plasticity. Results on samples from the Late Cretaceous Navesink and Paleogene Hornerstown formations illustrate how sample preparation and particle crushing increases plasticity and changes USCS classification of glauconite soils. Additionally, it was found that these specific soils are acidic and when crushed their acidity levels and their colors can change.

Glauconite sand is a challenging sediment that can pose risks to foundation installation and performance due to its tendency to transform from coarse-grained material into fine-grained material due to particle crushing. Glauconite is characteristically green iron potassium mica and smectite often found in sand-sized peloidal form. It forms under reducing conditions within marine depositional environments below wave base and has been found in coastal plain and offshore regions of the U.S. This paper presents an overview of the geological basis for glauconite sand formation, describes its depositional environment and maturation process, and summarizes the state of knowledge of geotechnical challenges in glauconite sands. Laboratory test results are presented for glauconite sands collected from the U.S. Atlantic coastal plain, showing that initial sample conditions, drying methods, and degradation methods affect the initial, temporary, and long-term geochemical and mechanical characteristics of glauconite sands. The degree to which particles crush or degrade from their natural peloidal form to clay-size particles is linked to maturity and depositional method. Intentionally degraded specimens used in laboratory testing can simulate the effect of pile driving through creation of a shear zone of degraded soil along the pile shaft, and quantify its impact on soil-structure interface strength.

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 radiography, natural gamma ray, density, magnetic susceptibility, and X-ray fluorescence (XRF). A full suite of downhole logs was also run. Intervals of organic carbon enrichment occur in the Rhaetian (Late Triassic) Westbury Formation and in the earliest Hettangian and earliest Pliensbachian strata of the Redcar Mudstone Formation, where up to 4 % total organic carbon (TOC) is recorded. Other parts of the succession are generally organic-lean, containing less than 1 % TOC. Carbon-isotope values from bulk organic matter have also been determined, initially at a resolution of ∼ 1 m, and these provide the basis for detailed correlation between the Prees 2 succession and adjacent boreholes and Global Stratotype Section and Point (GSSP) outcrops. Multiple complementary studies are currently underway and preliminary results promise an astronomically calibrated biostratigraphy, magnetostratigraphy, and chemostratigraphy for the combined Prees and Mochras successions as well as insights into the dynamics of background processes and major palaeo-environmental changes.

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.