Difference between revisions 2240732 and 2241190 on enwikiversity

[[Image:Chain of impact craters on Ganymede.jpg|thumb|right|250px|The image shows a chain of craters on Ganymede. Credit: Galileo Project, Brown University, JPL, NASA.]]
A '''crater''' may be any large, roughly circular, depression or hole in or beneath the rocky surface of a rocky object.

(contracted; show full)|accessdate=
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Minute amounts of stishovite has been found within diamonds.<ref name=Wirth>{{ cite journal
|doi=10.1016/j.epsl.2007.04.041
|title=Inclusions of nanocrystalline hydrous aluminium silicate "Phase Egg" in superdeep diamonds from Juina (Mato Grosso State, Brazil)
|year=2007
|author=R Wirth
, C. Vollmer, F. Brenker, S. Matsyuk, ⏎
|author2=C. Vollmer
|author3=F. Brenker
|author4=S. Matsyuk
|author5=F. Kaminsky
|journal=Earth and Planetary Science Letters
|volume=259
|pages=384
|bibcode=2007E&PSL.259..384W
|issue=3–4 }}</ref>

The major evidence for a volcanic origin for tektites "includes: close analogy between shaped tektites and small volcanic bombs, and between layered tektites and lava or tuff-lava flows or huge bombs; analogy between flanged tektites and volcanic bombs ablated by gasjets: long-time, multistage formation of some tektites that corresponds to wide variations in their radiometric ages; well-ordered long compositional trends (series) typical of magmatic differentiation; different compositional tektite families (subseries) comparable to different stages (phases) of the volcanic process."<ref name=Izokh>{{ cite journal
|author=EP Izokh
|title=Origin of tektites: an alternative to terrestrial impact theory
|journal=Chemie der Erde : Beitrage zur Chemischen Mineralogie, Petrographie und Geologie
|month=
|year=1996
|volume=56
|issue=
|pages=458-74
|url=http://ukpmc.ac.uk/abstract/MED/11541098
|arxiv=
|bibcode=
|doi=
|pmid=11541098
|accessdate=2012-10-23 }}</ref>

"As with the North American microtektite-bearing cores, all the Australasian microtektite-bearing cores containing coesite and shocked quartz also contained volcanic ash, which complicated the search."<ref name=Glass>{{ cite journal
|author=B. P. Glass and ⏎
|author2=Jiquan Wu
|title=Coesite and shocked quartz discovered in the, Australasian and North American, microtektite layers
|journal=Geology
|month=May
|year=1993
|volume=21
|issue=5
|pages=435-8
|url=http://geology.geoscienceworld.org/content/21/5/435.short
|arxiv=
|bibcode=
|doi=10.1130/0091-7613(1993)021<0435:CASQDI>2.3.CO;2
|pmid=
|accessdate=2012-10-23 }}</ref>
{{clear}}

==Theoretical crater astronomy==
[[Image:Mount Mazama eruption timeline.PNG|thumb|right|250px|Example of the formation of a caldera, the pictures show Mount Mazama's eruption timeline. Credit: .]]
A "cataclysm [may] have affected the entire inner Solar System ... [when] numerous main-belt asteroids ... were driven onto high-velocity and highly eccentric orbits by the effects of the late migration of the giant planets."<ref name=Marchi>{{ cite journal
|author=S. Marchi, ⏎
|author2=W. F. Bottke, ⏎
|author3=B. A. Cohen, ⏎
|author4=K. Wünnemann, ⏎
|author5=D. A. Kring, ⏎
|author6=H. Y. McSween, ⏎
|author7=M. C. De Sanctis, ⏎
|author8=D. P. O’Brien, P. Schenk, ⏎
|author9=P. Schenk
|author10=C. A. Raymond & ⏎
|author11=C. T. Russell
|title=High-velocity collisions from the lunar cataclysm recorded in asteroidal meteorites
|journal=Nature Geoscience
|month=March
|year=2013
|volume=6
|issue=4
|pages=303-7
(contracted; show full)

is called a '''stratum''', plural '''strata'''.

Natural bombs may produce impact craters and deform rock strata.

