# Ventifact
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{{short description|Rock that has been eroded by wind-driven sand or ice crystals}}
{{refimprove|date = April 2019}}
[[File:Ventifact at Ventifact Ridge in Death Valley NP(1).JPG|thumb|300x300px|Ventifact in [Death Valley](/source/Death_Valley).]]
A '''ventifact''' (also '''wind-faceted stone''', '''windkanter'''[Klaus K. E. Neuendorf, ''Glossary of Geology'', [https://books.google.com/books?id=yD79FqfECCYC&pg=PA723 p. 723]]) is a [rock](/source/rock_(geology)) that has been abraded, pitted, etched, grooved, or polished by wind-driven sand or ice crystals.[{{cite book|first=Julie E. |last=Laity |chapter=19. Landforms, landscapes, and processes of aeolian erosion |editor-last=Parsons|editor-first=Anthony J.|title=Geomorphology of desert environments|date=2009|publisher=Springer|location=[Dordrecht]|isbn=978-1-4020-5719-9|pages=597–628|edition=2nd.|editor2-last=Abrahams |editor2-first=Athol D.}}] The word "Ventifact" is derived from the [Latin](/source/Latin) word "Ventus" meaning '[wind](/source/wind)'. These geomorphic features are most typically found in arid environments where there is little [vegetation](/source/vegetation) to interfere with [aeolian](/source/aeolian_processes) particle transport, where there are frequently strong [winds](/source/winds), and where there is a steady but not overwhelming supply of [sand](/source/sand).
Ventifacts are formed by a variety of factors, including the type of original rock, wind speed and direction, size of aeolian particles, landscape variations, and the duration of this process, which is typically many years. They can be found in arid, [coastal](/source/Coast), and [periglacial](/source/Periglaciation) regions.[{{Cite journal |last=Várkonyi|first=Péter L.|last2=Laity|first2=Julie E.|date=2012-02-15|title=Formation of surface features on ventifacts: Modeling the role of sand grains rebounding within cavities|url=https://www.sciencedirect.com/science/article/pii/S0169555X11005472|journal=Geomorphology|volume=139-140|pages=220–229|doi=10.1016/j.geomorph.2011.10.021|issn=0169-555X}}] Studying ventifacts can lead to historical observations regarding landscape formation.[{{Cite journal |last=Hudziak|first=Samuel X.|last2=Ukstins|first2=Ingrid|last3=Peate|first3=David|last4=Whelley|first4=Patrick|last5=Scheidt|first5=Stephen|last6=Hamilton|first6=Christopher W.|date=2025-05-05|title=Improving quantitative ventifact analysis for climate investigations using the Dyngjusandur sandsheet in Iceland as a planetary analogue|url=https://www.lyellcollection.org/doi/10.1144/jgs2024-173|journal=Journal of the Geological Society|language=en|volume=182|issue=3|doi=10.1144/jgs2024-173|issn=0016-7649}}] Scientists use ventifacts to describe both [erosion](/source/erosion) processes and dominant wind patterns, which are used for both historical and future purposes. Many ventifacts on Earth are also influenced by the effects of [water](/source/water), which leads to studies on the [planet](/source/planet) [Mars](/source/Mars), where water is almost nonexistent.[{{Cite journal |last=Bridges|first=N. T.|last2=Calef|first2=F. J.|last3=Hallet|first3=B.|last4=Herkenhoff|first4=K. E.|last5=Lanza|first5=N. L.|last6=Le Mouélic|first6=S.|last7=Newman|first7=C. E.|last8=Blaney|first8=D. L.|last9=de Pablo|first9=M. A.|last10=Kocurek|first10=G. A.|last11=Langevin|first11=Y.|last12=Lewis|first12=K. W.|last13=Mangold|first13=N.|last14=Maurice|first14=S.|last15=Meslin|first15=P.‐Y.|date=2014-05-22|title=The rock abrasion record at Gale Crater: Mars Science Laboratory results from Bradbury Landing to Rocknest|url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2013JE004579|journal=Journal of Geophysical Research: Planets|language=en|volume=119|issue=6|pages=1374–1389|doi=10.1002/2013JE004579|issn=2169-9097}}]
== Types ==
