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We sought to develop a longer and more robust history of pollution in the Hudson River by studying LWB1-8, a high sedimentation rate core (~1 cm/yr) retrieved near Yonkers, NY. The sediment has been affected both by industrial pollution and natural disasters such as distant volcanic eruptions. In order to study this core, we analyzed its elemental composition in a variety of ways. Previous data from ITRAX scanning of the core years ago was lined up with new elemental analyses done with an XRF machine in order to pick which layers may be the most likely to contain volcanic ash. If ash particles were deemed likely in these layers, samples were run through a Franz, or magnetic materials were separated out using a Nb magnet. Then, particles of potential ash were picked out by hand. These ash candidates were then run through an SEM machine to provide a more in-depth elemental analysis of the particles as well as obtain high-resolution photos of them. Peaks in uncalibrated Ni, Ti, and SI (peaks in counts) from the ITRAK can be used to locate the depths of prospective volcanic ash layers. Ni peaks were especially good at identifying which layers may contain volcanic ash. .We found at least four layers containing volcanic ash , but there is still uncertainty about their source volcanoes. Many of the volcanic ash particles have very high Fe and very low K contents. These likely come from explosive Icelandic eruptions like those of Hekla. Other ashes have very low Fe, higher K and higher Si. These ashes likely come from volcanic arcs located at high latitudes, such as the Cascade and Aleutian arcs. This experiment has shown that it is possible to find volcanic ash in Hudson River cores. However, the number of ash particles we have retrieved so far is very small, from one to nine per age horizon. We do best at finding ash below 100 cm, where there is little industrial pollution. In future, we need to refine our methods of segregating ash from industrial debris. We must also analyze our ash particles on a microprobe and an ICPMS to determine their source volcanoes. Only then can we convert our measurements of metals versus depth into a pollution history. 

The Long Island Sound (LIS), located between Connecticut and Long Island, New York, is a crucial estuarine ecosystem that is affected by human activities in the surrounding areas. This study uses sediment grab samples from central Long Island Sound that have been collected as part of a larger habitat mapping effort in collaboration with several research groups including the Lamont-Doherty Earth Observatory of Columbia University. We determine element, and especially metal content of the sediment grab samples using x-ray fluorescence (XRF), and map their distribution in the study area, which is essential for characterizing the LIS sediment environment. By comparing the current metal contamination data with historical records, and grain size information we seek to uncover environmental changes over time. The analysis reveals an increase in metal concentrations from east to west, particularly in finegrained sediments. Historical industrial activities significantly contribute to elevated metal levels, with higher concentrations of copper and zinc observed due to restricted water circulation and industrial runoff. Other factors such as weather, human activity and ocean currents probably also influenced the detailed metal distribution. 

Cinder cones are a common feature at many volcanic eruptions. Their shapes and volumes can reveal information about eruption conditions, and their geomorphological evolution shapes them and their surrounding environment. It is thus important to quantify the rate and patterns of erosion of young cinder cones. In this study, we examine the Ahmanilix cone, which formed during the 2008 eruption of Okmok volcano in the Aleutian islands region of Alaska. Ahmanilix, located on the eastern side of Okmok’s large caldera, is >250 meters tall and characterized by dramatic gullies formed by the harsh wind, snow and rain conditions typical of the Aleutians. We usd photogrammetry to create 3D models of Ahmanilix using aerial photographic surveys taken from a helicopter in 2021, 2022, 2023 and 2024. We utilize Agisoft Metashape to build point clouds, Cloud Compare to align the point clouds and build raster Digital Elevation Models (DEMs), and QGIS and Python to visualize and analyze these products. By subtracting DEM rasters we quantify year-to-year erosion. We compare our results with erosion rates estimated from satellite observations (Dai et al., 2020), identify regions dominated by erosion or deposition and correlate them with slopes and cinder lithology. Our observations can be extended to other cinder cones and help predict their geomorphological evolution. 