"There is no correlation between n (the exponent for the change in particle diameter) and any of the other entities, which shows that n-values cannot be used as an index of maturation of a soil."<ref name=Jordan>{{ cite journal
|author=J.L. Jordan
, ⏎
|author2=J.R. Walton, D. Heymann, & ⏎
|author3=D. Heymann
|author4=S. Lakatos
|title=The Rim of North Ray Crater: A Relatively Young Regolith
|journal=Abstracts of the Lunar and Planetary Science Conference
|month=March
|year=1974
|volume=5
|issue=03
|pages=388
(contracted; show full)

'''S P Crater''' is a cinder cone volcano in the San Francisco volcanic field, {{convert|25|mi|km|0}} north of Flagstaff, Arizona.<ref name=Priest>{{ cite book
| author = Susan S. Priest
, ⏎
|author2=Wendell A. Duffield, ⏎
|author3=Karen Malis-Clark, ⏎
|author4=James W. Hendley II, and ⏎
|author5=Peter H. Stauffer
| title = The San Francisco Volcanic Field, Arizona: USGS Fact Sheet 017-01
| publisher = United States Geological Survey
| date = 2001-12-21
| url = http://geopubs.wr.usgs.gov/fact-sheet/fs017-01/
| accessdate = 2008-09-02 }}</ref> It is surrounded by several other cinder cones which are older and more eroded. It is a striking feature on the local landscape, with a well-defined lava flow that extends for {{convert|7|km|mi|1|sp=us}} to the north.<ref name=Lopes>{{ cite book
(contracted; show full)|journal=Geological Society of America Bulletin
|volume=118
|issue=3-4
|pages=421-9
|year= 2006 }}</ref> and the un-weathered young appearance of the cone.

"Independently of other criteria the distribution of the KIT boundary ejecta predicts that the Chicxulub crater is the K/T source crater."<ref name=Hildebrand>{{ cite journal
|author=A.R. Hildebrand
, ⏎
|author2=J.A. Stansberry
|title=K/T boundary ejecta distribution predicts size and location of Chicxulub crater
|journal=Abstracts of the Lunar and Planetary Science Conference
|month=March
|year=1992
|volume=23
|issue=03
|pages=537
|url=http://adsabs.harvard.edu/full/1992LPI....23..537H
|arxiv=
|bibcode=1992LPI....23..537H
|doi=
|pmid=
|accessdate=2013-10-18 }}</ref>

"In agreement with many authors (Pal et al., 1982; Klein and Middleton, 1984; Blum et al., 1992), we therefore exclude meteoritic and lunar material as sources for the <sup>10</sup>Be in the Australasian tektites, and, by a short extension, for virtually all the other atoms in the tektites."<ref name=Ma>{{ cite journal
|author=P. Ma, K. Aggrey, C. Tonzola, ⏎
|author2=K. Aggrey
|author3=C. Tonzola
|author4=C. Schnabel, ⏎
|author5=P. de Nicola, ⏎
|author6=G.F. Herzog, ⏎
|author7=J.T. Wasson, B.P. Glass, L. Brown, F. Tera, ⏎
|author8=B.P. Glass
|author9=L. Brown
|author10=F. Tera
|author11=R. Middleton, ⏎
|author12=J. Klein
|title=Beryllium-10 in Australasian tektites: constraints on the location of the source crater
|journal=Geochimica et Cosmochimica Acta
|month=October
|year=2004
|volume=68
|issue=19
|pages=3883-96
(contracted; show full)|arxiv=
|bibcode=
|doi=
|pmid=
|accessdate=2013-10-18 }}</ref>

