[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Polar dinosaur habitats from Cretaceous Arctic Greenhouse World, North Slope, Alaska
A new online paper:
Anthony R. Fiorillo, Paul J. McCarthy & Peter P. Flaig (2015)
A Multi-disciplinary Perspective on Habitat Preferences among
Dinosaurs in a Cretaceous Arctic Greenhouse World, North Slope, Alaska
(Prince Creek Formation: Upper Maastrichtian).
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
Our study offers insight into the habitat preferences for polar dinosaurs.
Alaskan hadrosaur-dominated bonebeds are from wetter lowland delta plain facies.
Alaskan ceratopsian-dominated bonebed from upland coastal plain facies.
Result of adaptation to the seasonality provided by polar terrestrial
In contrast, the tyrannosaurid seems to have had a more ubiquitous distribution.
The Prince Creek Formation of northern Alaska is the most abundant
source of polar dinosaur remains in the world and now corroborating
data from this well-studied rock unit allow for making inferences
about the paleoecological preferences for these extinct polar animals.
The rock unit records high-latitude, alluvial sedimentation and soil
formation on a low gradient, muddy coastal plain. Compound and
cumulative andic Entisols and Inceptisols formed on levees, point
bars, crevasse splays, and along the margins of floodplain lakes,
ponds and swamps. Abundant organic matter, carbonaceous root traces,
Fe-oxide depletion coatings and zoned peds indicate periodic
waterlogging, anoxia and gleying, consistent with a high water table.
In contrast, Fe-oxide mottles, ferruginous and manganiferous
segregations, bioturbation, and less common illuvial clay coatings
indicate recurring oxidation and periodic drying-out of some soils. An
integrated reconstruction of pedogenic processes and biota suggests
that this ancient Arctic coastal plain was influenced by seasonally
fluctuating water table levels and floods, and in distal areas, marine
waters. Four of the five bonebeds in this study are from more distal
areas, represented by lower delta plain facies, while the fifth
bonebed is from a more proximal part of the basin, represented by a
somewhat better drained coastal plain facies.
Bonebeds in the distal areas are dominated by Edmontosaurus sp. while
the more proximal bonebed is dominated by the remains of the
ceratopsian Pachyrhinosaurus perotorum. The distribution of these
bonebeds, sedimentological facies, paleosols and biota, suggest that
Pachyrhinosaurus may have preferred more upland environments while
Edmontosaurus preferred lowland, deltaic environments. This
distribution may be the result of physiological adaptation to the
pronounced seasonality provided by polar terrestrial ecosystems. In
contrast to a preferred habitat distribution of these large
herbivores, the large predatory dinosaur, Nanuqsaurus hoglundi seems
to have had a more ubiquitous distribution across the landscape.