This image shows the variations in the gravity field near the buried impact crater. b.The process that I think formed apollinaris patera is Volcanism, this is because of its characteristics, such as the radial flow patterns, and basal scarp, a craters, large flow trending to the south, and the less complex caldera.. c.The process that I think formed Reuyl crater, is an Impact, the reason for this is by the ejecta pattern and central peak. Measure and record the east-west and north-south diameters. What process do you think formed Apollinaris Patera? The image to the left is a very simple, bowl shaped crater on the Moon and is typical of small craters that have formed relatively recently. What process do you think formed Reuyl crater (marked B on Figure 11.5)? A central-uplift (central peak) crater (Gow, Canada, 4 km diameter). 12 0 obj The cratering process will help reveal what type of material makes up the nucleus (or at least the outer layer), and therefore how the comet formed and evolved. Inclusion, Diversity, Equity & Accessibility (IDEA). This means that our own planet is one of the youngest in the Solar System. Different crystalline structures, or how the atoms and molecules are arranged, result in different minerals. The largest impact basin on the Moon is 2500 kilometers (1550 miles) in diameter and more than 12 kilometers (7 miles) deep. The crater has been extensively eroded, but is believed to originally have been as much as 300 kilometers (185 miles) across. !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+ 6 0 obj These are not commonly tested for in an introductory lab. The larger size gives the foliation a slighly shiny appearance. In the case of small transient craters, modifications are moderate. Phyllitic foliation is composed of platy minerals that are slightly larger than those found in slaty cleavage, but generally are still too small to see with the unaided eye. On relieving of pressure, there is an elastic rebound at the crater floor now hosting a layer of brecciated rocks. 7. 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. Here again, the difference is obvious: In the case of cobble-into-mud or raindrop impacts the craters are not much larger than the projectile (Fig. Determine and record the diameter of the caldera structure (include the over all caldera structure in this measurement). Justify your answer? endobj Although the resulting depression may bear some resemblance to the hole that results from throwing a pebble into a sandbox, the . Individual craters are degraded or destroyed over time by erosional processes and further cratering. 14. Calcite readily reacts with a small drop of HCl. This planar character can be flat like a piece of slate or folded. Fig. Photo Policy Halite has a hardness of 2.5 and cannot be scratched by a fingernail (unpolished fingernail). Sedimentary rock identification is primarily based on composition. Image credit: NASA. Moreover, the principles of superposition and cross-cutting relations indicate that a feature which at least partly covers another feature is the younger. Before focusing on this important question, we have first to clarify the meaning of the term meteorite impact crater or impact structure. This image shows a simple crater on Mars that has no central peak or terraces around its edges. The three stages of impact crater formation. Craters can be used to determine the relative ages of Martian surface materials; in general, older surfaces have craters which are more numerous, larger, and more degraded than those on young surfaces. Name _____ COSMORPHOLOGY - May 2009 Geologic landforms Purpose: By studying aerial photographs you will learn to identify different kinds of geologic features based on their different morphologies and learn the processes involved in their formation. Explain your answer. Larger craters can have terraces, central peaks, and multiple rings. Beware that even though an igneous rock may have a felsic composition (light color), the rock can contain dark colored minerals. (a) Geomorphic map of Reuyl crater. Peak ring crater Rachmaninoff on Mercury. How many objects from space impact Earth each year? 17 0 obj Halite is common table salt and is most easily identified by taste. During the excavation phase, the massive shock wave causes the projectile to simultaneously melt and vaporize, spewing plumes of searing hot rock vapor miles high into the atmosphere. This was obviously not the case, and so most of the Moon craters could not be meteoritic. Impact craters are relatively shallow, so these "dents" in Earth's rocky . Study area : Reuyl crater (9.6S, 166.9E) diam e-ter and depth is ~84 km and ~2.6 km respectively (Fig.1 a). Do you think the surface of Olympus Mons is geologically old or young, compared to the surface of the Moon? (b) Contour map derived from the MOLA 463m/pixel DTM, with the . NN `GF9A`U l8_g1g}=""Px2q$O@Y8)Oq-9O{2NW?`9:uMuBiO2qd]{%= LX'K How does the mass of the projectile affect the cratering process? Measure and record the diameter of Olympus Mons. Fortunately, these two aspects determine a mineral's physical properties. must an impactor be to produce a given size impact structure? * Definitions simplified or modified from Bates, R.L. Light colors, including white, light gray, tan and pink, indicate a felsic composition. What is the diameter of the large crater towards the bottom of the image? Clastic sedimentary rocks contain clasts. Scientists estimate that Earth and the other terrestrial planets are struck by, on average, five asteroids less than 2 kilometers (a little over 1 mile) across every million years. 