Justify your answer. stream
), 1987, Glossary of Geology. Clay and silt are less than 1/256 mm. 03.04.10. Early in the formation of the solar system, frequent and large impacts were common for all of the planets and moons. The moons surface is riddled with craters ranging in size and structural complexity, and billions of years ago before life emerged, the Earth looked the same way. Then, elongated craters may be formed, and the ejecta blanket may considerably deviate from a circular symmetry. Fig. Statistically, impact trajectories most abundantly form an oblique 45 angle with the target surface. Transcript (121 KB) Overview : Impact cratering is, arguably, the most important and fundamental geological process in the Solar System. First, the impactor rushes toward the surface. * Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project 13) hits the earth? Fig. A very rough rule of thumb amounts to the order of a one-to-ten diameter ratio. Platy minerals tend to dominate. (Viking MDIM Volume 4)
15. 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. The prevailing theory supported by the scientific community, the giant impact hypothesis suggests that the moon formed when an object smashed into early Earth. Explain your answer. Albite and anorthite are two examples. Earth continues to be a target and contrary to popular opinion, the Moon does not act as a meteoroid deflector (it is too small and too distant!). 64 0 obj
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Most obsidian is felsic in composition, yet typically it will have a very dark color (dark brown to black). <>
How many objects from space impact Earth each year? Wow, that's massive. (Viking MDIM Volume 4)
13. Obsidian is volcanic glass which erupts as a lava flow. 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. Impact shock waves are characterized by an instantaneous onset of extreme pressures (up to the order of megabars) and extreme temperatures (up to 10,000 degrees or more) on release of the pressure. 2 0 obj
Color is often an indicator of the composition of a rock or mineral and can be effectively used to identify the composition of most igneous rocks. 20. How the atoms and molecules are arranged and the strength of the bonding between the atoms result in different physical properties for different minerals. The first reason is that Earth's surface is continuously changing because we live on a geologically active planet. The rock is composed entirely of glass. Light colors, including white, light gray, tan and pink, indicate a felsic composition. Fig. 288 pp, The University of Arizona Press, Tucson, 1986. As a result, there are only around 160 known impact craters in existence today (though there are surely more that haven't been discovered). The Crater Maker should stand over their sand-filled container and hold their arm out at the height they are going to drop it. Free essays, homework help, flashcards, research papers, book reports, term papers, history, science, politics These fragments or clasts can be very fine (ash) or coarse (lapilli) or very coarse (bombs and blocks). * Definitions simplified or modified from Bates, R.L. 1). - Lunar and Planetary Institute It is located along the north border of the Snake River Plain in Idaho. endobj
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Tycho meteorite crater on the Moon. Typically the large crystals (phenocrysts) are visible while the smaller crystal are not (referred to as groundmass). Aphanitic texture is a fine grained texture but the crystals are too small to see. And so far, the crater formation process has only lasted a few seconds. Very similar, but still different, therefore two different minerals. Google Earth image. These craters are, however, decidedly not impact structures. A complex crater in the northern region of Mars. The image shows ring-like structures that extend to about 280 kilometers (175 miles) from the center. The greater the mass of the impactor, the greater the size of crater. Keep track of the craters you measured. The force of the impacts create circular structures with raised rimmed wall; spatters of mud and smaller circular secondary craters may be seen (Fig. Igneous Rock Identification ChartCOMPOSITION
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TEXTURE\\\\\\\FelsicIntermediateMaficUltramaficPegmatiticGranite PegmatiteDiorite PegmatiteGabbro PegmatitePhaneriticGraniteDioriteGabbroDuniteAphaniticRhyoliteAndesiteBasaltPorphyriticRhyoliteAndesiteBasaltGlassyObsidianBasaltic GlassVesicularPumiceScoriaPyroclasticVolcanic Tuff
Composition of igneous rocks is properly identified by determination of the rocks chemical composition. d. Maadim Vallis is the channel in the southeast part of the photograph, marked C. Which of the four processes do you think formed Maadim Vallis? Essentially, the minerals are randomly oriented. The high-speed impact of a large meteorite compresses, or forces downward, a . Around its base is a steep cliff as high as 6 km. 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 . Consider the relationship between Ma'adim Vallis and Gusev, the 160 km diameter . | Chemical sedimentary rocks are identified by identifying the mineral from which they are composed. The dark brown to black color is the most obvious characteristic. by lava flows that obscured the older craters. The GIF below shows the formation sequence of the model (a YouTube . Consider the relationship between Ma'adim Vallis and Gusev, the 160 km . The transition from simple to complex craters occurs at about 1.5 to 4 km (depending on the target rocks) final diameter for terrestrial craters and is much larger (c. 15 km) for craters on the Moon. But Earth has several things the moon doesnt an atmosphere and liquid water that cause erosion. Schistose foliation is composed of larger minerals that are visible to the unaided eye. xZms|fl d;NrHIM. (a) Geomorphic map of Reuyl crater. In fact, the differences between craters provide a lot of information about how the craters formed, when they formed, and why. Foliated textures show four types of foliation. This portion of the Moon is covered by numerous circular holes. Halite has a hardness of 2.5 and cannot be scratched by a fingernail (unpolished fingernail). Download Planetary_Geology PDF for free. HYPERLINK "../Honors227/Images/10_4.jpg"Figure 4. 19). Such a high-speed impact produces a crater that is approximately 20 times larger in diameter than the impacting object. What are the different kinds of craters? Felsic compositions are rich in silica (SiO2). | Procedures and Questions: Part 3
