Cenozoic Exhumation History of the Eastern Margin of the Northern Canadian Cordillera

McKay, Ryan; Enkelmann, Eva; Hadlari, Thomas; Matthews, W. A.; Mouthereau, Frédéric

doi:10.1029/2020tc006582

Cited by 11 publications

(9 citation statements)

References 71 publications

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“…Evaluating the data for a fully reset detrital sample follows the recommendations for evaluating a bedrock thermochronologic data as outlined above (section 3.1). In reality, many reset sedimentary rocks show significant dispersion, such that calculating and reporting mean sample dates may be inappropriate (e.g., McKay et al, 2021), owing to a combination of the reasons described at the beginning of this section as well as possible effects of variable damage annealing during burial. This dispersion appears to be particularly common for pre-Cenozoic sedimentary strata because kinetic effects are amplified over long timescales (section 2.6; Fig.…”

Section: Additional Considerations For Detrital Studiesmentioning

confidence: 99%

“…5B). Forward tTpath modeling can be a useful tool for exploring the possible range of (U-Th)/He date dispersion due to varying kinetic parameters (e.g., eU, grain size) and pre-depositional thermal histories (for samples with incomplete damage annealing during burial) (e.g., Flowers et al, 2007;Powell et al, 2016;Schwartz et al, 2017;Fox et al, 2019;McKay et al, 2021).…”

Section: Additional Considerations For Detrital Studiesmentioning

confidence: 99%

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(U-Th)/He chronology: Part 2. Considerations for evaluating, integrating, and interpreting conventional individual aliquot data

et al. 2022

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The (U-Th)/He dating technique is an essential tool in Earth science research with diverse thermochronologic, geochronologic, and detrital applications. It is now used in a wide range of tectonic, structural, petrological, sedimentary, geomorphic, volcanological, and planetary studies. While in some circumstances the interpretation of (U-Th)/He data is relatively straightforward, in other cases it is less so. In some geologic contexts, individual analyses of the same mineral from a single sample are expected to yield dates that differ well beyond their analytical uncertainty owing to variable He diffusion kinetics. Although much potential exists to exploit this phenomenon to decipher more detailed thermal history information, distinguishing interpretable intra-sample data variation caused by kinetic differences between crystals from uninterpretable overdispersion caused by other factors can be challenging. Nor is it always simple to determine under what circumstances it is appropriate to integrate multiple individual analyses using a summary statistic such as a mean sample date or to decide on the best approach for incorporating data into the interpretive process of thermal history modeling. Here we offer some suggestions for evaluating data, attempt to summarize the current state of thinking on the statistical characterization of data sets, and describe the practical choices (e.g., model structure, path complexity, data input, weighting of different geologic and chronologic information) that must be made when setting up thermal history models. We emphasize that there are no hard and fast rules in any of these realms, which continue to be an important focus of improvement and community discussion, and no single interpretational and modeling philosophy should be forced on data sets. The guiding principle behind all suggestions made here is for transparency in reporting the steps and assumptions associated with evaluating, integrating, and interpreting data, which will promote the continued development of (U-Th)/He chronology.

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Section: Additional Considerations For Detrital Studiesmentioning

confidence: 99%

Section: Additional Considerations For Detrital Studiesmentioning

confidence: 99%

(U-Th)/He chronology: Part 2. Considerations for evaluating, integrating, and interpreting conventional individual aliquot data

et al. 2022

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“…A third phase of uplift is inferred around 33–20 Ma (Enkelmann et al., 2019), which would make the current NE‐SW shortening the fourth period of deformation since the mountains formed. These uplift phases have been linked to North America plate movement (Enkelmann et al., 2019; McKay et al., 2021) but there is yet no thermochronological evidence of recent uplift and erosion (Enkelmann et al., 2019). This may indicate that the current episode has not created enough uplift to produce a thermal signature, or that sample availability excludes areas of recent active uplift.…”

