20 results on '"Carrivick, J. L."'
Search Results
2. The 28 November 2020 Landslide, Tsunami, and Outburst Flood – A Hazard Cascade Associated With Rapid Deglaciation at Elliot Creek, British Columbia, Canada
- Author
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Geertsema, M., primary, Menounos, B., additional, Bullard, G., additional, Carrivick, J. L., additional, Clague, J. J., additional, Dai, C., additional, Donati, D., additional, Ekstrom, G., additional, Jackson, J. M., additional, Lynett, P., additional, Pichierri, M., additional, Pon, A., additional, Shugar, D. H., additional, Stead, D., additional, Del Bel Belluz, J., additional, Friele, P., additional, Giesbrecht, I., additional, Heathfield, D., additional, Millard, T., additional, Nasonova, S., additional, Schaeffer, A. J., additional, Ward, B. C., additional, Blaney, D., additional, Blaney, E., additional, Brillon, C., additional, Bunn, C., additional, Floyd, W., additional, Higman, B., additional, Hughes, K. E., additional, McInnes, W., additional, Mukherjee, K., additional, and Sharp, M. A., additional
- Published
- 2022
- Full Text
- View/download PDF
3. A massive rock and ice avalanche caused the 2021 disaster at Chamoli, Indian Himalaya
- Author
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Shugar, D. H., primary, Jacquemart, M., additional, Shean, D., additional, Bhushan, S., additional, Upadhyay, K., additional, Sattar, A., additional, Schwanghart, W., additional, McBride, S., additional, de Vries, M. Van Wyk, additional, Mergili, M., additional, Emmer, A., additional, Deschamps-Berger, C., additional, McDonnell, M., additional, Bhambri, R., additional, Allen, S., additional, Berthier, E., additional, Carrivick, J. L., additional, Clague, J. J., additional, Dokukin, M., additional, Dunning, S. A., additional, Frey, H., additional, Gascoin, S., additional, Haritashya, U. K., additional, Huggel, C., additional, Kääb, A., additional, Kargel, J. S., additional, Kavanaugh, J. L., additional, Lacroix, P., additional, Petley, D., additional, Rupper, S., additional, Azam, M. F., additional, Cook, S. J., additional, Dimri, A. P., additional, Eriksson, M., additional, Farinotti, D., additional, Fiddes, J., additional, Gnyawali, K. R., additional, Harrison, S., additional, Jha, M., additional, Koppes, M., additional, Kumar, A., additional, Leinss, S., additional, Majeed, U., additional, Mal, S., additional, Muhuri, A., additional, Noetzli, J., additional, Paul, F., additional, Rashid, I., additional, Sain, K., additional, Steiner, J., additional, Ugalde, F., additional, Watson, C. S., additional, and Westoby, M. J., additional
- Published
- 2021
- Full Text
- View/download PDF
4. Proglacial Lakes Control Glacier Geometry and Behavior During Recession
- Author
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Sutherland, J. L., primary, Carrivick, J. L., additional, Gandy, N., additional, Shulmeister, J., additional, Quincey, D. J., additional, and Cornford, S. L., additional
- Published
- 2020
- Full Text
- View/download PDF
5. Dune-slope activity due to frost and wind throughout the north polar erg, Mars
- Author
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Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Diniega, Serina, Hansen, Candice J., Allen, Amanda, Grigsby, Nathan, Li, Zheyu, Perez, Tyler, Chojnacki, Matthew, Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Diniega, Serina, Hansen, Candice J., Allen, Amanda, Grigsby, Nathan, Li, Zheyu, Perez, Tyler, and Chojnacki, Matthew
- Abstract
Repeat, high-resolution imaging of dunes within the Martian north polar erg have shown that these dune slopes are very active, with alcoves forming along the dune brink each Mars year. In some areas, a few hundred cubic metres of downslope sand movement have been observed, sometimes moving the dune brink ‘backwards’. Based on morphological and activity-timing similarities of these north polar features to southern dune gullies, identifying the processes forming these features is likely to have relevance for understanding the general evolution/modification of dune gullies. To determine alcove-formation model constraints, we have surveyed seven dune fields, each over 1–4 Mars winters. Consistent with earlier reports, we found that alcove-formation activity occurs during the autumn–winter seasons, before or while the stable seasonal frost layer is deposited. We propose a new model in which alcove formation occurs during the autumn, and springtime sublimation activity then enhances the feature. Summertime winds blow sand into the new alcoves, erasing small alcoves over a few Mars years. Based on the observed rate of alcove erasure, we estimated the effective aeolian sand transport flux. From this, we proposed that alcove formation may account for 2–20% of the total sand movement within these dune fields.