17. The ejecta of the larger crater is different from that of the smaller crater. Dual meteorite craters on Mars formed by the synchronous impact of a twinprojectile. HYPERLINK "../Honors227/Images/10_1.jpg"Figure 1. Therefore, crisp craters with upraised rims and steep sides are young, while less distinct and eroded craters with partial rims are probably older. Non-foliated textures have minerals that are not aligned. Multi-ring basin Mona Lisa on Venus. Enormous collapse calderas are found on the summits of each of the volcanoes. The darker material is quartz sand, combined with a small amount of cornmeal to produce a minor amount of cohesion between sand grains. Sinuous Ridge Materials in Reuyl Crater. Albite and anorthite are two examples. Through a combination of these principles, the relative ages of geologic features can be determined, and a sequence of geologic events developed. Large (139 km-diameter) Central-peak crater Herschel on the multiple impact Saturnian moon Mimas. 11. The polar caps shrink during local summer and grow during local winter. 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. Fig. Lava later flowed across the low floors of the basins, giving them a darker, smoother appearance than the surrounding, brighter highlands. What process do you think formed Reuyl crater (marked B on Figure 11.5)? Image from the Mars Global Surveyor, courtesy of the Lunar and Planetary Institute. 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. Dunite has an ultramafic composition yet is apple green to yellowish green in color. Coquina and limestone are both composed of calcite. The white material comprising the central peak is glass microbeads. 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. There are some interesting erosional signs in this observation, which will make for a good comparison with other intracrater fans and fluvial sedimentary landforms. Explain their similarities and their differences. Intermediate compositions have an intermediate color, often gray or consisting of equal parts of dark and light mineral. What happens to the transient crater? Typically bowl-shaped craters. January 2014; Galileo Image (PIA00405), produced by the United States Geological Survey, courtesy of NASA. Explain why you believe the way you do. 10 0 obj Determination of this information is not easily accomplished in this lab. These craters are, however, decidedly not impact structures. At some time in their life nearly every girl, boy (and adult) has thrown pebbles or cobbles into mud and watched nice round form. 5) Ma'adim Vallis is the channel in the southeast part of the photograph, marked D. What processes do you think formed Ma'adim Vallis? (Hint: remember that wind direction refers to the direction from which the wind blows.) This means that the minerals in the rock are all aligned with each other. Some water probably seeped into the ground and is frozen there today as ice, and some likely escaped into space over time. If an impactor is large enough, some of the material pushed toward the edges of the crater will slump back toward the center and the rock beneath the crater will rebound, or push back up, creating a central peak in the crater. Image courtesy of V. L. Sharpton through the Lunar and Planetary Institute. Fig. 5. The Moon does not. Anthracite coal is similar to bituminous coal. (Viking MDIM mosaic 211-5360) 1. Venus has fewer craters; its surface has been covered recently (in the last 500 million years!) Here is a look at the violent, battered past of the . For the following, you will use the knowledge from previous questions to identify Martian landforms and describe the geologic processes that created them. 9). The term transient crater means the cratering process continues after the excavation flow comes to rest. (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. endstream Thus, if a valley cuts through a crater, the crater must be older. Planet Earth holds some of the strangest, natural tourist . Dark colors, such as black and dark brown, indicate a mafic or ultramafic composition. Different chemical compositions result in different minerals. A stone-into-mud crater demonstrates the difference between it and a hypervelocity crater (Fig. 6) Consider the relationship between Ma'adim Vallis and Gusev, the 160 km diameter crater marked C. Further identification of non-foliated rocks is dependent on the composition of the minerals or components in the rock. Are the craters you observe older or younger than the valleys? Limestone may or may not contain fossils. (Viking MDIM Volume 4) 15. endobj As a result, there are only around 160 known impact craters in existence today (though there are surely more that havent been discovered). 20. However, this is not a sensible practice in a large lab with many different people handling the samples. A mystery concerning water on Mars is "Where did it go?" A peak ring crater (Clearwater West, Canada, 32 km diameter). Valleys on western Chryse Planitia near Viking 1 site. Valley systems cut through many of the cratered terrains of Mars and have characteristics analogous to water-cut valleys on Earth. 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!). Which is larger, and by how much? Pretty much any tiny dent made on the Moon's surface is going to stay there. Part of the ejecta of the larger crater was molten, melted rock and formed flows. Larger impacts also still occur, but these are much more rare. and more. Textures are based primarily on crystal size. 