| Title | Palynological insights on Cretaceous clastic basins of southern Yukon, Canada |
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| Author | Bell, K M; Sweet, A R; Haggart, J W; Ryan, J J |
| Source | 52nd Annual Meeting AASP - The Palynological Society, Ghent, Belgium, 2019; 2019 p. 1 |
| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20190081 |
| Meeting | 52nd Annual Meeting AASP-The Palynological Society; Ghent; BE; June 30 - July 5, 2019 |
| Document | book |
| Lang. | English |
| Media | digital |
| Province | Yukon |
| NTS | 95C; 95D; 95E; 105; 106B; 106C; 106D; 115; 116A; 116B; 116C |
| Lat/Long WENS | -141.0000 -124.0000 65.0000 60.0000 |
| Subjects | paleontology; Science and Technology; Nature and Environment; sedimentary basins; palynology; Phanerozoic; Mesozoic; Cretaceous |
| Program | GEM2: Geo-mapping for Energy and Minerals Western Cordillera, Devonian and Permian structural architecture |
| Released | 2019 06 30 |
| Abstract | (unpublished)
Southern Yukon hosts a series of isolated clastic basins of late Early to Late Cretaceous and ?Tertiary ages in the area broadly surrounding the Tintina Trench. The Tintina
Trench is a structural and physiographic feature greater than 1000 km long that spans from northern British Columbia, across Yukon into Yukon Flats, Alaska. During Cretaceous-Tertiary time, the Tintina Fault accommodated an estimated 450 km of
dextral displacement. The discovery of Mesozoic dinosaur tracks in strata within the Tintina Trench (Ross River area) belonging to the Ross River Group that were previously assigned an early Tertiary age has prompted a review of age assignments for
these isolated clastic basins.
Palynological analysis of the dinosaur track-bearing strata of the Ross River area, which we interpret as having been adjacent to the Indian River area during Cretaceous-Tertiary time based on paleogeographic
reconstructions, revealed mid-Cretaceous (Albian to Cenomanian) palynofloral assemblages. Palynofloral assemblages of comparable age (late Albian to Cenomanian) have been identified in this study in both subsurface and outcrop samples from the Indian
River area located to the south of the Tintina Trench, in strata assigned to the informal Indian River formation. The late Albian to Cenomanian assemblages are characterized by spore taxa typical of mid-Cretaceous palynofloras and the presence of
small tricolpate angiosperm pollen coupled with the absence of more advanced angiosperm pollen forms. Outcrop samples collected in the Indian River area have yielded novel late Late Cretaceous (Campanian to Maastrichtian) palynological assemblages
with some assemblages further constrained to an early to mid-Maastrichtian age. The Campanian to Maastrichtian palynofloras include morphologically diverse angiosperm pollen assemblages, including taxa belonging to the triprojectate and oculate
pollen groups. These strata containing Campanian-Maastrichtian assemblages are recognized here as belonging to the informal Sixtymile formation.
The majority of the recovered assemblages from mid- and Late Cretaceous strata in the Indian River
area are indicative of non-marine paleoenvironments, however, mid-Cretaceous assemblages recovered from samples at the base of the McKinnon Creek 137-2 borehole contain abundant dinoflagellate cysts. The documentation of mid-Cretaceous and late Late
Cretaceous aged strata in the Indian River area and the identification of marginal marine paleoenvironments in the Indian River formation has significant stratigraphic, paleoenvironmental, and tectonic implications. |
| Summary | (Plain Language Summary, not published)
The precise age of strata within a series of isolated Cretaceous to Tertiary basins in Southern Yukon is under review. This study identified mid- and
late Late Cretaceous assemblages of fossil pollen, spores and algae in the Indian River area and documented marginal marine paleoenvironments in the Indian River formation, which has significant stratigraphic, paleoenvironmental, and tectonic
implications. |
| GEOSCAN ID | 314715 |
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