- Published
- 2017
6. Gully formation in the McMurdo Dry Valleys, Antarctica: multiple sources of water, temporal sequence and relative importance in gully erosion and deposition processes
- Author
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Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Dickson, James L., Head, James W., Levy, Joseph S., Morgan, Gareth A., Marchant, David R., Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Dickson, James L., Head, James W., Levy, Joseph S., Morgan, Gareth A., and Marchant, David R.
- Abstract
We report on a decade of fieldwork designed to determine the conditions required for erosion of Mars-like gully channels in the McMurdo Dry Valleys (MDV) of Antarctica. We have outlined the major factors in the morphological evolution of gullies in the Inland Mixed Zone of the MDV: (1) the distribution of ice sources; (2) the temporal aspects of ice melting; and (3) the relative significance of melting events in gullies. We show that significant erosion of gully channels can be achieved if geometrical and environmental conditions combine to concentrate ice where it can rapidly melt. In contrast, annual melting of surface ice and snow deposits during late-season discharge events contribute to transport of water, but flux rarely surpasses the infiltration capacity of the active layer. These small discharge events do not erode channels of significant width. Even when the flux is sufficient to carve a c. 10–20 cm deep channel during late summer (January–February) runoff, these small channels seldom persist through multiple seasons, because they are seasonally muted and filled with aeolian deposits. We briefly discuss the application of these results to the study of gully systems on Mars.
- Published
- 2017
7. Spatiotemporal variability of oxygen isotope compositions in three contrasting glacier river catchments in Greenland
- Author
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Yde, J. C., Knudsen, N. Tvis, Steffensen, J. P., Carrivick, J. L., Hasholt, B., Ingeman-Nielsen, T., Kronborg, C., Larsen, N. K., Mernild, S. H., Oerter, H., Roberts, D. H., Russell, A. J., Yde, J. C., Knudsen, N. Tvis, Steffensen, J. P., Carrivick, J. L., Hasholt, B., Ingeman-Nielsen, T., Kronborg, C., Larsen, N. K., Mernild, S. H., Oerter, H., Roberts, D. H., and Russell, A. J.
- Abstract
Analysis of stable oxygen isotope (δ18O) characteristics is a useful tool to investigate water provenance in glacier river systems. In order to attain knowledge on the diversity of spatio-temporal δ18O variations in glacier rivers, we have examined three glacierized catchments in Greenland with different areas, glacier hydrology and thermal regimes. At Mittivakkat Gletscher River, a small river draining a local temperate glacier in southeast Greenland, diurnal oscillations in δ18O occur with a three-hour time lag to the diurnal oscillations in runoff. Throughout the peak flow season the δ18O composition is controlled by the proportion between snowmelt and ice melt with episodic inputs of rainwater and occasional storage and release of a specific water component due to changes in the subglacial drainage system. At Kuannersuit Glacier River on the island Qeqertarsuaq, the δ18O characteristics were examined after the major 1995-1998 glacier surge event. Despite large variations in the δ18O values of glacier ice on the newly formed glacier tongue, there were no diurnal oscillations in the bulk meltwater emanating from the glacier in the post-surge years 2000-2001. In 2002 there were indications of diurnal oscillations, and in 2003 there were large diurnal fluctuations in δ18O. At Watson River, a large catchment at the western margin of the Greenland Ice Sheet, the spatial distribution of δ18O in the river system was applied to fingerprint the relative runoff contributions from sub-catchments. Spot sampling indicates that during the early melt season most of the river water (64-73 %) derived from the Qinnguata Kuussua tributary, whereas the water flow on 23 July 2009 was dominated by bulk meltwater from the Akuliarusiarsuup Kuua tributary (where 7 and 67 % originated from the Russell Glacier and Leverett Glacier sub-catchments, respectively). A comparison of the δ18O com
- Published
- 2015
8. Spatiotemporal variability of oxygen isotope compositions in three contrasting glacier river catchments in Greenland
- Author
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Yde, J. C., primary, Tvis Knudsen, N., additional, Steffensen, J. P., additional, Carrivick, J. L., additional, Hasholt, B., additional, Ingeman-Nielsen, T., additional, Kronborg, C., additional, Larsen, N. K., additional, Mernild, S. H., additional, Oerter, H., additional, Roberts, D. H., additional, and Russell, A. J., additional
- Published
- 2015
- Full Text
- View/download PDF
9. Structure from motion photogrammetry in physical geography.
- Author
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Smith, M. W., Carrivick, J. L., and Quincey, D. J.
