Like the other planets, Earth formed . -Un+iJiO&Jsg/kO(*g!FcyvOC&t+3I*cm_5{`7=!MhW&A\8(}HOf%_Pp)G)d:owWt..L PAGE 3 PAGE 1 ! It measures 85.9 kilometers in diameter and was named after Dirk Reuyl, a Dutch-American physicist and astronomer (19061972) who made astronomical measurements of the diameter of Mars in the 1940s.[1]. Fig. Sinuous Ridge Materials in Reuyl Crater. Sand and dust particles carried by the wind form dunes and windstreaks. The dark brown to black color is the most obvious characteristic. Given such drastic, far-reaching outcomes of space rock impacts, Kring said that studying crater formation holds the answer to understand not only how life on Earth began but also how it could be wiped away again in a future, perhaps inevitable, K-T event. Fig. Indeed, impact craters are one of the most common geological landforms on the majority of rocky terrestrial planets, asteroids, and many of the rocky and icy moons of the inner and outer Solar System. Below a trajectory defining floor and walls of the expanding cavity, the rock material cannot leave and is compressed sideward and downwards. A stone-into-mud crater demonstrates the difference between it and a hypervelocity crater (Fig. The largest impact basin on the Moon is 2500 kilometers (1550 miles) in diameter and more than 12 kilometers (7 miles) deep. stream Measure and record the east-west and north-south diameters. Slaty cleavage is composed of platy minerals that are too small to see. For very large impact craters, the excavation and modification stages are not as discrete as previously written. An experimental hypervelocity impact in the laboratory (click the respective article) recorded with a high speed camera may be seen by clicking on the image: The term impact structure is often used synonymous with impact crater. This means that our own planet is one of the youngest in the Solar System. Firsoff is an impact crater in the region called Meridiani Planum in the Oxia Palus quadrangle of Mars, located at 2.66N latitude and 9.42W longitude.It is 90 km in diameter. Coquina and limestone are both composed of calcite. In the large 35-40 km-diameter Azuara, Spain impact structure there is stratigraphic evidence for such a nearly simultaneous excavation and collapse [click here]. %PDF-1.4 % Not commonly seen in most introductory lab samples.FractureBreakage of a mineral, not along planes of weakness in the crystral structure.Examine the mineral for areas where the mineral is broken. Typically the large crystals (phenocrysts) are visible while the smaller crystal are not (referred to as groundmass). > h] bjbj!! Barringer Crater (Meteor Crater) in Arizona, United States, is a simple crater created when a 50-meter-wide (160-foot-wide) iron-rich meteroid struck Earth's surface about 50,000 years ago a very recent event to a geologist. Typically, materials from space hit Earth at about 20 kilometers (slightly more than 12 miles) per second. This process is comparable to the transition from alluvial fan to debris flow-like evidence reported in the Harris crater, . <> Nrdlinger Ries. They are typically filled with impact rocks (impactites) in the form of impact melt rocks,suevitesand different kinds ofbreccias. Consider the relationship between Ma'adim Vallis and Gusev, the 160 km diameter . largest craters on Europa, Ganymede, and Callisto formed in an icy crust (Io's crust is dominated by silicates, see Chap ter 14). Fig. Dual crater at the bottom of Lake Chiemsee, Bavaria (Germany) that very probably formed in the large Holocene Chiemgau impact event. But the environmental effects of impact crater formation go far beyond forming benign basins. The number of very large craters in the southern highlands implies a substantial age for the surface. Large crustal blocks were merging together to create the . Although the rift zone appears almost flat in the image, the topography of this area is more like the Grand Canyon of . Thus, if a valley cuts through a crater, the crater must be older. <>>> Justify your answer. 