Decadal 10Be, 26Al and 36Cl QA measurements on the SUERC 5 MV accelerator mass spectrometer

Xu, Sheng; Freeman, Stewart P.H.T.; Rood, Dylan H.; Shanks, Richard

doi:10.1016/j.nimb.2015.03.064

Cited by 30 publications

(16 citation statements)

References 15 publications

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“…All samples were prepared at the University of Vermont Cosmogenic Isotope Laboratory facilities following standard lab protocols [e.g., Corbett et al ., ]. Sample 26 Al/ 27 Al and 10 Be/ 9 Be ratios were measured on the Scottish Universities Environmental Research Centre accelerator mass spectrometry (AMS) laboratory in East Kilbride, Scotland [ Xu et al ., ]. The supporting information provides a detailed description of sample preparation, AMS measurement, and blank correction protocols.…”

Section: Methodsmentioning

confidence: 99%

Differential uplift and incision of the Yakima River terraces, central Washington State

et al. 2016

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The fault‐related Yakima folds deform Miocene basalts and younger deposits of the Columbia Plateau in central Washington State. Geodesy implies ~2 mm/yr of NNE directed shortening across the folds, but until now the distribution and rates of Quaternary deformation among individual structures has been unclear. South of Ellensburg, Washington, the Yakima River cuts a ~600 m deep canyon across several Yakima folds, preserving gravel‐mantled strath terraces that record progressive bedrock incision and related rock uplift. Here we integrate cosmogenic isochron burial dating of the strath terrace gravels with lidar analysis and field mapping to quantify rates of Quaternary differential incision and rock uplift across two folds transected by the Yakima River: Manastash and Umtanum Ridge. Isochron burial ages from in situ produced 26Al and 10Be at seven sites across the folds date episodes of strath terrace formation over the past ~2.9 Ma. Average bedrock incision rates across the Manastash (~88 m/Myr) and Umtanum Ridge (~46 m/Myr) anticlines are roughly 4 to 8 times higher than rates in the intervening syncline (~14 m/Myr) and outside the canyon (~10 m/Myr). These contrasting rates demonstrate differential bedrock incision driven by ongoing Quaternary rock uplift across the folds at rates corresponding to ~0.13 and ~0.06 mm/yr shortening across postulated master faults dipping 30 ± 10°S beneath the Manastash and Umtanum Ridge anticlines, respectively. The reported Quaternary shortening across the anticlines accounts for ~10% of the ~2 mm/yr geodetic budget, suggesting that other Yakima structures actively accommodate the remaining contemporary deformation.

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Section: Methodsmentioning

confidence: 99%

Differential uplift and incision of the Yakima River terraces, central Washington State

et al. 2016

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“…Samples CS‐11, CS‐12, and CS‐17 and replicates of samples CS‐14, CS‐24, and CS‐30 were processed at the Scottish Universities Environmental Research Centre (SUERC) (http://www.gla.ac.uk/suerc/index.html) in East Kilbride, Scotland following procedures based on methods modified from Kohl and Nishiizumi () and Child et al (), at the GU‐SUERC Cosmogenic Isotope Laboratory. The 10 Be isolated in Scotland was measured at the SUERC Accelerator Mass Spectrometry Laboratory (Xu et al , ). Blank correction was done on the basis of one blank processed with these samples.…”

Section: Methodsmentioning

confidence: 99%

Rates of erosion and landscape change along the Blue Ridge escarpment, southern Appalachian Mountains, estimated from in situ cosmogenic ¹⁰Be

Linari

Bierman

Portenga

et al. 2016

Earth Surf Processes Landf

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The Blue Ridge escarpment, located within the southern Appalachian Mountains of Virginia and North Carolina, forms a distinct, steep boundary between the lower‐elevation Piedmont and higher‐elevation Blue Ridge physiographic provinces. To understand better the rate at which this landform and the adjacent landscape are changing, we measured cosmogenic beryllium‐10 (10Be) in quartz separated from sediment samples (n = 50) collected in 32 streams and from three exposed bedrock outcrops along four transects normal to the escarpment, allowing us to calculate erosion rates integrated over 104–105 years. These basin‐averaged erosion rates (5.4–49 m Myr−1) are consistent with those measured elsewhere in the southern Appalachain Mountains and show a positive relationship between erosion rate and average basin slope. Erosion rates show no relationship with basin size or relative position of the Brevard fault zone, a fundamental structural element of the region. The cosmogenic isotopic data, when considered along with the distribution of average basin slopes in each physiographic province, suggest that the escarpment is eroding on average more rapidly than the Blue Ridge uplands, which are eroding more rapidly than the Piedmont lowlands. This difference in erosion rates by geomorphic setting suggests that the elevation difference between the uplands and lowlands adjacent to the escarpment is being reduced but at extremely slow rates. Copyright © 2016 John Wiley & Sons, Ltd.