- Subjects
- *
PHYSICAL geography , *PHOTOGRAMMETRY , *MOTION analysis , *EARTH topography , *REMOTE sensing - Abstract
Accurate, precise and rapid acquisition of topographic data is fundamental to many sub-disciplines of physical geography. Technological developments over the past few decades have made fully distributed data sets of centimetric resolution and accuracy commonplace, yet the emergence of Structure from Motion (SfM) with Multi-View Stereo (MVS) in recent years has revolutionised three-dimensional topographic surveys in physical geography by democratising data collection and processing. SfM-MVS originates from the fields of computer vision and photogrammetry, requires minimal expensive equipment or specialist expertise and, under certain conditions, can produce point clouds of comparable quality to existing survey methods (e.g. Terrestrial Laser Scanning). Consequently, applications of SfM-MVS in physical geography have multiplied rapidly. There are many practical options available to physical geographers when planning a SfM-MVS survey (e.g. platforms, cameras, software), yet, many SfM-MVS end-users are uncertain as to the errors associated with each choice and, perhaps most fundamentally, the processes actually taking place as part of the SfM-MVS workflow. This paper details the typical workflow applied by SfM-MVS software packages, reviews practical details of implementing SfM-MVS, combines existing validation studies to assess practically achievable data quality and reviews the range of applications of SfM-MVS in physical geography. The flexibility of the SfM-MVS approach complicates attempts to validate SfM-MVS robustly as each individual validation study will use a different approach (e.g. platform, camera, georeferencing method, etc.). We highlight the need for greater transparency in SfM-MVS processing and enhanced ability to adjust parameters that determine survey quality. Looking forwards, future prospects of SfM-MVS in physical geography are identified through discussion of more recent developments in the fields of image analysis and computer vision. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
10. Variable glacier response to atmospheric warming, northern Antarctic Peninsula, 1988–2009
- Author
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Davies, B. J., primary, Carrivick, J. L., additional, Glasser, N. F., additional, Hambrey, M. J., additional, and Smellie, J. L., additional
- Published
- 2012
- Full Text
- View/download PDF
11. Supplementary material to "A new glacier inventory for 2009 reveals spatial and temporal variability in glacier response to atmospheric warming in the Northern Antarctic Peninsula, 1988–2009"
- Author
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Davies, B. J., primary, Carrivick, J. L., additional, Glasser, N. F., additional, Hambrey, M. J., additional, and Smellie, J. L., additional
- Published
- 2011
- Full Text
- View/download PDF
12. A new glacier inventory for 2009 reveals spatial and temporal variability in glacier response to atmospheric warming in the Northern Antarctic Peninsula, 1988–2009
- Author
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Davies, B. J., primary, Carrivick, J. L., additional, Glasser, N. F., additional, Hambrey, M. J., additional, and Smellie, J. L., additional
- Published
- 2011
- Full Text
- View/download PDF
13. Downslope sediment transport by boiling liquid water under Mars-like conditions: experiments and potential implications for Martian gullies
- Author
-
Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Herny, Clémence, Conway, Susan J., Raack, Jan, Carpy, Sabrina, Colleu-Banse, Tanguy, Patel, Manish R., Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Herny, Clémence, Conway, Susan J., Raack, Jan, Carpy, Sabrina, Colleu-Banse, Tanguy, and Patel, Manish R.