"Phoebe is a densely cratered object. Cumulative numbers of craters, between 100 m and 100 km diameter, per unit area, define a steep-sloped curve (Fig. 5). Crater densities approach those seen on other heavily cratered objects (15, 16)."<ref name=Porco>{{ cite journal
|author=C. C. Porco1
, E. Baker, J. Barbara, K. Beurle, A. Brahic, J. A. Burns, S. Charnoz, N. Cooper, ⏎
|author2=E. Baker
|author3=J. Barbara
|author4=K. Beurle
|author5=A. Brahic
|author6=J. A. Burns
|author7=S. Charnoz
|author8=N. Cooper
|author9=D. D. Dawson, ⏎
|author10=A. D. Del Genio, T. Denk, L. Dones, U. Dyudina, M. W. Evans, B. Giese, K. Grazier, ⏎
|author11=T. Denk
|author12=L. Dones
|author13=U. Dyudina
|author14=M. W. Evans
|author15=B. Giese
|author16=K. Grazier
|author17=P. Helfenstein, ⏎
|author18=A. P. Ingersoll, ⏎
|author19=R. A. Jacobson, ⏎
|author20=T. V. Johnson, A. McEwen, C. D. Murray, G. Neukum, W. M. Owen, J. Perry, T. Roatsch, J. Spitale, S. Squyres, ⏎
|author21=A. McEwen
|author22=C. D. Murray
|author23=G. Neukum
|author24=W. M. Owen
|author25=J. Perry
|author26=T. Roatsch
|author27=J. Spitale
|author28=S. Squyres
|author29=P. C. Thomas, ⏎
|author30=M. Tiscareno, E. Turtle, A. R. Vasavada, J. Veverka, R. Wagner, ⏎
|author31=E. Turtle
|author32=A. R. Vasavada
|author33=J. Veverka
|author34=R. Wagner
|author35=R. West
|title=Cassini imaging science: Initial results on Phoebe and Iapetus
|journal=Science
|month=February
|year=2005
|volume=307
|issue=5713
|pages=1237-42
(contracted; show full)and its alinement with Davy G strongly support, in this writer's opinion, a volcanic origin. Also arguing against a secondary impact origin is the fact that the Davy chain is a lone feature. There are no other similar chains with this trend in the area. As was shown earlier in this chapter (figs. 124 and 125), secondary crater chains tend to occur in large numbers within the belt of secondary craters surrounding a large primary crater."<ref name=Masursky>{{ cite book
|author=Harold Masursky
, ⏎
|author2=G. W. Colton, and ⏎
|author3=Farouk El-Baz
|title=APOLLO OVER THE MOON: A VIEW FROM ORBIT (NASA SP-362), Cahpter 5: Craters (3/6)
|publisher=NASA Headquarters
|location=Washington, DC USA
|date=December 1978
|url=http://www.hq.nasa.gov/office/pao/History/SP-362/ch5.3.htm
|accessdate=2013-03-31 }}</ref>

“Electrical currents flow in [plasmas], punching into long filaments and then braiding themselves into ropelike structures. These long, twisted filaments are visible in solar prominences, galactic jets, and comet tails. They were detected as “stringy things” in the forty-million-kilometer-long tail of Venus last year.”<ref name=Acheson>{{ cite book
|author=Mel and Acheson
|author2=Amy Acheson
|title=Thunderbolts of the Gods: Does Growing Evidence of an Electric Universe Reveal Previously Hidden Meaning in ancient Mythology?, In: ''Forbidden History Prehistoric Technologies, Extraterrestrial Intervention, and the Suppressed Origins of Civilization''
|publisher=Bear & Company
|location=Rochester, Vermont
|date=2005
|editor=J. Douglas Kenyon
|pages=69-77
(contracted; show full)
{{clear}}

==Continua==
{{main|Radiation astronomy/Continua|Continuum astronomy|Continua}}
"Croft [3] called moat craters anomalous pit craters and also suggested a continuum between moat craters, craters, and palimpsests, even though morphometrically they appeared to be distinct."<ref name=Lucchitta>{{ cite journal
|author=B.K. Lucchitta
 and ⏎
|author2=H.M. Ferguson
|title=Ganymede: "Moat" Craters Compared with Palimpsests and Basins
|journal=Abstracts of the Lunar and Planetary Science Conference
|month=March
|year=1988
|volume=19
|issue=03
|pages=701
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Removal of material and rock beneath a surface may result in a collapse of material above into the cavern below.