Various types of features can be attributed to ventifacts, including flutes, pits, and grooves. Flutes are etched divots in the face of the rock; pits are rounded portions of the rock that have been removed; grooves are smooth, meandering carvings.[{{Cite journal |last=Durand|first=Marc|last2=Bourquin|first2=Sylvie|date=2013-03-01|title=Criteria for the identification of ventifacts in the geological record: A review and new insights|url=https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.1016/j.crte.2013.02.004/#r0150|journal=Comptes Rendus. Géoscience|language=en|volume=345|issue=3|pages=111–125|doi=10.1016/j.crte.2013.02.004|issn=1778-7025}}] These formations are caused as sand particles blown onto rocks slowly etch away at weak points in the structure. When ancient ventifacts are preserved without being moved or disturbed, they may serve as paleo-[wind](/source/wind) indicators.[{{Cite journal |last=Cheng |first=Liangqing |last2=Song |first2=Yougui |last3=Sun |first3=Huanyu |last4=Bradák |first4=Balázs |last5=Orozbaev |first5=Rustam |last6=Zong |first6=Xiulan |last7=Liu |first7=Huifang |date=2020-06-30 |title=Pronounced changes in paleo-wind direction and dust sources during MIS3b recorded in the Tacheng loess, northwest China |url=https://www.sciencedirect.com/science/article/pii/S1040618218311522 |journal=Quaternary International |series=LOESS RECORDS OF ENVIRONMENTAL CHANGE |volume=552 |pages=122–134 |doi=10.1016/j.quaint.2019.05.002 |issn=1040-6182}}] The wind direction at the time the ventifact formed will be parallel to grooves or [striations](/source/Striation_(geology)) cut into the [rock](/source/Rock_(geology)).
Common ventifact types include:
* '''Einkanters''' have one polished side[{{Cite journal |last=Knight|first=Jasper|date=2008-01-01|title=The environmental significance of ventifacts: A critical review|url=https://www.sciencedirect.com/science/article/pii/S001282520700116X|journal=Earth-Science Reviews|volume=86|issue=1|pages=89–105|doi=10.1016/j.earscirev.2007.08.003|issn=0012-8252}}] (excluding the bottom part) (the [German](/source/German_language) word 'ein' means 'one')
* '''Zweikanters''' have two polished sides (excluding the bottom part) (the [German](/source/German_language) word 'zwei' means 'two')
* '''Dreikanters''' have three polished surface (excluding the polished surface at bottom) that meet up at sharp angles[{{Cite journal |last=Knight|first=Jasper|date=2008-01-01|title=The environmental significance of ventifacts: A critical review|url=https://linkinghub.elsevier.com/retrieve/pii/S001282520700116X|journal=Earth-Science Reviews|language=en|volume=86|issue=1-4|pages=89–105|doi=10.1016/j.earscirev.2007.08.003}}] (the [German](/source/German_language) word 'drei' means 'three')
== Abrasion ==
Ventifacts commonly form in arid, coastal, and periglacial regions where there are both wind and sand particles. Arid deserts that provide abundant sand and a scarce water supply allow loose, dry sand to be transported by suspension or [saltation](/source/Saltation_(geology)), [abrading](/source/Abrasion_(geology)) rocks upon contact.[{{Cite journal |last=Knight |first=Jasper |date=2008-01-01 |title=The environmental significance of ventifacts: A critical review |url=https://www.sciencedirect.com/science/article/pii/S001282520700116X |journal=Earth-Science Reviews |volume=86 |issue=1 |pages=89–105 |doi=10.1016/j.earscirev.2007.08.003 |issn=0012-8252}}] The lack of vegetation on coasts and periglacial environments coupled with high wind speeds and particle transport lends to ventifact creation also.[[File:Weisse Wüste.jpg|thumb|right|Wind-carved "[mushroom](/source/mushroom)" shaped rocks are the centerpiece of [White Desert National Park](/source/White_Desert_National_Park), [Egypt](/source/Egypt)]]