288 pp, The University of Arizona Press, Tucson, 1986. Privacy Policy| eige6 Reuyl Crater Central Peak, as seen by HiRISE. Approximately 80% of Earth's surface is less than 200 million years old, while over 99% of the Moon's surface is more than 3 billion years old. These conditions only occur with larger projectiles (a few hundred tons and more) that are not significantly slowed down by friction in the atmosphere that impact the ground at cosmic velocities (10 70 km/s). The inner walls of the crater have collapsed to form a series of step-like terraces, and a central peak is visible in the center of the image. ), 1987, Glossary of Geology. Near the footprint in the above picture, you can see many small "pock-marks." These marks are the craters made by microscopic particles that hit the surface moving at speeds of several kilometers per second. The crater was created instantly when a 50m, 150,000-ton meteor slammed into the desert about 50,000 years ago. by lava flows that obscured the older craters. Ds8d9B nNPS,*_y\v`/>wou__]ewPcLkUU$~z-S|lj O/#lr 9]_nc5u$9a4GVKwsaG|4ot6%?F3Xa:K1r=1\Sw Partner, Earth and Space Science News for Educators. -+eh5 L*]>;ppq Gneissic banding is the easiest of the foliations to recognize. Correspondingly, a zone of rock melt follows the vaporized zone, and when shock energy is further lowered rocks will only be heavily damaged (fractured, brecciated) with decreasing intensity. Fig. At that time, however, the physics of impact cratering implying shock physics was not yet understood. 8. Therefore, a simplified system is used based on texture and composition. ExDsD ;;8-E:(] The same geologic processes that shape Earth, i.e., erosion, impact cratering, tectonism, and volcanism, have left their mark on Mars. 7 0 obj Although impacts of extraterrestrial objects onto the Earth's surface occur at hypervelocity (high speed) and involve much more kinetic energy than any impacts in a classroom lab might do, such a lab can be worthwhile. Justify your answer. Fig. endobj The three stages of impact crater formation. The force can catapult chunks of molten and solid rock hundreds of miles from the impact site this material is known as ejecta flow. The same chemical composition, but two different crystalline structures - therefore, two different minerals. Code of Conduct Fragments of the Canyon Diablo meteorite were found inside the crater. Metaconglomerate is composed of pebbles and gravel that have been flattened due to directed pressure. Dark colors, such as black and dark brown, indicate a mafic or ultramafic composition. It has a raised rim around the edge, and nice, sharp features. Check Pages 101-150 of Planetary_Geology in the flip PDF version. 18. It has some of the clearest water in the world, and the bottom lies nearly 2,000 feet below the surface, making it the deepest lake in the United States.You can gaze down on it from lookouts along the Rim Drive, part of the 500-mile-long Volcanic Legacy Scenic Byway.Or you can peer into its depths during a boat tour to Wizard Island (formed by a more . <> A projectile (like the small plastic sphere) produced the crater in a laboratory hypervelocity impact experiment. In what direction did the water flow? Computations suggest craters that were formed by a low-density projectile are flatter and have distinctly larger diameter ratios (compared to the above-mentioned one-to-ten ratio of projectile and crater diameter). 12. What are the different kinds of craters? However, this is not a sensible practice in a large lab with many different people handling the samples. Moreover, the principles of superposition and cross-cutting relations indicate that a feature which at least partly covers another feature is the younger. Students, staff, and faculty at Stony Brook University are hard at work gathering data on the history of Mars. 13) hits the earth? Volcanism has produced vast lava flows, broad shield volcanoes, and plains of volcanic material. Sand is clasts between 1/16 and 2 mm in size, and gravel is greater than 2 mm. Sediment is deposited in a number of environments of deposition, by both moving air and moving water. Fig. What process do you think formed Reuyl crater (marked B on Figure 11.5)? This especially concerned also the vaporization of the impactor by shock-induced temperatures and, at that time, let the mining engineers helpless when they did not encounter the expected 50 m-diameter iron meteorite beneath the floor of the Barringer (Meteorite) crater. You will have to calculate an approximate image scale from the height of the peak in the foreground.) Similar to some river systems on Earth, these Martian channels have a branching pattern. Which is larger, and by how much? Meteor Crater formed only 50,000 years ago. <> Mercury has lots of craters, yet Venus has very few craters, due to its dense atmosphere (containing lots of 'heavy' gases), meaning that many meteorites burn up due to friction in the . 