A Paleogene flora from the upper Bonnet Plume Formation of northeast Yukon Territory, Canada

2012 ◽  
Vol 49 (3) ◽  
pp. 547-558 ◽  
Author(s):  
Matthew J. Vavrek ◽  
David C. Evans ◽  
Dennis R. Braman ◽  
Nicolás E. Campione ◽  
Grant D. Zazula
Keyword(s):  
Late Cretaceous ◽  
High Latitude ◽  
Canadian Arctic ◽  
Yukon Territory ◽  
Canadian Arctic Archipelago ◽  
Early Eocene ◽  
Similar Composition ◽  
Plant Macrofossil ◽  
Late Paleocene

Palaeontological exploration of the Bonnet Plume Basin in northwestern Yukon Territory, Canada, has revealed a Late Paleocene to Early Eocene macrofloral assemblage from a channel fill deposit. The flora is typified by cosmopolitan taxa and dominated by deciduous angiosperms, with the notable presence of Zizyphoides , Ettingshausenia , and Corylites . Floras with a similar composition are known from Late Cretaceous through Early Eocene deposits in Alaska and the Canadian Arctic Archipelago, where they have been interpreted as evidence for warm, equable temperatures. This collection represents the most diverse known Paleogene plant macrofossil assemblage from the Yukon Territory and helps to expand our knowledge of ancient high-latitude floras.

scholarly journals Palaeoenvironmental Interpretation of Late Quaternary Marine Molluscan Assemblages, Canadian Arctic Archipelago

2002 ◽  
Vol 54 (3) ◽  
pp. 301-315 ◽  
Author(s):  
Sandra Gordillo ◽  
Alec E. Aitken
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Continental Shelf ◽  
Marine Sediments ◽  
High Latitude ◽  
Late Quaternary ◽  
Canadian Arctic ◽  
High Arctic ◽  
Canadian Arctic Archipelago ◽  
Preservation Potential

Abstract This study examines neonto- logical and palaeontological data pertaining to arctic marine molluscs with the goal of reconstructing the palaeoecology of Late Quaternary ca. 12-1 ka BP glaciomarine environments in the Canadian Arctic Archipelago. A total of 26 taxa that represent 15 bivalves and 11 gastropods were recorded in shell collections recovered from Prince of Wales, Somerset, Devon, Axel Heiberg and Ellesmere islands. In spite of taphonomic bias, the observed fossil faunas bear strong similarities to modern benthic molluscan faunas inhabiting high latitude continental shelf environments, reflecting the high preservation potential of molluscan taxa in Quaternary marine sediments. The dominance of an arctic-boreal fauna represented by Hiatella arctica, Mya truncata and Astarte borealis is the product of natural ecological conditions in high arctic glaciomarine environments. Environmental factors controlling the distribution and species composition of the Late Quaternary molluscan assemblages from this region are discussed.

A Canadian Arctic Fjord with Some Comparisons to Fjords of the Western Americas

1976 ◽  
Vol 33 (10) ◽  
pp. 2272-2285 ◽  
Author(s):  
R. A. Lake ◽  
E. R. Walker
Keyword(s):  
South America ◽  
Sea Ice ◽  
High Latitude ◽  
Canadian Arctic ◽  
Water Structure ◽  
Canadian Arctic Archipelago ◽  
Energy Inputs ◽  
Arctic Fjord ◽  
North And South America ◽  
North And South

Aspects of oceanography of d’Iberville Fiord (80°30′N, 80°00′W) are compared to oceanography of west Coast fjords of North and South America. Because of high latitude, hence, cold temperature, d’Iberville Fiord is covered by sea ice for at least 11 mo of each year. An estuarine circulation flows under sea ice except for those Augusts in which sea ice clears. The sea-ice cover and the small tides typical of the northwest Canadian arctic archipelago mean energy inputs to fjord waters are small and currents light. However, water structure in many respects is not dissimilar to that in fjords elsewhere. Effects of a large active glacier debouching into headwaters of d’Iberville Fiord are noted.

Zingiberopsis, a fossil genus of the ginger family from Late Cretaceous to early Eocene sediments of Western Interior North America

1978 ◽  
Vol 56 (9) ◽  
pp. 1136-1152 ◽  
Author(s):  
Leo J. Hickey ◽  
Rayma Kempinsky Peterson
Keyword(s):  
New Species ◽  
North America ◽  
Late Cretaceous ◽  
New Combination ◽  
Early Eocene ◽  
Clear Trend ◽  
Late Paleocene ◽  
Fossil Genus ◽  
A New Species

Zingiberopsis attenuata Hickey and Peterson is a new species of monocotyledon from the Paleocene Paskapoo Formation of Alberta. Leaves of this species with their parallel veins grouped into three size sets are intermediate between the Late Cretaceous Zingiberopsis magnifolia (Knowlton) Hickey, new combination, with four discrete sets and Zingiberopsis isonervosa Hickey, of late Paleocene and early Eocene age, with only one set. Zingiberopsis has large, elliptic to ovate leaves with a costa composed of a number of concurrent strands, a set of parallel veins emerging at low angles from the costa, and relatively distantly spaced transverse veins running between adjacent parallel veins. Morphology of the genus matches that of Alpinia in the Zingiberaceae except for greater irregularity of the parallel vein set at and near their origin on the costa and the lack of any evidence of a ligule on the petiole as in Alpinia. Species of Zingiberopsis demonstrate a clear trend toward loss of the wider parallel vein subsets over the approximately 20-million-year range of the genus. In addition, the overlooked character of the arrangement of the parallel vein subsets across the width of the leaf may have potential in the taxonomic determination of monocotyledonous leaves.

