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1. Regional and Local Stratigraphic Markers in Three Hudson River Cores Taken Near Peekskill, New York: Core LWB 4-5

   Abdul, B.; Adeghe, S.; Diallo, M. B.; McCann, B.; Abbott, D. H.; Bostick, B. C.; Chang, C.; Block, K. A. (December 2018, American Geophysical Union, Fall Meeting 2018, abstract #B53I-2167)

   We have been studying the stratigraphy of core LWB 4-5 taken in 2001 in the Hudson River 1.5 km north of the transit of the Peekskill meteorite in October 1992. We measured magnetic susceptibility and elemental composition at 1 cm intervals down to 50 cm and then at 5 cm intervals down to 108 cm. Magnetic susceptibilities are unusually high (above 20 cgs units) from 12-19 cm and again at 31 cm. The level at 31 cm contains mm-sized fragments of Fe oxide. X-Ray Fluorescence spectroscopy revealed high Ni/Cr levels concentrated from 9-11 cm and again below 97 cm. We found tektite-like spheroids, dumbbells and teardrops from 8-15 cm depth. They are glasses and they contain appreciable K, consistent with an origin as true tektites but we have not identified the source. Overall, we interpret the high susceptibility, high Ni/Cr and possibly tektite bearing layer as a resulting from the fall of one of the bodies postulated to have fallen with the Peekskill meteorite in 1992. A 1992 age for the top of the Peekskill layer at 8-9 cm depth is consistent with a uniform sedimentation rate in the core and the occurrence of the base of modern Pb at 97 cm depth. From previous work on cores from Central Park Lake, the base of modern Pb represents the year 1880 A.D. We also found other prominent horizons whose ages fit a linear sedimentation rate model. We found a step change in As/Pb ratio whose inferred age matches 1988, the year when Pb and Cu arsenide were banned as pesticides. Our core exhibits peaks in Ca and Sr content and a minor susceptibility peak at 17.5 depth that may represent the 1980 "Great Catskill Toilet Flush" Hudson River flood event. The Catskills contain abundant marine limestone that could serve as a source for Ca and Sr. A prominent susceptibility peak at 37.5 cm could represent a flood in 1955. We also found a peak in Pb at 50 cm depth whose inferred age matches that of the cessation of incinerator burning in 1938. 137Cs and 210Pb ages are in progress and may be available by the time of the meeting. The high Pb and As levels in parts of LWB 4-5 are supported by examination of the coarse fraction. We found two bright orange grains, both with carbon rich coatings. One grain analyses on the X-ray analyzer of an SEM as 8%C, 70% Pb, 17%As and 2% Cu. The second grain analyzes as 10% C, 43% Pb, 1% Ca, 2% P, 27% As, 4% Fe, 2% Ni, 1% Si, and 6% Zn. All analyses are in wt.% on an oxygen free basis. 

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2. Regional and Local Stratigraphic Markers in Three Hudson River Cores Taken Near Peekskill, New York: LWB4-3

   McCann, B.; Abbott, D. H.; Bostick, B. C.; Diallo, M. B.; Abdul, B.; Adeghe, S. (December 2018, American Geophysical Union, Fall Meeting 2018, abstract #B53I-2172)