Now we examine some Valleys west of Chryse Planitia. Sinuous Ridge Materials in Reuyl Crater. Fig. Dark colors, such as black and dark brown, indicate a mafic or ultramafic composition. It was declared a national monument by President Calvin Coolidge in 1924. More about the doublet crater. It is colder inside some craters near the lunar poles than it is on the surface of Pluto (25K, or -415F). Source: Google Earth. Topography from echo sounder measurements. Dual crater at the bottom of Lake Chiemsee, Bavaria (Germany) that very probably formed in the large Holocene Chiemgau impact event. Computer simulations show that the modification process may already begin before standstill of the excavation leading to large-scale countermovement of rock masses. %PDF-1.4
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Complex craters are large craters with complicated features. endobj
Which of the four geologic processes might be responsible for the formation of Ius Chasma? 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. 14. Using the following picture
draw a box around the area that is shown in Figure 2. Clastic sedimentary rocks contain clasts. xTO@~^^g!$(01D=l{t endobj
The white material comprising the central peak is glass microbeads. [Hint: use the principle of cross-cutting relations to justify your answer.] 5 0 obj
Image credit: NASA. Explain their similarities and their differences. These temperatures are enough to more or less completely vaporize the impactor and a volume of the target rocks roughly comparable to the volume of the impactor, resulting in a giant expanding impact vapor plume. )y&bS_jW+|z6ADS FZM+q&+rVim#yHNO 8tU#T.f-[`of=XzuEvr+Ll[fXt
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UGs@wc This suggests that the transient crater collapse in the modification stage is largely driven by gravity (gMoon ~ 1/6 gEarth). Craters most often are circular. A projectile (like the small plastic sphere) produced the crater in a laboratory hypervelocity impact experiment. Vesicular texture is formed when lava solidifies before gases are able to escape. The insets in the black boxes show close-ups of some of the structures that lava can form: (left) branched channels, (middle) a snaking channel and (right) rootless vents; the rootless vents are also marked by yellow spots on the main image. (Hint: remember that wind direction refers to the direction from which the wind blows.) %
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. Meteor Crater is 1.2km wide and 175m deep. The more mass it has the bigger the impact. Terraces are a common feature of many large craters---for another example, look at the crater Theophilus. Halite is common table salt and is most easily identified by taste. While many minerals share common physical properties, when all of a mineral's physical properties are examined, it often results in a unique set of physical properties which can be used to identify the mineral. 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]. Earth has weather, water, and plants. 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. Smaller valleys join the main east-west chasm. As on the Moon, Mercury, Venus, and most of the outer planet satellites, impact craters are found on the surface of Mars. Justify your answer. Consult your lab manual for detailed discussion. At that time, however, the physics of impact cratering implying shock physics was not yet understood. Sometimes the force of the impact is great enough to melt some of the local rock. Tenoumer Crater. Different crystalline structures, or how the atoms and molecules are arranged, result in different minerals. Cross sections of simple and complex impact craters. Moreover, the polar caps contain some water ice. From the geological map (Tanaka et al., 2014) it is evident that Reuyl crater formed over a Noachian-Hesperian dichotomy boundary surface. 13. Tychos diameter is 85 km. <>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 17 0 R/Group<>/Tabs/S/StructParents 1>>
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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. 5. The compression stage of crater formation involves that initial exchange of energy between the projectile and the impact area. Partner, Earth and Space Science News for Educators. As a result, there are only around 160 known impact craters in existence today (though there are surely more that havent been discovered). Southern cratered highlands. These are not commonly tested for in an introductory lab. As a rule of thumb, older surfaces have been exposed to impacting bodies (meteoroids, asteroids, and comets) for a longer period of time than younger surfaces. (Viking MDIM mosaic 211-5360)
1. Study with Quizlet and memorize flashcards containing terms like Where do you find the thickest ejecta?, How do you think the crater rim formed?, Where would you find most of the younger material? Determine and record the diameter of the caldera structure (include the over all caldera structure in this measurement). endobj
The two most notable are obsidian and dunite. The so-called Meteor Crater in Arizona previously held the record for largest impact crater less than 100,000 years old; it's about 49,000 to 50,000 years old and measures 0.75 miles (1.2 km) in . Therefore, a simplified system is used based on texture and composition. Although craters look like imprints of a giant fist smashing the ground inward, impact shock waves have the opposite effect, which planetary scientists divide into three phases. But no matter at what angle it makes contact, the enormous amount of kinetic energy the projectile carries immediately transfers to the target rock it hits, triggering powerful shock waves. Rich in silica ( SiO2 ) texture is formed when lava solidifies before gases are able to escape are... 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