Sedimentary strata of the Neoproterozoic Mackenzie Mountains Supergroup (MMSG) and Windermere Supergroup (WSG) occupy the cores of anticlines in the Mackenzie Mountains of the Canadian Cordilleran Foreland Belt. Stratigraphic and structural evidence suggest that these rocks have undergone several episodes of burial and unroofing relatively intact. We report single‐grain detrital muscovite 40Ar/39Ar and zircon (U‐Th)/He (ZHe) data from a suite of samples across the fold‐thrust belt and the Neoproterozoic stratigraphic record. The strata have not reached high enough temperatures to reset the muscovite 40Ar/39Ar system, and instead our detrital muscovite data refine Tonian‐Cryogenian depositional ages. Single‐crystal ZHe dates range from 432 ± 35 to 46 ± 4 Ma, indicating that MMSG and WSG strata have not been heated sufficiently to fully reset the ZHe system. These factors make the Neoproterozoic strata an attractive natural laboratory to test the utility of the zircon radiation damage and annealing model on the quantification of thermal histories from detrital zircon populations that have accumulated radiation damage over long geologic timescales. Thermal modeling reveals that (1) a substantial sedimentary package was deposited following the Devonian and removed during Permo‐Triassic cooling, and (2) the Cordilleran deformation front propagated through the study area from the Albian to the Paleocene, with a moderate increase in cooling rates between 75–67 Ma in the southwest and 60–55 Ma at the deformation front. Ultimately, relationships between radiation damage and helium diffusion kinetics in zircon explain substantial ZHe date dispersion and elucidate the temperature‐time history of the northern Canadian Cordillera.

Detrital zircon studies are providing new insights on the evolution of sedimentary basins but the role of sedimentary recycling remains largely undefined. In a broad region of northwestern North America, this contribution traces the pathway of detrital zircon sand grains from Proterozoic sandstones through Phanerozoic strata and argues for multi-stage sedimentary recycling over more than a billion years. As a test of our hypothesis, integrated palynology and detrital zircon provenance provides clear evidence for erosion of Carboniferous strata in the northern Cordillera as a sediment source for Upper Cretaceous strata. Our results help to calibrate Earth's sedimentary cycle by showing that recycling dominates sedimentary provenance for the refractory mineral zircon.

In western Canada samples obtained from outcrops of the Lower Triassic Toad and Grayling formations and core samples from coeval subsurface sections of the Montney Formation contain well-preserved palynofloras. These are generally dominated by taeniate bisaccate (e.g. Lunatisporites noviaulensis) and polyplicate gymnosperm pollen (e.g. Ephedripites steevesiae). Acanthomorph acritarchs (e.g. Filisphaeridium sp. cf. F. deunffii, Micrhystridium breve, M. setasessitante, Wilsonastrum colonicum) are often common to abundant. In addition, the stratigraphically and environmentally significant alga(?) Chordecystia chalasta occurs. These western Canadian Lower Triassic assemblages correlate with the Griesbachian Chordecystia chalasta-Striatoabieites richteri Assemblage Zone of the Sverdrup Basin, Canadian Arctic Archipelago, Nunavut.The environment of deposition, based on the abundance of pollen and spores and common occurrence of acanthomorph acritarchs, is near-shore marine. At a few horizons in the Montney Formation acritarchs are dominant, and this may indicate deeper water facies. Trace fossils in core and outcrop, lithofacies and sedimentary structures indicate fully marine, proximal offshore to lower and upper shoreface settings. The paleoclimate at the site of plant growth, based on the dominance of taeniate bisaccate pollen and polyplicate pollen, was probably arid.The Lower Triassic samples commonly include reworked Middle and Upper Devonian spores and less common Lower Carboniferous spores, demonstrating that significant erosion of Paleozoic rocks took place in early Triassic time in this area; recognition of such erosional events is relevant to sequence stratigraphic reconstructions.The thermal maturity of the in situ organic matter in the study areas is generally low (close to the threshold or within the "oil window"). This, along with the abundant amorphous and common exinous material, suggests a potential for the generation of liquid hydrocarbons. At one locality in southeast Yukon within the deformation belt the thermal maturity is high, suggesting some potential for dry gas generation. Reworked material generally has a slightly higher maturity, a fact that should be taken into consideration when assessing other thermal maturity indicators such as vitrinite reflectance. RÉSUMÉDans l'ouest du Canada, des échantillons provenant des affleurements des formations du Grayling d'âge du Triasique inférieur, ainsi que des échantillons de carottes provenant de sections contemporaines du sous-sol de la Formation de Montney, contiennent des palynoflores en bon état de conservation. Ils sont généralement dominés par des taénites bisaques (ex. Lunatisporites noviaulensis) et des pollens de polyplicates gymnospermes (ex. Ephedripites steevesiae). Des acritarches acanthomorphes (ex. Filisphaeridium sp. cf. F. deunffii, Micrhystridium breve, M. setasessitante, Wilsonastrum

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