23. % Ma'adim Vallis (labeled C) is the channel in the southeastern part of the image. Source: Google Earth. Ma'adim Vallis is the channel in the southeast part of the photograph, marked C. Which of the four processes do you think formed Ma'adim Vallis? Quartzite is composed of quartz sand grains. The faster the incoming impactor, the larger the crater. Aphanitic texture is a fine grained texture but the crystals are too small to see. . Such a high-speed impact produces a crater that is approximately 20 times larger in diameter than the impacting object. NN `GF9A`U l8_g1g}=""Px2q$O@Y8)Oq-9O{2NW?`9:uMuBiO2qd]{%= LX'K Schistose foliation is composed of larger minerals that are visible to the unaided eye. These crater chains are formed when a comet, normally torn apart by tides, has many of its fragments collide into the planet or moon at nearly the same time. Lastly, pyroclastic texture is composed of volcanic fragments. Which of the four geologic processes might be responsible for the formation of Ius Chasma? * Definitions simplified or modified from Bates, R.L. This impact is thought to have triggered fires and tsunamis and created a cloud of dust and water vapor that enveloped the globe in a matter of days, resulting in fluctuating global climate changes. : Cf Cf @U ' 8 L D # 8 ^ r ( u u u # # # # # # # $ $ r' -# u u -# B# u" u" u" # u" # u" u" w" " pW 0 {" " X# 0 # " ( ( " ( " l u Z @ u" 4 C l u u u -# -# ! Image credit: NASA. !dKG>$D1vAn Ey kde/5RehK;(V+SP;6$:wr7s]0 qh@3rFWTkiuZuC1:e`Di*{"Ge[mIGl e `GRqu]MVte4O.)XPN!QgL!eQ!7*hM,5n7OS@yoY.B>f6>x>/RNR84l,Q/b&^RA,`?l'&)sH,s@+xL:|F+08l7lF4)2BYcJOo!!g3+Ct B |2x G.eG 6`:qTC+K\dI,h^&Q!dZ 7b1UxrxU_60cPYTPOX4RExd-w9+ X'SdFht'~Y=3sQf>\B5y[s{pq],1lbl>{|>?wDxLK#2'UF*$QtiQV9C9MBfKQGR"'#6x T^!mx{8w'IN^p_R ,0IRf2/k-l^cX;;uD+ in Reuyl crater located along the dichotomy boundary (west of Apollinaris Mons ). The result is a "bubbly" appearance. Space shuttle image STS51I-33-56AA, courtesy of the Lunar and Planetary Institute. All four geologic processes can act to shape a planetary landscape. Scratch the unknown mineral with a known hardness to determine which mineral is harder. Larger, more forceful impact events will form complex craters in which the rock at the center of the crater rebounds from the downward pressure of the shock wave and uplifts into a mound-like formation. What happens when an impactor hits? Elastic rebound and collapse cause the excavation trajectories to go into reverse in a way, and the rock masses tend to move upwards and centripetally thus, accompanied by large-scale downfaulting, largely backfilling the transient crater. What geologic process do you think formed Reuyl (labeled B)? HYPERLINK "../Honors227/Images/10_5.jpg"Figure 5. Tswaing Crater. Heavy elements began sinking past the oceans and magma toward the center of the planet. endobj Scientists record the size and number of impact craters and how eroded they are to determine the ages and histories of different planetary surfaces. As a result, there are only around 160 known impact craters in existence today (though there are surely more that havent been discovered). Lake Toba in Sumatra, the largest volcanic structure on Earth, is an example of an enormous caldera that has filled with water over time. . On propagating roughly hemispherically into the underground target rocks, shock wave energy diminishes and so does pressure and temperature. Different crystalline structures, or how the atoms and molecules are arranged, result in different minerals. Smaller planets have less gravitational "pull" than large planets; impactors will strike at lower speeds. 