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TitleEarly Cretaceous vegetation and climate change at high latitude: palynological evidence from Isachsen Formation, Arctic Canada
AuthorGalloway, J M; Tullius, D N; Evenchick, C A; Swindles, G T; Hadlari, T; Embry, A
SourceCretaceous Research vol. 56, 2015 p. 399-420,
Alt SeriesEarth Sciences Sector, Contribution Series 20140260
Mediapaper; on-line; digital
File formatpdf
NTS27; 37; 47; 57; 67; 77; 87; 28; 38; 48; 58; 68; 78; 88; 98; 19; 29; 39; 49; 59; 69; 79; 89; 99; 120; 340; 560
AreaSverdrup Basin; Canadian Arctic
Lat/Long WENS-128.0000 -56.0000 84.0000 68.0000
Subjectsenvironmental geology; paleontology; vegetation; climate, arctic; climate; climate effects; palynology; palynological analyses; palynostratigraphy; Isachsen Formation; Sverdrup Basin; climate change; Mesozoic; Cretaceous
Illustrationslocation maps; profiles; tables; stratigraphic columns; photomicrographs
ProgramWestern Arctic Sverdrup Basin, GEM2: Geo-mapping for Energy and Minerals
AbstractQuantitative palynology of the marginal marine and deltaic-fluvial Isachsen Formation of the Sverdrup Basin, Canadian Arctic, provides insight into high latitude climate during much of the Early Cretaceous (Valanginian to early Aptian). Detrended Correspondence Analysis of main pollen and spore taxa is used to derive three ecological groupings influenced by moisture and disturbance based on the botanical affinities of palynomorphs: 1) a mixed coniferous assemblage containing both lowland and upland components; 2) a conifer-filicopsid community that likely grew in dynamic lowland habitats; and, 3) a mature dry lowland community composed of Cheirolepidiaceans. Stratigraphic changes in the relative abundance of pollen and spore taxa reflect climate variability in this polar region during the ~20 Mya history of the Isachsen Formation. The late Valanginian was relatively cool and moist and promoted lowland conifer-filicopsid communities. Warming in the Hauterivian resulted in the expansion coniferous communities in well-drained or arid hinterlands. A return to relatively cool and moist conditions in the Barremian resulted in the expansion of mixed lowland communities. This work demonstrates the utility of a multivariate statistical approach to palynology to provide insight into the composition and dynamics of ecosystems and climate of high latitude regions during the Early Cretaceous.
Summary(Plain Language Summary, not published)
This paper uses pollen and spores preserved in the Early Cretaceous Isachsen Formation exposed in the central Sverdrup Basin to reconstruct regional paleoclimate. We find that climate was relatively cool and moist and supported early to mid-successional communities in lowland habitats. Warming approximately 134 million years ago promoted expansion of late successional coniferous communities in well-drained or arid hinterland. Approximately 131 million years ago, relatively cool and moist conditions returned and promoted early mid-successional mixed lowland communities.