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“…Thirteen boulders were 118 located in the clay-rich diamict unit and 15 were located in the sandy diamict unit ( Universities Environmental Research Centre (Xu et al, 2015). Measured sample ratios for 137 10 Be/ 9 Be (see supplemental data) are 6.6·10 -14 to 5.6·10 -13 (average analytic uncertainty 2.8 ± 0.5%, 1SD, n = 28).…”

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confidence: 99%

Constraining multi-stage exposure-burial scenarios for boulders preserved beneath cold-based glacial ice in Thule, northwest Greenland

Corbett

Bierman

Rood

2016

Earth and Planetary Science Letters

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Boulders and landscapes preserved beneath cold-based, nonerosive glacial ice violate assumptions associated with simple cosmogenic exposure dating. In such a setting, simple single isotope exposure ages over estimate the latest period of surface exposure; hence, alternate approaches are required to constrain the multi-stage exposure/burial histories of such samples. Here, we report 28 paired analyses of 10Be and 26Al in boulder samples from Thule, northwest Greenland. We use numerical models of exposure and burial as well as Monte Carlo simulations to constrain glacial chronology and infer process in this Arctic region dominated by cold-based ice. We investigate three specific cases that can arise with paired nuclide data: (1) exposure ages that are coeval with deglaciation and 26Al/10Be ratios consistent with constant exposure; (2) exposure ages that pre-date deglaciation and 26Al/10Be ratios consistent with burial following initial exposure; and (3) exposure ages that predate deglaciation and 26Al/10Be ratios consistent with constant exposure. Most glacially-transported boulders in Thule have complex histories; some were exposed for tens of thousands of years and buried for at least hundreds of thousands of years, while others underwent only limited burial. These boulders were recycled through different generations of till over multiple glacial/interglacial cycles, likely experiencing partial or complete shielding during interglacial periods due to rotation or shallow burial by sediments. Our work demonstrates that the landscape in Thule, like many high-latitude landscapes, was shaped over long time durations and multiple glacial and interglacial periods throughout the Quaternary. January 28, 2016To the Editor:After performing a second set of revisions from two reviewers, we are resubmitting our manuscript, Constraining Multi-Stage Exposure-Burial Scenarios for Boulders Preserved Beneath Cold-Based Glacial Ice in Thule, Northwest Greenland, for publication in Earth and Planetary Science Letters.We appreciated the additional comments from the two Reviewers who revisited the manuscript and are glad to hear that our first round of revisions was effective. During this second round, we focused on making the minor wording changes suggested and providing additional information about quantification of Al in samples. Attached, you will find a list of the reviewers' suggestions and details about how we incorporated those suggestions.We are optimistic that these minor revisions have finished polishing the manuscript to ready it for publication. Thank you in advance for considering our revised draft. Thank you for the re-submission of this paper and for dealing so thoroughly with the comments of the previous reviewers. As I suggested I would in my decision letter last time, I sent the revision to two of the previous reviewers. Both or these are very happy with the revision and have only minor comments.Please could you attend to the final points listed below on your revised manuscript, and then I will be able to ...

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Decadal 10Be, 26Al and 36Cl QA measurements on the SUERC 5 MV accelerator mass spectrometer

Cited by 30 publications

References 15 publications

Differential uplift and incision of the Yakima River terraces, central Washington State

Differential uplift and incision of the Yakima River terraces, central Washington State

Rates of erosion and landscape change along the Blue Ridge escarpment, southern Appalachian Mountains, estimated from in situ cosmogenic ¹⁰Be

Constraining multi-stage exposure-burial scenarios for boulders preserved beneath cold-based glacial ice in Thule, northwest Greenland

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Decadal 10Be, 26Al and 36Cl QA measurements on the SUERC 5 MV accelerator mass spectrometer

Cited by 30 publications

References 15 publications

Differential uplift and incision of the Yakima River terraces, central Washington State

Differential uplift and incision of the Yakima River terraces, central Washington State

Rates of erosion and landscape change along the Blue Ridge escarpment, southern Appalachian Mountains, estimated from in situ cosmogenic 10Be

Constraining multi-stage exposure-burial scenarios for boulders preserved beneath cold-based glacial ice in Thule, northwest Greenland

Contact Info

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Rates of erosion and landscape change along the Blue Ridge escarpment, southern Appalachian Mountains, estimated from in situ cosmogenic ¹⁰Be