[White Desert National Park](/source/White_Desert_National_Park) near [Farafra Oasis](/source/Farafra_Oasis) in [Egypt](/source/Egypt) experiences significant ventifact formation. Moderately tall, isolated rock outcrops ornament the landscape, eroded by saltation into [mushroom](/source/mushroom)-shaped [rock](/source/Rock_(geology)) sculptures. Saltation occurs when wind-blown [particles](/source/particles) bounce along the ground,[{{Cite journal |last=Comola|first=F.|last2=Gaume|first2=J.|last3=Kok|first3=J. F.|last4=Lehning|first4=M.|date=2019|title=Cohesion-Induced Enhancement of Aeolian Saltation|url=https://onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082195|journal=Geophysical Research Letters|language=en|volume=46|issue=10|pages=5566–5574|doi=10.1029/2019GL082195|issn=1944-8007}}] chipping away at a rock when the particles reach it. Over time, the bouncing [sand](/source/sand) grains erode the lower portions of a ventifact, leaving a larger, less-eroded cap. In certain regions, the lower rock consists of a softer makeup capped with a more wind-resistant rock on top.[{{Cite journal |last=Mashaal|first=Noha M.|last2=Sallam|first2=Emad S.|last3=Khater|first3=Tarek M.|date=2020-06-18|title=Mushroom rock, inselberg, and butte desert landforms (Gebel Qatrani, Egypt): evidence of wind erosion|url=https://link.springer.com/10.1007/s00531-020-01883-z|journal=International Journal of Earth Sciences|language=en|volume=109|issue=6|pages=1975–1976|doi=10.1007/s00531-020-01883-z|issn=1437-3254}}] The sand's highly abrasive qualities due to the particles's relatively large size lend to these configurations. The resulting products thus frequently resemble fantastical [stone](/source/stone) [mushrooms](/source/mushrooms).
== Studying ventifacts ==
=== Ventifacts on Mars ===
Ventifacts have also been discovered on [Mars](/source/Mars), where wind primarily characterizes surface distinctions due to the dry climate.[{{Cite journal |last=Bridges|first=N. T.|last2=Calef|first2=F. J.|last3=Hallet|first3=B.|last4=Herkenhoff|first4=K. E.|last5=Lanza|first5=N. L.|last6=Le Mouélic|first6=S.|last7=Newman|first7=C. E.|last8=Blaney|first8=D. L.|last9=de Pablo|first9=M. A.|last10=Kocurek|first10=G. A.|last11=Langevin|first11=Y.|last12=Lewis|first12=K. W.|last13=Mangold|first13=N.|last14=Maurice|first14=S.|last15=Meslin|first15=P.‐Y.|date=2014-05-22|title=The rock abrasion record at Gale Crater: Mars Science Laboratory results from Bradbury Landing to Rocknest|url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2013JE004579|journal=Journal of Geophysical Research: Planets|language=en|volume=119|issue=6|pages=1374–1389|doi=10.1002/2013JE004579|issn=2169-9097}}] The lack of moisture on the planet allows for studies observing the sole effects of wind and particles in the formation of ventifacts. During an exploration, the [''Curiosity'' rover](/source/Curiosity_(rover))[NASA, [https://llis.nasa.gov/lesson/22401 Premature Wear of the MSL Wheels], 2017-09-26] was reported to have experienced significant damage to its wheels due to sharp immobile rocks, or ventifacts. Other [rovers](/source/Rover_(space_exploration)), including "Mars Exploration Rover," and "Spirit," have also traversed the planet's landscape, locating ventifacts and other landforms.[{{Cite journal |last=Laity|first=Julie E.|last2=Bridges|first2=Nathan T.|date=2009-04-15|title=Ventifacts on Earth and Mars: Analytical, field, and laboratory studies supporting sand abrasion and windward feature development|url=https://www.sciencedirect.com/science/article/pii/S0169555X08004340|journal=Geomorphology|volume=105|issue=3|pages=202–217|doi=10.1016/j.geomorph.2008.09.014|issn=0169-555X}}][{{Cite journal |last=Bridges|first=N. T.|last2=Calef|first2=F. J.|last3=Hallet|first3=B.|last4=Herkenhoff|first4=K. E.|last5=Lanza|first5=N. L.|last6=Le Mouélic|first6=S.|last7=Newman|first7=C. E.|last8=Blaney|first8=D. L.|last9=de Pablo|first9=M. A.|last10=Kocurek|first10=G. A.|last11=Langevin|first11=Y.|last12=Lewis|first12=K. W.|last13=Mangold|first13=N.|last14=Maurice|first14=S.