   We have been studying the stratigraphy of core LWB4-3 taken in 2001 in the Hudson River near Peekskill New York along the transit path of the Peekskill meteorite. We measured magnetic susceptibility at 1 cm intervals down to 108 cm and chemical composition at 1 cm intervals down to 192 cm. The highest magnetic susceptibility occurs at 18 cm depth. This inferred Peekskill meteorite layer with high magnetic susceptibility contains locally higher concentrations of Ni and higher Ni/Cr ratios. Our identification of the high susceptibility, high Ni layer as coming from the fall of the Peekskill meteorite in 1991 is consistent with a uniform sedimentation rate in the core and the occurrence of the base of modern Pb at > 192 cm depth (below the base of the core). From previous work on cores from Central Park Lake, the base of modern Pb represents the year 1880 A.D. We also found other prominent horizons whose ages fit a linear sedimentation rate model. We found a peak in As, whose inferred age matches 1988, the year when Pb and Cu arsenide were banned as pesticides. In addition, we found a modest susceptibility peak above the Peekskill layer whose inferred age matches that of the 1996 Hudson River flood. We found a second modest susceptibility peak below the Peekskill layer whose inferred age matches that of the "Great Catskill Toilet Flush Flood" in 1980. This layer also has local maxima in Pb, Cu and Ca. The Catskills contain Devonian limestone that might be the source of excess Ca. Copper Mine brook is located on the east bank of the Hudson north of Peekskill and is a potential source of Cu during floods. Our core exhibits a distinct increase in Ca content starting at 20 cm depth and increasing towards the top of the core. This prominent increase in Ca may represent 1991 A.D, the time of the invasion of the zebra mussel. We are testing this depth range for calcium carbonate to determine if the upward calcium increase could be from the invasion of the zebra mussel, increased soil erosion or anthropogenic pollution. We found a peak in Pb at 112 cm depth whose inferred age matches that of the cessation of incinerator burning in 1938. Cs-137 and Pb-210 ages are in progress and may be available by the time of the meeting. We also saw an unusual horizon at a depth of 118 cm with a high peak of Cr. This would be approximately the year 1936, which corresponds to a large flood in the Hudson. 

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3. Can We Use Unusual Events to Date Local Sediments and to Develop a Longer Pollution and Volcanic Ash History for the Hudson River?

   Noble, Josephine; Abbott, Dallas (December 2024, American Geophysical Union)

   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. 

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4. Data report: calibration of XRF scanning CaCO3 estimates for the upper 30 m along the Site U1543 splice, International Ocean Discovery Program Expedition 383

   https://doi.org/10.14379/iodp.proc.383.201.2023  

   Kasuya, T.; Iwasaki, S.; Okazaki, Y. (June 2023, Proceedings of the International Ocean Discovery Program Expedition reports)

   To estimate the calcium carbonate (CaCO3) content in the Site U1543 sediment core samples retrieved during International Ocean Discovery Program (IODP) Expedition 383 at high downcore resolution, the X-ray fluorescence (XRF) scanning Ca data, at a spacing of every 10 mm downcore, were calibrated using a total of 118 coulometry-based discrete CaCO3 analyses from the upper 30 meters composite depth (mcd) along the splice. To remove the volume measurement problems of XRF and estimating CaCO3 contents quantitatively, first, raw XRF peak areas were scaled to reduce the effect resulting from the differences in efficiency at absorbing X-rays. Then, the scaled XRF scanning data were normalized to adjust the variability of the amount of XRF peak areas due to porosity and calibrated to properly estimate CaCO3 content. Based on the quality assessment, the calibrated XRF CaCO3 estimates are within ±4.50 wt% of the discrete measurements (1 standard deviation). This data report presents a discrete CaCO3 measurement data set, a normalized median-scaled XRF data set, and XRF CaCO3 estimates on the core depth below seafloor, Method A (CSF-A), and core composite depth below seafloor, Method A (CCSF-A), depth scales. 

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5. Data report: Site U1448 Pleistocene benthic foraminiferal stable isotopes, Andaman Sea, IODP Expedition 353. 10.14379/iodp.proc.353.203.2022

   Clemens, Steven C. (October 2022, Proceedings of the International Ocean Discovery Program Expedition reports)

   This data report presents the benthic foraminiferal oxygen and carbon isotope records for International Ocean Discovery Program Site U1448 in the Andaman Sea. The record includes 1764 analyses spanning from the core top to 203.19 m core composite depth below the seafloor, Method D. This depth interval spans the past 2.755 My with an average temporal resolution of ~1.9 ky (14 cm sample interval). 

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