Use of multiple oxygen isotope proxies for elucidating Arctic Cretaceous palaeo-hydrology

Abstract

Stable oxygen isotope analysis of siderite and dinosaur tooth enamel phosphate from the Campanian–Maastrichtian Prince Creek Formation, Alaska, USA, are analysed to determine the palaeohydrology of the ancient Colville Basin north of the Ancestral Brooks Range. δ18O of freshwater siderites relative to V-PDB ranges between −14.86 and −16.21‰. Dinosaur tooth enamel δ18O from three different sites (Kikak–Tegoseak, Pediomys Point, Liscomb) range between +3.9‰ and +10.2.0‰. δ18Ometeoric water are calculated from δ18Osiderite that formed at seasonal temperatures ranging from −2 to 14.5 °C, with a mean annual temperature of 6.3 °C. At 6.3 °C, the δ18Ow calculated from siderite ranged between −22.23 and −20.89‰ V-SMOW. Ingested water compositions are estimated from dinosaur teeth assuming body temperatures of 37 °C and local relative humidity of 77.5%, resulting in values ranging from −28.7 to −20.4‰ V-SMOW, suggesting consumption of meteoric water and orographically depleted runoff from the Brooks Range. The ranges in calculated δ18Ometeoric water are compatible between the two proxies, and are mutually corroborating evidence of extremely 18O-depleted precipitation at high latitudes during the Late Cretaceous relative to those generated using general circulation models. This depletion is proposed to result from increased rainout effects from an intensified hydrological cycle, which probably played a role in sustaining polar warmth.Supplementary material:Parameters used for generation of equations compared to Kohn (1996) can be found at http://www.geolsoc.org.uk/SUP18642

A multi-disciplinary perspective on habitat preferences among dinosaurs in a Cretaceous Arctic greenhouse world, North Slope, Alaska (Prince Creek Formation: lower Maastrichtian)

“…And secondly, the preferred habitat selection for hadrosaurs and ceratopsians in this more northern region, based on the relationship of the faunal composition within bonebeds to sedimentary environments supports the ecological model put forth based on stable isotopes (Suarez et al, 2013). This pattern is the reverse of the pattern found to the south.…”

“…Maastrichtian age for the mass accumulation of horned-dinosaur bones recovered from the quarry there (Fiorillo et al, 2010a, b), consistent with more recent palynological and radiometric evidence for a similar age in the Liscomb bonebed area (Flaig, 2010;Flaig et al, 2013Flaig et al, , 2014 (Witte et al, 1987;Besse and Courtillot, 1991;Lawver et al, 2002), placing the bonebeds above the Arctic Circle at the time of deposition.…”

“…These dinosaur skeletal remains are found in bonebeds in a variety of alluvial environments in the Prince Creek Formation (Fiorillo et al, 2010a, b;Flaig et al, 2011Flaig et al, , 2013Flaig et al, 2014). Bonebeds are notable occurrences in the fossil record as they potentially record a wealth of paleobiological information (see Rogers et al, 2007 for overview) and are one of the most important sources of information in understanding ancient ecosystems.…”

“…Despite the known lateral topographic complexity of floodplain sub-environments, and the corresponding effects on water table levels and drainage conditions (Wright, 1992;McCarthy and Plint, 2003), a general up-dip improvement in drainage conditions can still be documented for the Prince Creek Formation (Brandlen, 2008;Flaig et al, 2011Flaig et al, , 2013. By integrating data on the distribution of bonebeds with paleopedological and biotic data and sedimentary facies from both more proximal and distal settings we provide insights into Arctic dinosaur habitat preferences for the predatory dinosaur guild and corroborate a previous model proposed for preferred habitat selection among the large herbivore guild.…”

“…Mull et al (2003) (Brouwers et al, 1987;Waller and Marincovich, 1992). Phillips (1990; and Conrad et al (1990) were the first to attempt to construct a detailed stratigraphic and chronometric framework that included the highly fossiliferous terrestrial interval assigned (Brandlen, 2008;Fiorillo et al, 2010 a, b;Flaig, 2010;Flaig et al, 2011Flaig et al, , 2013.…”