- Abstract
Gullies are widespread morphological features on Mars for which current changes have been observed. Liquid water has been one of the potential mechanisms to explain their formation and activity. However, under present-day Martian conditions, liquid water is unstable and should only be transiently present in small amounts at the surface. Yet little attention has been paid to the mechanisms by which unstable water transports sediment under low atmospheric pressure. Here we present the results of laboratory experiments studying the interaction between liquid water flowing over a sand bed under Mars-like atmospheric pressure (c. 9 mbar). The experiments were performed in a Mars Simulation Chamber (at the Open University, UK), in which we placed a test bed of fine sand at a 25° slope. We chose to investigate the influence of two parameters: the temperature of the water and the temperature of the sand. We performed 27 experiments with nine different combinations of water and sand temperatures ranging from 278 to 297 K. Under all experimental conditions, the water was boiling. We investigated and compared the types and timing of sediment transport events, and the shapes, characteristics and volumes of the resulting morphologies. In agreement with previous laboratory studies we found that more intense boiling increased the volume of sediment transported for a given volume of water. We found four main types of sediment transport: entrainment by overland flow; grain ejection; grain avalanches; and levitation of saturated sand pellets. Our results showed that increasing sand temperature was the main driving parameter in increasing the sand transport and in modifying the dominant sediment transport mechanism. The temperature of the water played a negligible or minor role, apart from the duration of sand ejection and avalanches, which lasted longer at low water temperature. At low sand temperature the majority of the sand was transported by overland flow of the liquid water. A
14. CO2 sublimation in Martian gullies: laboratory experiments at varied slope angle and regolith grain sizes
- Author
-
Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Sylvest, Matthew E., Dixon, John C., Conway, Susan J., Patel, Manish R., McElwaine, Jim N., Hagermann, Axel, Barnes, Adam, Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Sylvest, Matthew E., Dixon, John C., Conway, Susan J., Patel, Manish R., McElwaine, Jim N., Hagermann, Axel, and Barnes, Adam
- Abstract
Martian gullies were initially hypothesized to be carved by liquid water, due to their resemblance to gullies on Earth. Recent observations have highlighted significant sediment transport events occurring in Martian gullies at times and places where CO2 ice should be actively sublimating. Here we explore the role of CO2 sublimation in mobilizing sediment through laboratory simulation. In our previous experimental work, we reported the first observations of sediment slope movement triggered by the sublimation of CO2 frost. We used a Mars regolith simulant near the angle of repose. The current study extends our previous work by including two additional substrates, fine and coarse sand, and by testing slope angles down to 10°. We find that the Mars regolith simulant is active down to 17°, the fine sand is active only near the angle of repose and the coarse sand shows negligible movement. Using an analytical model, we show that under Martian gravity motion should be possible at even lower slope angles. We conclude that these mass-wasting processes could be involved in shaping Martian gullies at the present day and intriguingly the newly reported CO2-creep process could provide an alternative explanation for putative solifluction lobes on Mars.
15. Downslope sediment transport by boiling liquid water under Mars-like conditions: experiments and potential implications for Martian gullies
- Author
-
Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Herny, Clémence, Conway, Susan J., Raack, Jan, Carpy, Sabrina, Colleu-Banse, Tanguy, Patel, Manish R., Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Herny, Clémence, Conway, Susan J., Raack, Jan, Carpy, Sabrina, Colleu-Banse, Tanguy, and Patel, Manish R.
- Abstract
Gullies are widespread morphological features on Mars for which current changes have been observed. Liquid water has been one of the potential mechanisms to explain their formation and activity. However, under present-day Martian conditions, liquid water is unstable and should only be transiently present in small amounts at the surface. Yet little attention has been paid to the mechanisms by which unstable water transports sediment under low atmospheric pressure. Here we present the results of laboratory experiments studying the interaction between liquid water flowing over a sand bed under Mars-like atmospheric pressure (c. 9 mbar). The experiments were performed in a Mars Simulation Chamber (at the Open University, UK), in which we placed a test bed of fine sand at a 25° slope. We chose to investigate the influence of two parameters: the temperature of the water and the temperature of the sand. We performed 27 experiments with nine different combinations of water and sand temperatures ranging from 278 to 297 K. Under all experimental conditions, the water was boiling. We investigated and compared the types and timing of sediment transport events, and the shapes, characteristics and volumes of the resulting morphologies. In agreement with previous laboratory studies we found that more intense boiling increased the volume of sediment transported for a given volume of water. We found four main types of sediment transport: entrainment by overland flow; grain ejection; grain avalanches; and levitation of saturated sand pellets. Our results showed that increasing sand temperature was the main driving parameter in increasing the sand transport and in modifying the dominant sediment transport mechanism. The temperature of the water played a negligible or minor role, apart from the duration of sand ejection and avalanches, which lasted longer at low water temperature. At low sand temperature the majority of the sand was transported by overland flow of the liquid water. A
16. CO2 sublimation in Martian gullies: laboratory experiments at varied slope angle and regolith grain sizes
- Author
-
Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Sylvest, Matthew E., Dixon, John C., Conway, Susan J., Patel, Manish R., McElwaine, Jim N., Hagermann, Axel, Barnes, Adam, Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., Harrison, T. N., Sylvest, Matthew E., Dixon, John C., Conway, Susan J., Patel, Manish R., McElwaine, Jim N., Hagermann, Axel, and Barnes, Adam
- Abstract
Martian gullies were initially hypothesized to be carved by liquid water, due to their resemblance to gullies on Earth. Recent observations have highlighted significant sediment transport events occurring in Martian gullies at times and places where CO2 ice should be actively sublimating. Here we explore the role of CO2 sublimation in mobilizing sediment through laboratory simulation. In our previous experimental work, we reported the first observations of sediment slope movement triggered by the sublimation of CO2 frost. We used a Mars regolith simulant near the angle of repose. The current study extends our previous work by including two additional substrates, fine and coarse sand, and by testing slope angles down to 10°. We find that the Mars regolith simulant is active down to 17°, the fine sand is active only near the angle of repose and the coarse sand shows negligible movement. Using an analytical model, we show that under Martian gravity motion should be possible at even lower slope angles. We conclude that these mass-wasting processes could be involved in shaping Martian gullies at the present day and intriguingly the newly reported CO2-creep process could provide an alternative explanation for putative solifluction lobes on Mars.