Section: Introductionmentioning

confidence: 99%

Lithospheric S Wave Velocity Variations Beneath the Mackenzie Mountains and Northern Canadian Cordillera

et al. 2022

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The Mackenzie Mountains (MMs) in the Yukon and Northwest Territories, Canada, are an enigmatic mountain range. They are currently uplifting (Leonard et al., 2008, http://https//doi.org/10.1029/2007JB005456), yet are about 700 km from the nearest plate boundary. Their arcuate shape is distinct and extends over 100 km eastward from the general trend of the Northern Canadian Cordillera. To better assess the cause and conditions of the current uplift, we processed ambient seismic noise data from a linear array of broadband seismographs crossing the mountains, along with other regional seismic stations, to estimate Rayleigh wave phase velocities between 6 and 40 s periods. From this, we estimated phase velocity dispersion and performed a tomographic inversion to estimate VS. Tomography reveals a low‐velocity structure that extends upward from the base of the ∼50–66 km thick lithosphere to the upper crust, and we hypothesize that inferred low density and low rigidity associated with the VS anomaly localizes the ongoing uplift and thrust‐dominated seismicity of the MMs. Additionally, we find relatively low crustal velocities that extend to the west of the MMs, suggesting that strain transfer from the Gulf of Alaska plate boundary plays a driving role as the crust translates to the northeast and buckles up against the craton consistent with the orogenic float hypothesis of Mazzotti and Hyndman (2002, http://https//doi.org/10.1130/0091-7613(2002)030%3C0495:YCASTA%3E2.0.CO;2). Finally, we observe lithospheric azimuthal anisotropy with an NW‐SE fast direction. This is nearly orthogonal to teleseismic shear wave splitting measurements in the central MMs, and suggests that asthenosphere flow and lithospheric strain are not aligned in this region.

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“…For 25 samples we found 2-7 inclusion-free, unbroken, and crack-free apatite grains that were selected for AHe analysis. All (U-Th-Sm)/He analysis was conducted in the Geo-and Thermochronology laboratory of the University of Calgary and followed our standard procedures that are described in detail by McKay et al (2021). Fission track analysis was also carried out on 23 samples (Table 3) at the Geo-and Thermochronology laboratory of the University of Calgary.…”

Section: Methodsmentioning

confidence: 99%

Resolving the Cenozoic History of Rock Exhumation Along the Central Rocky Mountain Trench Using Apatite Low‐Temperature Thermochronology

et al. 2021

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The Canadian Cordillera comprises major mountain belts that dominate Western Canada and was formed following the accretion of multiple terranes and island arcs. The Rocky Mountain Trench (RMT) is a ∼1,600 km long valley that extends through the Canadian Cordillera from northwest Montana to the Yukon and acts as the boundary between the Cordillera's foreland (Rocky Mountains) and the metamorphic hinterland and accreted terranes (Figure 1). At its northernmost point, the RMT aligns with the Tintina Fault and extends through Yukon and into Alaska (Figure 1). The formation of this continuous geomorphic feature has been a topic for debate since its description by Daly (1912) (e.g., Leech, 1966McMechan, 2000), however, our understanding of this continental scale feature remains limited.Many argue that the RMT is located above a continental scale weakness in the crust, that possibly formed during Proterozoic rifting of Rodinia, and has allowed for the formation of such a continuous fault system

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Cenozoic Exhumation History of the Eastern Margin of the Northern Canadian Cordillera

Cited by 11 publications

References 71 publications

(U-Th)/He chronology: Part 2. Considerations for evaluating, integrating, and interpreting conventional individual aliquot data

(U-Th)/He chronology: Part 2. Considerations for evaluating, integrating, and interpreting conventional individual aliquot data

Lithospheric S Wave Velocity Variations Beneath the Mackenzie Mountains and Northern Canadian Cordillera

Resolving the Cenozoic History of Rock Exhumation Along the Central Rocky Mountain Trench Using Apatite Low‐Temperature Thermochronology

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