|last15=Meslin|first15=P.‐Y.|date=2014-05-22|title=The rock abrasion record at Gale Crater: Mars Science Laboratory results from Bradbury Landing to Rocknest|url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2013JE004579|journal=Journal of Geophysical Research: Planets|language=en|volume=119|issue=6|pages=1374–1389|doi=10.1002/2013JE004579|issn=2169-9097}}] A specific ventifact named [Jake Matijevic](/source/Jake_Matijevic_(rock)) has been used as a reference point for mapping Martian terrain and measuring weathering effects.[{{Cite journal |last=Bridges|first=N. T.|last2=Calef|first2=F. J.|last3=Hallet|first3=B.|last4=Herkenhoff|first4=K. E.|last5=Lanza|first5=N. L.|last6=Le Mouélic|first6=S.|last7=Newman|first7=C. E.|last8=Blaney|first8=D. L.|last9=de Pablo|first9=M. A.|last10=Kocurek|first10=G. A.|last11=Langevin|first11=Y.|last12=Lewis|first12=K. W.|last13=Mangold|first13=N.|last14=Maurice|first14=S.|last15=Meslin|first15=P.‐Y.|date=2014-05-22|title=The rock abrasion record at Gale Crater: Mars Science Laboratory results from Bradbury Landing to Rocknest|url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2013JE004579|journal=Journal of Geophysical Research: Planets|language=en|volume=119|issue=6|pages=1374–1389|doi=10.1002/2013JE004579|issn=2169-9097}}]
=== Wind tunnel experiments ===
Ventifacts have been studied through the execution of wind tunnel experiments. Wind tunnels operate as artificial environments with variables that can be controlled and measured. The Trent Environmental Wind Tunnel is based on [Ralph Bagnold](/source/Ralph_Bagnold)'s previous experiments with wind tunnels.[{{Cite journal |last=McKenna Neuman|first=Cheryl|last2=Gillies|first2=John A.|last3=O'Brien|first3=Patrick|last4=Saarenvirta|first4=Gianna|last5=Nickling|first5=William G.|date=2023-03-15|title=Development of ornamentation on ventifacts: An examination of flow and saltation kinematic mechanisms|url=https://onlinelibrary.wiley.com/doi/10.1002/esp.5502|journal=Earth Surface Processes and Landforms|language=en|volume=48|issue=3|pages=555–568|doi=10.1002/esp.5502|issn=0197-9337}}] [Ralph Bagnold](/source/Ralph_Bagnold) (1896-1990) was a British [geologist](/source/geologist) who pioneered studies on aeolian processes through wind tunnel experiments.[{{Cite journal |last=Bridges|first=Nathan T.|last2=Ehlmann|first2=Bethany L.|date=2017-09-18|title=The Mars Science Laboratory (MSL) Bagnold Dunes Campaign, Phase I: Overview and introduction to the special issue|url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2017JE005401|journal=Journal of Geophysical Research: Planets|language=en|volume=123|issue=1|pages=3–19|doi=10.1002/2017JE005401|issn=2169-9097|archive-url=http://web.archive.org/web/20250528161003/https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2017JE005401|archive-date=2025-05-28}}] He crossed the [Libyan Desert](/source/Libyan_Desert) during his service in the [British Army](/source/British_Army), eventually publishing a book based on his studies of the effects of the wind and sand.[{{Cite web |last=Bagnold|first=Ralph A.|date=2026-02-23|title=Wind-Tunnel Observations|url=https://link.springer.com/chapter/10.1007/978-94-009-5682-7_3|website=Springer Nature Link}}]
[NASA's](/source/NASA) Titan Wind Tunnel is used to test aeolian processes on various planets.[{{Cite journal |last=Burr|first=Devon M.|last2=Bridges|first2=Nathan T.|last3=Smith|first3=James K.|last4=Marshall|first4=John R.|last5=White|first5=Bruce R.|last6=Williams|first6=David A.|date=2015-09-01|title=The Titan Wind Tunnel: A new tool for investigating extraterrestrial aeolian environments|url=https://www.sciencedirect.com/science/article/pii/S1875963715000695|journal=Aeolian Research|volume=18|pages=205–214|doi=10.1016/j.aeolia.2015.07.008|issn=1875-9637}}][{{Cite journal |last=Burr|first=Devon M.|last2=Sutton|first2=Stephen L. F.|last3=Emery|first3=Joshua P.