17. CO2 sublimation in Martian gullies: laboratory experiments at varied slope angle and regolith grain sizes
- Author
-
Sylvest, Matthew E., Dixon, John C., Conway, Susan J., Patel, Manish R., McElwaine, Jim N., Hagermann, Axel, Barnes, Adam, Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., and Harrison, T. N.
- Abstract
Martian gullies were initially hypothesized to be carved by liquid water, due to their resemblance to gullies on Earth. Recent observations have highlighted significant sediment transport events occurring in Martian gullies at times and places where CO2 ice should be actively sublimating. Here we explore the role of CO2 sublimation in mobilizing sediment through laboratory simulation. In our previous experimental work, we reported the first observations of sediment slope movement triggered by the sublimation of CO2 frost. We used a Mars regolith simulant near the angle of repose. The current study extends our previous work by including two additional substrates, fine and coarse sand, and by testing slope angles down to 10°. We find that the Mars regolith simulant is active down to 17°, the fine sand is active only near the angle of repose and the coarse sand shows negligible movement. Using an analytical model, we show that under Martian gravity motion should be possible at even lower slope angles. We conclude that these mass-wasting processes could be involved in shaping Martian gullies at the present day and intriguingly the newly reported CO2-creep process could provide an alternative explanation for putative solifluction lobes on Mars.
- Published
- 2019
18. Downslope sediment transport by boiling liquid water under Mars-like conditions: experiments and potential implications for Martian gullies
- Author
-
Manish R. Patel, Susan J. Conway, T. Colleu-Banse, Clémence Herny, S. Carpy, J. Raack, Physikalisches Institut [Bern], Universität Bern [Bern], Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., and Harrison, T. N.
- Subjects
Entrainment (hydrodynamics) ,Martian ,010504 meteorology & atmospheric sciences ,Atmospheric pressure ,520 Astronomy ,Sediment ,Geology ,Ocean Engineering ,Soil science ,Mars Exploration Program ,010502 geochemistry & geophysics ,620 Engineering ,01 natural sciences ,[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology ,Volume (thermodynamics) ,13. Climate action ,Boiling ,Sediment transport ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
International audience; Gullies are widespread morphological features on Mars for which current changes have been observed. Liquid water has been one of the potential mechanisms to explain their formation and activity. However, under present-day Martian conditions, liquid water is unstable and should only be transiently present in small amounts at the surface. Yet little attention has been paid to the mechanisms by which unstable water transports sediment under low atmospheric pressure. Here we present the results of laboratory experiments studying the interaction between liquid water flowing over a sand bed under Mars-like atmospheric pressure (c. 9 mbar). The experiments were performed in a Mars Simulation Chamber (at the Open University, UK), in which we placed a test bed of fine sand at a 25°slope. We chose to investigate the influence of two parameters: the temperature of the water and the temperature of the sand. We performed 27 experiments with nine different combinations of water and sand temperatures ranging from 278 to 297 K. Under all experimental conditions , the water was boiling. We investigated and compared the types and timing of sediment transport events, and the shapes, characteristics and volumes of the resulting morphologies. In agreement with previous laboratory studies we found that more intense boiling increased the volume of sediment transported for a given volume of water. We found four main types of sediment transport: entrainment by overland flow; grain ejection; grain avalanches; and levitation of saturated sand pellets. Our results showed that increasing sand temperature was the main driving parameter in increasing the sand transport and in modifying the dominant sediment transport mechanism. The temperature of the water played a negligible or minor role, apart from the duration of sand ejection and avalanches, which lasted longer at low water temperature. At low sand temperature the majority of the sand was transported by overland flow of the liquid water. At higher sand temperatures the transport was dominated by processes triggered by the boiling behaviour of the water. At the highest temperatures, sediment transport was dominated by the formation of levitating pellets, dry avalanches and ejection of the sand grains. This resulted in a transport volume about nine times greater at a sand temperature of 297 K compared with 278 K. Our heat transfer scaling shows that the boiling behaviour will be enhanced under Martian low gravity, resulting in more efficient transport of sediment by levitating sand pellets even at temperatures close to the triple point. Our results showed that the boiling intensity played an important role in the physics of sediment transport by liquid water. This implied that the amount of water required to produce morphological changes at the surface of Mars could be lower than previously estimated by assuming stable liquid water. Boiling is a critical process to be considered when assessing gully formation and modification mechanisms mobilized by liquid water. Our work could have similar implications for any water-formed landform on Mars, which could include recurring slope lineae, dark dune flows and slope streaks.