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. Based on your observations, what is the probable order of occurrence of A, B, C, and D in Figure 5 (i.e., which came first, second, third, last)? 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. 1 0 obj Space shuttle image STS51I-33-56AA, courtesy of the Lunar and Planetary Institute. The Vredefort impact crater, about 100 kilometers (60 miles) from Johannesburg, South Africa, was formed just a little over 2 billion years ago. Terraces are a common feature of many large craters---for another example, look at the crater Theophilus. What are some of Earth's famous impact craters? Determination of the actual chemical composition and crytalline structure of a mineral is difficult without the proper equipment. Lake Toba in Sumatra, the largest volcanic structure on Earth, is an example of an enormous caldera that has filled with water over time. Fig. [Hint: use the principle of cross-cutting relations to justify your answer.] 14 0 obj Earth and the other planets are constantly bombarded by tiny debris from space, much of which burns up in the atmosphere. 20. Sometimes the force of the impact is great enough to melt some of the local rock. Most obsidian is felsic in composition, yet typically it will have a very dark color (dark brown to black). How looks an impact crater that was produced by an oblique impact? Source: https://news.discovery.com/earth/how-are-craters-formed.html, Center for Planetary Exploration (CPEx) Opens at Stony Brook University. The force of the impacts create circular structures with raised rimmed wall; spatters of mud and smaller circular secondary craters may be seen (Fig. XX=S;K]3:V-j ,bxHeM?qaZ] R*Jf]x-Tfymoy{!TX&THH9C]NXg 2. oqoujYm<3, \xu_-^/NiU,*&N ]L$[LDf>q@#SB9o9~-EPs lRj{u/wk\:oD $Ly Which of the four geologic processes might be responsible for the formation of Ius Chasma? 1. The GIF below shows the formation sequence of the model (a YouTube . Much of Earth's surface is recycled through plate tectonic activity (and erosion), so Earth also has few craters. Fig. What are craters? Four minerals that need to be identified are quartz, halite, gypsum and calcite. Tychos diameter is 85 km. The contact and compression stage of impact cratering. Fragments of the Canyon Diablo meteorite were found inside the crater. A crater is a bowl-shaped depression, or hollowed-out area, produced by the impact of a meteorite, volcanic activity, or an explosion. Typically, these rocks split along parallel, planar surfaces. 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 greater the mass of the impactor, the greater the size of crater. | ), 1987, Glossary of Geology. <>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 17 0 R/Group<>/Tabs/S/StructParents 1>> Sand and dust particles carried by the wind form dunes and windstreaks. Terms of Use, Copyright document.write(new Date().getFullYear()); Sand is clasts between 1/16 and 2 mm in size, and gravel is greater than 2 mm. Impacts are instantaneous events. The crater is 2 kilometers (about 1 mile) wide. What geologic process do you think formed Reuyl (labeled B)? The result is a "bubbly" appearance. There is no other reasonable explanation for the occurrence of such a peculiar structure at the bottom of the glacial Lake Chiemsee. Southern cratered highlands. The rock is composed entirely of glass. Earth has weather, water, and plants. Compare the size of Ius Chasma and its tributaries to the size of the Grand Canyon of Arizona (approximate length=175 km and maximum width=29km). Go to Analyze-Label Selection, and the crater line you just . Something we dont understand very well on the geological side (of crater formation) is, we still find it difficult to determine the trajectory of impacting objects for most impact craters, Kring said. Chemical sedimentary rocks are identified by identifying the mineral from which they are composed. If the projectile . 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. A complex crater in the northern region of Mars. Ma'adim Vallis (labeled C) is the channel in the southeastern part of the image. Then, elongated craters may be formed, and the ejecta blanket may considerably deviate from a circular symmetry. Meteors incorrectly called shooting stars are the streaks of light created as particles of dust and ice vaporize in our atmosphere. 11. Astronomy Gift Shop: http://www.astronomydvd.com/shop.aspx How were the Moon's craters and maria formed? The large circular dark areas in the image are impact basins, created as huge impactors struck the Moon. Justify your answer. What process do you think formed Reuyl crater (marked B on Figure 5)? Look this information up in your lab manual once the mineral has been identified.StreakColor of the mineral when it is powdered.Grind a small amount of a mineral into a powder on a porcelain streak plate and determine the color of the powder.TasteNerve ending reaction in the tongue to different chemicals.Lick the mineral. For larger transient craters the modifications may take on a dramatic scale. 6). <> Details from the Ascraeus channel (red), meandering across the surface of Mars. -+eh5 L*]>;ppq 3. Such outbursts can be violent enough that once the eruption is . For very large impact craters, the excavation and modification stages are not as discrete as previously written. Hb```,6 u!b`0pT 9, ",8FRc g3g86y~D#*}So ". Download Planetary_Geology PDF for free. It is colder inside some craters near the lunar poles than it is on the surface of Pluto (25K, or -415F).