6. Media Policy This will result in the formation of central uplifts and ring systems, and we may now refer to these as central-uplift or central-peak craters, peak-ring craters or multi-ring craters establishing the group of so-called complex impact craters or complex impact structures (Fig. endobj 11. Unlike the rock-into-mud cratering, the excavation in impact cratering is inextricably linked with the propagation of shock waves. And so far, the crater formation process has only lasted a few seconds. Foliated textures show four types of foliation. Suggest some ways in which the scarp around Olympus Mons might have formed. JI,ZbXr}n9=^,eIgtU_=F#-K}_^(qyk1bZe|}elK)&Hc:GVtOd~Y@0IA$2i hvF~/_?g@-)(|#)s5.eK%x]G4;kY|^B8I(JY4+Tl7l1Q)>.ux92BfiYnWy%:./#5*j?hv`SEzY8D7\I&RdEO)I[G*ZGy7HjkvKXE@tiYrG:f3' uoiTK"EF]d[59qqgrP~ "UJ|gmPBO(+aS7Gj{k}xeET]A EIx-X]28dy,}Isx.cepq 7rbr:^v4>iHJgEqA&`DA.FYle1}7#W;G-+h Justify your answer. Coquina is composed almost entirely of shell or fossil fragments. The Moon does not. This portion of the Moon is covered by numerous circular holes. We see that shock wave and rarefaction wave propagation are essential in the formation of a meteorite impact crater. endobj Therefore, older surfaces have more impact craters. endobj Planetary scientists have established from lunar samples returned by Apollo missions that the rate of large asteroid impacts on the Moon was very high after the Moon formed 4.5 billion years ago and then declined rapidly between 3.8 billion and 3.5 billion years ago. The texture of an igneous rock does not refer to the roughness or smoothness of the surface. Planetary_Geology was published by lavit shetty on 2021-11-18. Why does the Moon have so many craters while Earth has so few? The darker material is quartz sand, combined with a small amount of cornmeal to produce a minor amount of cohesion between sand grains. This of course is primarily a matter of energy related with the projectiles mass (and therefore density) and impact velocity, and, subordinately, also a matter of the target lithology. T U ; = B } ~ x z h_X B* CJ ph h_X B* ph Arid climate and a lack of vegetation in the vicinity of Meteor Crater make it an excellent comparison site for similar-sized impact craters on Mars, Ramsey said. If the crater turns out to be gravity-dominated, this lends evidence to the theory that the comet's nucleus consists of porous, pristine, unprocessed material, and that the comet formed . Most obsidian is felsic in composition, yet typically it will have a very dark color (dark brown to black). 20. Texture will still be used but in a different sense than for igneous rocks. However, there are exceptions. 3 strongly resemble meteorite impact craters exhibiting a central uplift like the Tycho impact crater on Earths moon (Fig. In this way, all rock particles behind the expanding shock front are captured by both the compressive shock and the tensile rarefaction, and both combine into a vector of acceleration. Some water probably seeped into the ground and is frozen there today as ice, and some likely escaped into space over time. Justify your answer. Determine and record the diameter of Apollinaris Patera? 18. 4). What process do you think formed Apollinaris Patera? Texture of sedimentary rocks in this lab will be taken to indicate origin or type of sediment found in the rock. What is the texture of the ejecta flow labeled A? You can help Wikipedia by expanding it. | Gosses Bluff (Tnorala) Pingualuit Crater. More about these experiments can be read on the Chiemgau impact website where a hypervelocity impact video may be downloaded. For instance, the famous Chicxulub crater in Yucatan, Mexico, is thought to be the site of the meteor impact that instigated the K-T event, which wiped out the dinosaurs in a mass extinction that affected much of life on Earth. As on the Moon, Mercury, Venus, and most of the outer planet satellites, impact craters are found on the surface of Mars. Look for areas where the light reflects from planar surfaces. 