"In accordance with its definition, a makhtesh (Hebrew for "mortar" or "crater"; plural, makhteshim) is an erosion structure incised into an anticline and having a single drainage system with one outlet."<ref name=Insarov>{{ cite journal
|author=Gregory Insarov
 & ⏎
|author2=Irina Insarova
|title=The lichens of calcareous rocks in the Central Negev, Israel
|journal=Israel Journal of Plant Sciences
|month=
|year=1995
|volume=43
|issue=1
|pages=53-62
|url=http://www.tandfonline.com/doi/abs/10.1080/07929978.1995.10676590
|arxiv=
|bibcode=
|doi=10.1080/07929978.1995.10676590
|pmid=
|accessdate=2013-10-16 }}</ref>

"Erosional craters (Makhtesh) were formed by truncation and erosion of several of these anticlinal crests."<ref name=Fruchter>{{ cite journal
|author=N. Fruchter, A. Matmon, Y. Avni, ⏎
|author2=A. Matmon
|author3=Y. Avni
|author4=D. Fink
|title=Revealing sediment sources, mixing, and transport during erosional crater evolution in the hyperarid Negev Desert, Israel
|journal=Geomorphology
|month=November 15,
|year=2011
|volume=134
|issue=3-4
|pages=363-77
(contracted; show full)
|author=US Geological Survey
|title=Iowa Meteorite Crater Confirmed
|url=http://www.usgs.gov/newsroom/article.asp?ID=3521|accessdate=7 March 2013 }}</ref>

At right is a "[r]ecent airborne geophysical surveys near Decorah, Iowa [which is] providing an unprecedented look at a 470- million-year-old meteorite crater concealed beneath bedrock and sediments."<ref name=Koontz>{{ cite book
|author=Heidi Koontz
 and ⏎
|author2=Robert McKay
|title=Iowa Meteorite Crater Confirmed
|publisher=U.S. Geological Survey
|location=12201 Sunrise Valley Dr, MS 119 Reston, Virginia 20192 USA
|date=March 5, 2013
|url=http://www.usgs.gov/newsroom/article.asp?ID=3521#.UVfS467Qorc
|accessdate=2013-03-30 }}</ref>

(contracted; show full) thousand impact craters on Venus are evenly distributed across its surface. On Venus, about 85% of the craters are in pristine condition. Venusian craters range from 3&nbsp;km to 280&nbsp;km in diameter. No craters are smaller than 3&nbsp;km, because of the effects of the dense atmosphere on incoming objects. Objects with less than a certain kinetic energy are slowed down so much by the atmosphere, they do not create an impact crater.<ref name=Herrick>{{cite journal
|author=R. R. Herrick
, ⏎
|author2=R. J. Phillips
|year=1993
|title=Effects of the Venusian atmosphere on incoming meteoroids and the impact crater population
|journal=Icarus
|volume=112
|issue=1
|pages=253–281
|doi=10.1006/icar.1994.1180
(contracted; show full)

"Collisions by fragmented objects result in multiple impacts that can lead to the formation of linear crater chains, or catenae, on planetary surfaces<sup>2</sup>."<ref name=Spray>{{ cite journal
|author=John G. Spray
, ⏎
|author2=Simon P. Kelley & ⏎
|author3=David B. Rowley
|title=Evidence for a late Triassic multiple impact event on Earth
|journal=Nature
|month=12 March
|year=1998
|volume=392
|issue=6672
|pages=171-3
(contracted; show full)|publisher=NASA/JPL-Caltech/MIT/GSFC
|location=
|date=December 6, 2012
|url=http://www.nasa.gov/mission_pages/grail/multimedia/zuber4.html
|accessdate=2012-12-15 }}</ref>

"Crystallized spheres of orange glass from Shorty Crater at the Apollo 17 site are ... the characteristic ingredient of the dark mantling deposit of the Taurus-Littrow region."<ref name=Adams>{{ cite journal
|author=John B. Adams
, ⏎
|author2=Carle Pieters, and ⏎
|author3=Thomas B. McCord
|title=Orange glass: Evidence for regional deposits of pyroclastic origin on the moon, In: ''Proceedings of the Fifth Lunar Science Conference''
|publisher=Pergamon Press, Inc.
|location=New York
|month=March 18-22
|year=1974
|editor=
|volume=1
|issue=
|pages=171-86
|url=http://adsabs.harvard.edu//abs/1974LPSC....5..171A
|arxiv=
|bibcode=1974LPSC....5..171A
|doi=
|pmid=
|isbn=
|accessdate=2012-11-02 }}</ref>