|last4=Nield|first4=Emily V.|last5=Kok|first5=Jasper F.|last6=Smith|first6=James K.|last7=Bridges|first7=Nathan T.|date=2020-08-01|title=A wind tunnel study of the effect of intermediate density ratio on saltation threshold|url=https://www.sciencedirect.com/science/article/pii/S1875963720300525|journal=Aeolian Research|volume=45|article-number=100601|doi=10.1016/j.aeolia.2020.100601|issn=1875-9637|via=Science Direct}}] The wind tunnel consists of multiple closely measured chambers, with controlled variables including pressure, wind, and [gas](/source/gas) composition. This allows for realistic representations of the varying planetary [atmospheres](/source/Atmosphere).[{{Cite journal |last=Burr|first=Devon M.|last2=Bridges|first2=Nathan T.|last3=Smith|first3=James K.|last4=Marshall|first4=John R.|last5=White|first5=Bruce R.|last6=Williams|first6=David A.|date=2015-09-01|title=The Titan Wind Tunnel: A new tool for investigating extraterrestrial aeolian environments|url=https://www.sciencedirect.com/science/article/pii/S1875963715000695|journal=Aeolian Research|volume=18|pages=205–214|doi=10.1016/j.aeolia.2015.07.008|issn=1875-9637}}] Specific observations about the ventifact formation can be gathered from the data, such as the saltation threshold, when wind begins to move particles, and impact threshold.[{{Cite journal |last=Burr|first=Devon M.|last2=Sutton|first2=Stephen L. F.|last3=Emery|first3=Joshua P.|last4=Nield|first4=Emily V.|last5=Kok|first5=Jasper F.|last6=Smith|first6=James K.|last7=Bridges|first7=Nathan T.|date=2020-08-01|title=A wind tunnel study of the effect of intermediate density ratio on saltation threshold|url=https://www.sciencedirect.com/science/article/abs/pii/S1875963720300525|journal=Aeolian Research|volume=45|via=Science Direct}}]
file:Mendenhall 1905 USGS.jpg|[Schist](/source/Schist) boulder pitted by sand blast near Palm Springs Station, [Colorado Desert](/source/Colorado_Desert). [Riverside County](/source/Riverside_County), [California](/source/California) (Mendenhall, 1905)
file:VentifactMojaveDesert031511.jpg|Ventifact from the [Mojave Desert](/source/Mojave_Desert) near [Barstow](/source/Barstow%2C_California), [California](/source/California).
file:Ventifact_at_Ventifact_Ridge_in_Death_Valley.jpg|Ventifact at Ventifact Ridge in [Death Valley](/source/Death_Valley) (Mayer, 2003)
file:Bradley_1930_dreikanter.jpg|[Granite](/source/Granite) dreikanter polished by windblown sand, [Sweetwater County](/source/Sweetwater_County), Wyoming ([Bradley](/source/W._H._Bradley), 1930)
file:Segerstrom_1962_USGSProPaper450C.jpg|Outcrop of [granite](/source/granite) that has been undercut by the abrasive action of windblown sand, Llano de [Caldera](/source/Caldera), [Atacama](/source/Atacama_Desert) Province, [Chile](/source/Chile) (Segerstrom, 1962)
file:Yardang Lea-Yoakum Dunes.jpg|Wind-carved, [sandstone](/source/sandstone) [yardang](/source/yardang) in a [blowout](/source/Blowout_(geology)) near [Meadow, Texas](/source/Meadow%2C_Texas) (Stout, 2002)
file:Im Salar de Uyuni.jpg|The [Árbol de Piedra](/source/%C3%81rbol_de_Piedra) is a 7-metre-tall ventifact in the [Altiplano](/source/Altiplano) region of [Bolivia](/source/Bolivia) (Wilken, 2002).
==See also==
*{{annotated link|Arkenu structures}}
*{{annotated link|Blowout (geomorphology)}}
*{{annotated link|Dune}}
*{{annotated link|Yardang}}
*{{annotated link|Ventifact Knobs}}, Antarctica
== References ==
{{reflist}}
==External links==
{{commonscat|Ventifact}}
*{{URL|https://data.mendeley.com/datasets/675gwk5jp7/1|The Bibliography of Aeolian Research}}
{{Authority control}}
Category:Aeolian landforms
Category:Petrology
Category:Rocks
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Adapted from the Wikipedia article [Ventifact](https://en.wikipedia.org/wiki/Ventifact) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Ventifact?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.