Baird, T., Bristow, C., Lou, W. et al. (4 more authors) (2021) Blowout morphometrics and mass balances. Frontiers in Earth Science, 9. 669440. ISSN 2296-6463
Abstract
The Gonghe Basin on the Qinghai-Tibet Plateau has a cold, arid climate and has suffered severe land degradation. Climate change as well as anthropogenic activities including overgrazing have resulted in widespread blowout development and the formation of some of Earth's largest blowouts. The blowouts are part of an aeolian dominated landscape that passes from deflation zone to grass covered plain, and then through blowouts of increasing size and complexity to transverse barchanoid dunes that are migrating into the valley of the Yellow River. A combination of structure-from-motion (SfM) optical drone mapping, ground-penetrating radar (GPR) and soil pits are used to investigate blowout scour hollows and depositional lobes. Comparisons of the volumes of sediment removed from the scour hollows with the volumes of sediment deposited within adjacent lobes varies between sites. The lobe volume is invariably less than the volume of the scour hollow. This can, in part, be attributed to aeolian reworking of the lobe, distributing sand further downwind and uplifting of dust. However, much of the difference in volumes between the scour and lobe can be attributed to the measurement technique, particularly where GPR was employed to calculate lobe volumes. The wavelength of the GPR limits its ability to resolve thin layers of sand resulting in an underestimate of the deposited sand at the margins of a lobe where the sand thickness is equal to, or less than, the wavelength of the GPR. For thin sand layers, beneath the resolution of the GPR, soil pits suggest a closer match between the volume of sand eroded from the scour and the volume of the lobe, albeit with large measurement uncertainty. We put forth two hypotheses to explain the spatio-temporal evolution of the blowout dune field. The downwind increase in blowout dune size could either reflect a downwind propagation of aeolian instability; or it could result from an upwind propagation of the instability, which started at the highest points in the landscape and has subsequently migrated in a northwesterly direction, towards lower elevations. Recent optically stimulated luminescence dating appear to support the latter hypothesis.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 Baird, Bristow, Luo, Du, Bryant, Mitchell and Vermeesch. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
Keywords: | Structure from motion (SFM), Qinghai - Tibet plateau, Ground Penetrating Radar (GPR), aeolian geomorphology, Geospatial Reconstruction, Blowouts |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Social Sciences (Sheffield) > Department of Geography (Sheffield) |
Funding Information: | Funder Grant number Royal Geographical Society THES 02/18 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 18 May 2021 11:18 |
Last Modified: | 25 May 2021 10:02 |
Status: | Published |
Publisher: | Frontiers Media |
Refereed: | Yes |
Identification Number: | 10.3389/feart.2021.669440 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:173838 |