Wogelius, Roy; Manning, Phillip; DePalma, Robert: Stable isotope data for Sturgeon and Paddlefish specimens, Leaf Mining Data, and Yearling Fish Sizes from the Tanis Location in the Hell Creek Formation of North Dakota (U.S.A.): Isotope Data [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.983836 (dataset in review),

---

In: Wogelius, R et al.: Stable isotope data for Sturgeon and Paddlefish specimens, Leaf Mining Data, and Yearling Fish Sizes from the Tanis Location in the Hell Creek Formation of North Dakota (U.S.A.) [dataset bundled publication]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.983835 (dataset in review)

Fossil specimens were obtained via field work over several years (2014-2021) at the Tanis site, in North Dakota, U.S.A. The specimens include: i) Sub-samples of sturgeon spines and paddlefish dentaries which were epoxy impregnated and sectioned using facilities at Florida Atlantic University. In 2024 a set of these samples were analyzed for stable isotope zonation (carbon and oxygen) at the Department of Earth Sciences, Durham University (UK). A customized micromill setup (computer-controlled ESI/New Wave Micromill with a 500 micron tungsten carbide drill bit) was used to sample fossil sturgeon and paddlefish specimens. Powders were removed by micro-spatula and weighed, with location of drill trace relative to outermost specimen edge logged via high resolution camera imaging. Powders were then analyzed by a Thermo-Finnigan (now Thermo Fisher Scientific) MAT 253 Isotope Ratio Mass Spectrometer into which CO2 was introduced through a Gasbench II device (external precision of about 0.05–0.10‰). Fossil fish powder samples were dissolved in 10 drops of orthophosphoric acid (H3PO4) under a helium (grade 5) atmosphere in exetainer vials. The solution was left to digest at 50 °C for two hours. The resultant gas mixture (CO2 and He) was introduced to a gas chromatographic column to isolate CO2. After passing a second water trap the CO2 was admitted to the mass spectrometer. Each sample run measured isotope ratios in 16 or 17 fossil fish powders and multiple replicates of four reference standards: 1) IAEA (International Atomic Energy Agency) international reference material CO1 (marble), 2) IAEA reference material LS VEC (lithium carbonate), 3) Durham internal standard DCS01 (calcite), and 4) a Durham internal standard DOBINS (equine hydroxyapatite). 13C/12C and 18O/16O ratios are reported as d values (‰ deviations) relative to Vienna PeeDee Belemnite (VPDB). ii) Fossil angiosperm leaves from the time-synchronous Chicxulub Event Deposit, sedimentary units 2a-c, were analyzed for the presence of insect leaf-mining traces, and a tally of trace absent vs. trace present specimens recorded. iii) Fossils of sub-yearling (young-of-year) fish from Unit 2a were also examined. Here. these were identified as members of one of three groups: sturgeon, paddlefish, or Amiidae, and their lengths and orientations recorded. iv) Synchrotron Rapid Scanning-X-ray Fluorescence (SRS-XRF) imaging was performed in this study at wiggler beamline 6-2 (SSRL). Incident beam energy for the experiments was set at 3.15 keV (flux ~10^9 photons-1) for Low-Z mapping and specimens were analysed within a He-purged chamber. Experiments utilized a beam diameter of either 50 or 100 µm, defined by a pinhole. A four-element Vortex ME4 silicon drift detector was used to detect fluoresced X-rays.