- Published
- 2018
19. Gully formation in the McMurdo Dry Valleys, Antarctica: multiple sources of water, temporal sequence and relative importance in gully erosion and deposition processes
- Author
-
Dickson, James L., Head, James W., Levy, Joseph S., Morgan, Gareth A., Marchant, David R., Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., and Harrison, T. N.
- Abstract
We report on a decade of fieldwork designed to determine the conditions required for erosion of Mars-like gully channels in the McMurdo Dry Valleys (MDV) of Antarctica. We have outlined the major factors in the morphological evolution of gullies in the Inland Mixed Zone of the MDV: (1) the distribution of ice sources; (2) the temporal aspects of ice melting; and (3) the relative significance of melting events in gullies. We show that significant erosion of gully channels can be achieved if geometrical and environmental conditions combine to concentrate ice where it can rapidly melt. In contrast, annual melting of surface ice and snow deposits during late-season discharge events contribute to transport of water, but flux rarely surpasses the infiltration capacity of the active layer. These small discharge events do not erode channels of significant width. Even when the flux is sufficient to carve a c. 10–20 cm deep channel during late summer (January–February) runoff, these small channels seldom persist through multiple seasons, because they are seasonally muted and filled with aeolian deposits. We briefly discuss the application of these results to the study of gully systems on Mars.
- Published
- 2017
20. Dune-slope activity due to frost and wind throughout the north polar erg, Mars
- Author
-
A. Allen, Matthew Chojnacki, Candice Hansen, Serina Diniega, Z. Li, N. Grigsby, T. Perez, Conway, S. J., Carrivick, J. L., Carling, P. A., de Haas, T., and Harrison, T. N.
- Subjects
Martian ,010504 meteorology & atmospheric sciences ,Geology ,Ocean Engineering ,Mars Exploration Program ,Atmospheric sciences ,01 natural sciences ,Article ,Aeolian sand ,0103 physical sciences ,Polar ,010303 astronomy & astrophysics ,Geomorphology ,Alcove ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Repeat, high-resolution imaging of dunes within the Martian north polar erg have shown that these dune slopes are very active, with alcoves forming along the dune brink each Mars year. In some areas, a few hundred cubic metres of downslope sand movement have been observed, sometimes moving the dune brink ‘backwards’. Based on morphological and activity-timing similarities of these north polar features to southern dune gullies, identifying the processes forming these features is likely to have relevance for understanding the general evolution/modification of dune gullies. To determine alcove-formation model constraints, we have surveyed seven dune fields, each over 1–4 Mars winters. Consistent with earlier reports, we found that alcove-formation activity occurs during the autumn–winter seasons, before or while the stable seasonal frost layer is deposited. We propose a new model in which alcove formation occurs during the autumn, and springtime sublimation activity then enhances the feature. Summertime winds blow sand into the new alcoves, erasing small alcoves over a few Mars years. Based on the observed rate of alcove erasure, we estimated the effective aeolian sand transport flux. From this, we proposed that alcove formation may account for 2–20% of the total sand movement within these dune fields.
- Published
- 2017
- Full Text
- View/download PDF
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