A Late Cretaceous (Turonian–Coniacian) high-latitude turtle assemblage from the Canadian Arctic

2005 ◽  
Vol 42 (12) ◽  
pp. 2073-2080 ◽  
Author(s):  
Donald B Brinkman ◽  
John A Tarduno
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
High Latitude ◽  
Canadian Arctic ◽  
High Latitudes ◽  
Axel Heiberg Island ◽  
Vertebrate Assemblage

Three turtles are present in a Turonian–Coniacian age high-latitude vertebrate assemblage from Axel Heiberg Island: Borealochelys axelheibergensis gen. et sp. nov., a generically indeterminate eucryptodire, and a trionychid. The assemblage differs from most Late Cretaceous turtle assemblages from North America in that members of the Paracryptodira are absent. The absence of this group is interpreted as a result of latitudinal differentiation of turtle assemblages in North America during the Late Cretaceous. The level of diversity of turtles in the Axel Heiberg assemblage is comparable to that of mid-latitude assemblages associated with a mean annual paleotemperature of 14 °C, adding to the evidence for high mean annual temperatures at high latitudes during Turonian–Coniacian times.

scholarly journals Southern high-latitude terrestrial climate change during the Paleocene–Eocene derived from a marine pollen record (ODP Site 1172, East Tasman Plateau)

2014 ◽  
Vol 10 (1) ◽  
pp. 291-340 ◽  
Author(s):  
L. Contreras ◽  
J. Pross ◽  
P. K. Bijl ◽  
R. B. O'Hara ◽  
J. I. Raine ◽  
...  
Keyword(s):  
High Latitude ◽  
Vegetation Dynamics ◽  
Temperate Forests ◽  
Global Climate ◽  
Pollen Record ◽  
Early Eocene ◽  
Precipitation Regime ◽  
Late Paleocene ◽  
Cool Temperate ◽  
Early Paleogene

Abstract. Reconstructing the early Paleogene climate dynamics of terrestrial settings in the high southern latitudes is important to assess the role of high-latitude physical and biogeochemical processes in the global climate system. However, whereas a number of high-quality Paleogene climate records has become available for the marine realm of the high southern latitudes over the recent past, the long-term evolution of coeval terrestrial climates and ecosystems is yet poorly known. We here explore the climate and vegetation dynamics on Tasmania from the middle Paleocene to the early Eocene (60.7–54.2 Ma) based on a sporomorph record from Ocean Drilling Program (ODP) Site 1172 on the East Tasman Plateau. Our results show that three distinctly different vegetation types thrived on Tasmania under a high-precipitation regime during the middle Paleocene to early Eocene, with each type representing different temperature conditions: (i) warm-temperate forests dominated by gymnosperms that were dominant during the middle and late Paleocene; (ii) cool-temperate forests dominated by southern beech (Nothofagus) and araucarians across the middle/late Paleocene transition interval (~59.5 to ~59.0 Ma); and (iii) paratropical forests rich in ferns that were established during and in the wake of the Paleocene–Eocene Thermal Maximum (PETM). The transient establishment of cool-temperate forests lacking any frost-sensitive elements (i.e., palms and cycads) across the middle/late Paleocene transition interval indicates markedly cooler conditions, with the occurrence of frosts in winter, on Tasmania during that time. The integration of our sporomorph data with previously published TEX86-based sea-surface temperatures from ODP Site 1172 documents that the vegetation dynamics on Tasmania were closely linked with the temperature evolution in the Tasman sector of the Southwest Pacific region. Moreover, the comparison of our season-specific climate estimates for the sporomorph assemblages from ODP Site 1172 with the TEX86L- and TEX86H-based temperature data suggests a warm-season bias of both calibrations for the early Paleogene of the high southern latitudes.

Vertebrate fossils (Dinosauria) from the Bonnet Plume Formation, Yukon Territory, Canada

2012 ◽  
Vol 49 (2) ◽  
pp. 396-411 ◽  
Author(s):  
David C. Evans ◽  
Matthew J. Vavrek ◽  
Dennis R. Braman ◽  
Nicolás E. Campione ◽  
T. Alexander Dececchi ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Polar Region ◽  
Canadian Arctic ◽  
Yukon Territory ◽  
Field Surveys ◽  
Considerable Potential ◽  
Terrestrial Vertebrates ◽  
New Material ◽  
Diverse Community

Dinosaurs and other terrestrial vertebrates are poorly documented in the Mesozoic of the Canadian polar region. Here, we provide a complete review of the Upper Cretaceous (Maastrichtian) vertebrate fauna of the Bonnet Plume Formation in the northeastern Yukon Territory, Canada, which includes the description of the first newly collected dinosaur bones from this unit in almost half a century. Previously reported fragmentary dinosaur remains collected in the early 1960’s pertain to an indeterminate hadrosaurid. New material includes a poorly preserved forelimb bone and a pedal phalanx. These new remains pertain to at least one species of non-hadrosaurid ornithischian dinosaur, and the humerus is tentatively referred to a small-bodied basal ornithopod. The new vertebrate fossils from the Bonnet Plume Formation provide further evidence of vertebrates from this unit. However, directed field surveys in 2008 and 2009 suggest that vertebrate fossils are not abundant. A review of the known localities of terrestrial Mesozoic vertebrates from the Canadian Arctic indicate that it had a relatively diverse community of terrestrial vertebrates, including dinosaurs, during the Late Cretaceous, but emphasizes our limited knowledge of the Mesozoic Arctic and considerable potential for future exploration and discovery.

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