Our study examines how volcanic ash layers affect Earth's environment and climate, focusing on carbon, cadmium, and sulfur changes in deep-sea sediment from the Toba super eruption 74,000 years ago. This eruption, the largest of the Quaternary period, released 2,800 cubic kilometers of material and sulfur dioxide, which formed sulfate aerosols, potentially causing a volcanic winter. In sediment core RC14-37, we found a 15 cm thick Toba ash layer at 100-115 cm depth, with the highest ash concentration at 102-104 cm, significantly diluting the sulfur signal from 102-106 cm and masking the sulfur peak. Elevated sulfur levels just below the top of the ash layer suggest rapid deposition after most ash settled, with levels decreasing towards the base, indicating additional atmospheric sulfur. We used X-ray fluorescence (XRF) to measure sulfur and cadmium content. High cadmium levels in the ash layers suggest increased marine productivity. The SiO2 content in the ash ranged from 66% to 78%. Given that Toba ash contains 12 ppm sulfur, our corrected sulfur content (1700-3100 ppm) suggests most sulfur came from atmospheric sulfate aerosols. These results indicate increased biological productivity and sulfur in the ash layers, providing insights into the eruption's ecological impacts. 

Magma ascent rate is a challenging parameter to constrain yet a crucial element to investigate magma dynamics. The 1600 eruption of the Huaynaputina volcano was the largest recorded eruption in South America, with an impact area that now hosts approximately a quarter of Peru's population. The aim of this study is to investigate the magma ascent rate of the initial Plinian phase of the eruption using pyroclast texture. Scanning electron microscopy (SEM) was employed to image several pumice clasts. The images were then cleaned and processed using the Fast Object Acquisition and Measurement System (FOAMS) to obtain a vesicle number density. Melt inclusions in crystals were identified and double polished, and their H₂O content was analyzed using infrared spectroscopy (FTIR). The mean value of the BND is 4.09×10 6 mm⁻³, while the mean value of the H₂O content is 3.05%. According to the nucleation theory, the average decompression rate is thus calculated to be 13.47 MPa/s (ascent rate of 548 m/s). An alternative equation, which relies solely on the BND, provides a decompression rate of 9.06 MPa/s (ascent rate of 362 m/s). Both calculated values are high, but remain within a reasonable range for eruptions of this magnitude. If this eruption were to occur today, it would have a catastrophic impact. These results emphasize the necessity for further research to provide a deeper understanding of such destructive eruptions. 

The purpose of this research is to investigate whether icebergs influenced the ocean’s circulation and contributed to significant climate changes during the last Ice Age. Previous studies have suggested that iceberg discharge from surrounding ice sheets introduced large volumes of freshwater into sensitive deep-water production locations in the North Atlantic Ocean, potentially altering ocean circulation and influencing regional and global climate. This research focused on the sequence of events approximately 40-50 thousand years ago in the central North Atlantic Ocean, utilizing a sediment core VM 30-100 PC recovered from the Mid- Atlantic Ridge. We quantified the abundance of ice-rafted debris (IRD) as an indicator of the presence of icebergs in the core sample from every cm at depths from 150-200 cm. In addition to IRD counting, we determined the relative abundance and stable oxygen isotope ratios (δ O) in the microfossil shells of the polar foraminifera species Neogloboquadrina pachyderma (N. pachy) as indicators of the surface ocean’s conditions during that time. By detecting an increase in δ O values over time it will indicate a decrease in ocean temperature, which we expect to correspond with a large abundance of N. pachy. Once IRD counting is completed, graphing the IRD concentration over depth will reveal periods of significant iceberg presence. By comparing the relative abundance of IRD and N. pachy in the samples, and by observing the δ O data, we aim to determine whether iceberg discharge preceded changes in ocean circulation or if sea-surface conditions shifted beforehand. Our hypothesis is that icebergs appeared first and disrupted ocean circulation, leading to subsequent changes in sea-surface conditions. This research will provide insight into the cause and sequence of natural variability in the climate system. We believe that there is a strong possibility that iceberg discharges played a crucial role in altering ocean circulation, thus driving significant climatic changes and contributing to the onset of the last Ice Age.