17. (Hint: the region slopes to the north.) a depression formed by an impact (as of a meteorite). Craters produced by the collision of a meteorite with the Earth (or another planet or moon) are called impact craters. Download Citation | On Jan 1, 2014, Teasel Muir-Harmony published Reuyl, Dirk | Find, read and cite all the research you need on ResearchGate. Astronomy Gift Shop: http://www.astronomydvd.com/shop.aspx How were the Moon's craters and maria formed? Around its base is a steep cliff as high as 6 km. Large impact basins are also found on other planets, including Mars and Mercury. Such outbursts can be violent enough that once the eruption is . The Vredefort impact crater, about 100 kilometers (60 miles) from Johannesburg, South Africa, was formed just a little over 2 billion years ago. Determine and record the diameter of the caldera structure (include the over all caldera structure in this measurement). Phaneritic texture is composed of crystals that are large enough to see but smaller than pegmatitic texture, and the entire rock is composed of crystals. Once these two characteristics have been identified, the Igneous Rock Identification chart can be used to help identify the rock name. Essentially, the minerals are randomly oriented. A mystery concerning water on Mars is "Where did it go?" The meter scale indicates water depth. (not recommended in an introductory lab - you don't know who has handled or licked the sample before you).Other PropertiesFluorescence, RadioactivityRequires special equipment such as a UV lamp and geiger counter. Venus has fewer craters; its surface has been covered recently (in the last 500 million years!) Material Type: Lab; Class: Sci Thought/Processes I; Subject: Honors Program; University: George Mason University; Term: Unknown 1989; (Viking MDIM Volume 4) 15. 19.) 8. Image from the Viking Orbiter, courtesy of the Lunar and Planetary Institute. For the following, you will use the knowledge from previous questions to identify Martian landforms and describe the geologic processes that created them. More about the doublet crater. Typically bowl-shaped craters. Since tectonic plate movements has erased much of Earths crater record, the answers to the lingering questions about crater formation and timelines lie in the exquisitely preserved craters on the moon. We can also see an inverted channel system, possibly ponded toward the southwest. Erosion is the dominant geologic process acting on Mars today. 10 0 obj Reuyl crater is at the southern edge of a region known to be blanketed in thick dust based on its high albedo (brightness) and low thermal inertia values. Marble is composed of calcite and will readily react to a small drop of HCl. | "Gazetteer of Planetary Nomenclature | Reuyl", https://en.wikipedia.org/w/index.php?title=Reuyl_(crater)&oldid=998864518, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 7 January 2021, at 10:50. Below you will find a chart which defines the physical properties and provides the means for determining the physical property of a mineral sample. Image credit: NASA. A central-uplift (central peak) crater (Gow, Canada, 4 km diameter). Although temperatures below freezing and low atmospheric pressures do not allow liquid water on the surface of Mars today, erosion processes involving running water were important on Mars in the past. This article about an extraterrestrial geological feature is a stub. Albite and anorthite are two examples. The curious central mound within the craters can be explained by Hertzian and spallation fracturing on collision with the hard hailstones. Where were really going to get the answers the gold standards of answers is when we go back to the moon, Kring said. Complex craters are large craters with complicated features. What are craters? Southern cratered highlands. Statistically, impact trajectories most abundantly form an oblique 45 angle with the target surface. The bottom line is, everything that happened on the moon happened on the Earth, said David Kring, crater expert and team leader for Center for Lunar Science and Exploration. January 2014; <> 15. Craters come in two flavors: those that aren't caused by asteroids or comets, impact craters, are formed by powerful volcanic explosions.
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