@article{straight_barrick_eberth_2004, title={Reflections of surface water, seasonality and climate in stable oxygen isotopes from tyrannosaurid tooth enamel}, volume={206}, ISSN={["0031-0182"]}, DOI={10.1016/j.palaeo.2004.01.006}, abstractNote={Patterns of isotopic variation in enamel of eight Albertosaurus teeth from the Campanian/Maastrichtian Horseshoe Canyon Formation, Alberta, were measured by serial sampling along the growth axis. Cycles in the isotopic values appear to correlate to published tooth growth rates for tyrannosaurids. Tyrannosaurid dinosaur teeth of ~50 mm in length provide ideal repositories of terrestrial climatic information as each records a full annual cycle of body water isotopic variation. The relatively thin enamel precludes problems associated with time-averaging associated with complex growth patterns found in thick mammalian enamel. The most consistent and striking pattern associated with all of the teeth are two relatively closely spaced subequal maxima. These appear to be associated with onset of a seasonal episode of high humidity after the activation of the “amount effect,” where the influence of ambient temperature on surface water (and body water) δ18O ends while temperatures remain above 20 °C. Teeth within a single fossiliferous horizon show the same general isotopic pattern and range. A notable difference in pattern shape and magnitude of isotopic variation between tyrannosaurid teeth from several stratigraphic intervals of the lower Horseshoe Canyon Formation section indicates a climatic changes from strong seasonality (high annual temperature range with distinct precipitation and humidity maxima during each year) at the base of the section to milder seasonality at the top.}, number={3-4}, journal={PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY}, author={Straight, WH and Barrick, RE and Eberth, DA}, year={2004}, month={Apr}, pages={239–256} }
 @article{straight_eberth_2002, title={Testing the utility of vertebrate remains in recognizing patterns in fluvial deposits: An example from the lower Horseshoe Canyon Formation, Alberta}, volume={17}, ISSN={["0883-1351"]}, DOI={10.1669/0883-1351(2002)017<0472:TTUOVR>2.0.CO;2}, abstractNote={Abstract Depositional cycles in fluvial successions are described here as chronostratigraphic packages of strata founded on a laterally extensive, scour-based, amalgamated channel-sand body, overlain by mudrocks, isolated channel fills, avulsion and splay complexes, and paleosols. Ten packages are described from the lower Horseshoe Canyon Formation (Campanian-Maastrichtian), one of a succession of clastic wedges filling the Alberta foreland basin in south-central Alberta. The structure of these packages is consistent with the fall-rise-fall cycle of base-level described in other studies, but the package-bounding scours and internal surfaces are discontinuous and difficult to trace in the mudrock-dominated strata. Terrestrial vertebrate fossils are preserved in relatively fossiliferous, facies-independent horizons 1 to 3 m thick that statistically correlate with the stratigraphic position of package scours and surfaces. Fossiliferous horizons formed as a result of attritional accumulation under an optimum, relatively low, regional deposition rate. Not only do these horizons aid in locating package surfaces, but they also provide insight to the interaction of the package-scale, base-level oscillation with the larger-scale fluctuation in accommodation associated with the formation of the clastic wedge. As such, fossiliferous horizons in the Horseshoe Canyon Formation make better boundary markers than do paleosols, splays, coal seams, or even the surfaces associated with package structure. Therefore, the vertebrate fossil record may supply a means of stratigraphically evaluating sections in other locations in which typical sedimentological and architectural cues for surfaces are absent.}, number={5}, journal={PALAIOS}, author={Straight, WH and Eberth, DA}, year={2002}, month={Oct}, pages={472–490} }