"A 1953 telescopic photograph of a flash on the Moon is the only unequivocal record of the rare crash of an asteroid-sized body onto the lunar surface. ... A search of images from the Clementine mission reveals an ∼1.5-km high-albedo, blue, fresh-appearing crater with an associated ejecta blanket at the location of the flash."<ref name=Buratti>{{ cite journal
|author=Bonnie J Buratti, ⏎
|author2=Lane L Johnson
|title=Identification of the lunar flash of 1953 with a fresh crater on the moon’s surface
|journal=Icarus
|month=January
|year=2003
|volume=161
|issue=1
|pages=192-7
(contracted; show full)
{{clear}}

==Vesta==
{{main|Wanderers/Vesta|Vesta}}
"The [NASA's Dawn spacecraft] Framing Camera (FC) discovered enigmatic orange material on Vesta. FC images revealed diffuse orange ejecta around two impact craters, 34-km diameter Oppis, and 30-km diameter Octavia, as well as numerous sharp-edge orange units in the equatorial region."<ref name=Corre>{{ cite journal
|author=L Le Corre
, V Reddy, ⏎
|author2=V Reddy
|author3=KJ Becker
|title=Nature of Orange Ejecta Around Oppia and Octavia Craters on Vesta from Dawn Framing Camera
|journal=American Astronomical Society, DPS meeting
|month=October
|year=2012
|volume=
|issue=44
|pages=
(contracted; show full)

Cratering is seen on both types of terrain [third image at right], but is especially extensive on the dark terrain: it appears to be saturated with impact craters and has evolved largely through impact events.<ref name=Showman1999>{{ cite journal
|author=Adam P. Showman
, ⏎
|author2=Renu Malhotra
|title=The Galilean Satellites
|year=1999
|journal=Science
|volume=286
|pages=77&ndash;84
|doi=10.1126/science.286.5437.77
| url=http://www.lpl.arizona.edu/~showman/publications/showman-malhotra-1999.pdf
|pmid=10506564
|issue=5437 }}</ref> The brighter, grooved terrain contains many fewer impact features, which have been only of a minor importance to its tectonic evolution.<ref name=Showman1999/> The density of cratering indicates an age of 4&nbsp;billion years for the dark terrain, similar to the highlands of the [[Moon/Keynote lecture|Moon]], and a somewhat younger age for the grooved terrain (but how much younger is uncertain).<ref name=Zahnle1998>{{ cite journal
|author=K. Zahnle, ⏎
|author2=L. Dones
|title=Cratering Rates on the Galilean Satellites
|journal=Icarus
|year=1998
|volume=136
|issue=2
|pages=202&ndash;22
|doi=10.1006/icar.1998.6015
(contracted; show full)|year=2004
|doi=10.1016/j.icarus.2003.11.013
|bibcode=2004Icar..169..140L}}</ref>

Several volcanoes produce plumes of sulfur and sulfur dioxide that climb as high as 500 km (300 mi) above the surface.

Seven of the nine plumes observed in March were still active in July 1979, with only the volcano Pele shutting down between flybys [of Voyager 1 then Voyager 2].<ref name="Strom1982">{{cite book
|author=R. G. Strom
 and ⏎
|author2=Schneider, N. M.
|editor=Morrison, D.
|title=Volcanic eruptions on Io, In: ''Satellites of Jupiter''
|date=1982
|publisher=University of Arizona Press
|isbn=0-8165-0762-7
|pages=598–633
}}</ref>
(contracted; show full)[[Category:Earth sciences/Lectures]]
[[Category:Geography/Lectures]]
[[Category:Geology/Lectures]]
[[Category:Materials sciences/Lectures]]
[[Category:Planetary sciences/Lectures]]
[[Category:Radiation/Lectures]]
[[Category:Radiation astronomy/Lectures]]
[[Category:Resources last modified in January 2020]]