| Title | Lower Triassic river-dominated deltaic successions from the Sverdrup Basin, Canadian Arctic |
| |
| Author | Midwinter, D; Hadlari, T ; Dewing, K |
| Source | Palaeogeography, Palaeoclimatology, Palaeoecology vol. 476, 2017 p. 55-67, https://doi.org/10.1016/j.palaeo.2017.03.017 |
| Image |  |
| Year | 2017 |
| Alt Series | Earth Sciences Sector, Contribution Series 20160435 |
| Publisher | Elsevier BV |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Northwest Territories; Nunavut |
| NTS | 120; 28; 29; 340; 38; 39; 48; 49; 540; 58; 59; 68; 69; 78; 79; 88; 89; 98; 99 |
| Lat/Long WENS | -128.0000 -64.0000 84.0000 72.0000 |
| Subjects | sedimentology; stratigraphy; Nature and Environment; deltas; deltaic deposits; braided channels; basins; depositional environment; vegetation; sandstones; sedimentation rates; Plants |
| Illustrations | location maps; stratigraphic columns; tables; photographs; photomicrographs; ternary diagrams |
| Program | GEM2: Geo-mapping for Energy and Minerals Western Arctic Sverdrup Basin |
| Released | 2017 03 31 |
| Abstract | Sedimentary facies analysis of Lower Triassic deltaic deposits tests a hypothesis that the Latest Permian Mass Extinction influenced sedimentation in the Sverdrup Basin. The pre-existing stratigraphic
framework sub-divides the coeval Blind Fiord and Bjorne formations into three T-R sequences and component braid-deltaic successions, with the Latest Permian Mass Extinction at the base of the first. As described here, river-dominated deltaic facies
of the first sequence are indicative of high-magnitude flood flows resulting in a predominance of upper flow regime sedimentary structures. River-dominated deltaic facies of the second sequence contain fewer upper flow regime structures recording
lower energy flows that generated mostly 3D and 2D dunes. The third sequence marks the furthest progradation of the braid-delta into the basin.
Beyond the gross braided stream characteristics of the three river-dominated deltaic successions,
the lower two provide a compelling comparison of depositional environments because they formed in the same basin within only a few millions years and thereby were probably subject to similar boundary conditions. We propose that the lower, Induan,
sequence is dominated by upper-flow regime plane beds due to the effect of the Latest Permian Mass Extinction on vegetative cover, whereas the middle sequence is dominated by dune-scale cross-stratification formed by lower magnitude, less flood-type
flows during the Olenekian. |
| Summary | (Plain Language Summary, not published)
We studied delta deposits that had formed shortly after one of Earth's greatest mass extinctions at the Permo-Triassic boundary. We found that the
sedimentary signature was much like landscapes before the evolution of land plants, and concluded that the mass extinction probably affected vegetation. |
| GEOSCAN ID | 299875 |
|
|