Justify your answer. Larger impacts also still occur, but these are much more rare. Heavy elements began sinking past the oceans and magma toward the center of the planet. Which of the four geologic processes might be responsible for the formation of Ius Chasma? Dunite has an ultramafic composition yet is apple green to yellowish green in color. More about these experiments can be read on the Chiemgau impact website where a hypervelocity impact video may be downloaded. Copernicus is a large crater (93 kilometers or 60 miles wide) on the Moon. 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. 7. This planar character can be flat like a piece of slate or folded. The twoprojectile produced a pair of rimmed simple, bowl-shaped craters quite similar to the dual craters from Fig. Thank you for your participation! Using the following picture draw a box around the area that is shown in Figure 2. Free essays, homework help, flashcards, research papers, book reports, term papers, history, science, politics Metamorphic Rock Identification ChartTEXTUREFOLIATIONCOMPOSITIONTYPEPARENT ROCKROCK NAMEFoliatedslatymicaRegionalMudstoneSlatephylliticquartz, mica, chloriteRegionalMudstonePhylliteschistosemica, quartzRegionalSlateSchistschistoseamphibole, plagioclaseRegionalBasalt or GabbroAmphibolitegneissic bandingfeldspar, mica, quartzRegionalSchistGneissNon-FoliatedcarbonContact or RegionalBituminous CoalAnthracite Coalquartz, rock fragmentsContact or RegionalConglomerateMetaconglomeratecalciteContact or RegionalLimestoneMarblequartzContact or RegionalSandstoneQuartzite Mars Surface Introduction In many ways Mars is similar to Earth. Hailstone craters. 19. Compare Apollinaris Patera (marked A on Figure 5) to Olympus Mons (Figure 1). The diameter of the each miniature craters is 5 10 mm. <> Its features, such as the ejecta blanket beyond its rim, are well preserved because of the crater's youth; it has not experienced extensive erosion. This article about an extraterrestrial geological feature is a stub. Thus, if a valley cuts through a crater, the crater must be older. 18. Texture is divided into two groups. Ds8d9B nNPS,*_y\v`/>wou__]ewPcLkUU$~z-S|lj O/#lr 9]_nc5u$9a4GVKwsaG|4ot6%?F3Xa:K1r=1\Sw <> For the roughly 200 established terrestrial impact structures neither a comet nor a rubble pile asteroid could definitely be shown to have been the impactor. Image credit: NASA. What are the different kinds of craters? 14. You will have to calculate an approximate image scale from the height of the peak in the foreground.) 19.) More elongate craters can be produced if an impactor strikes the surface at a very low angle less than 20 degrees. Inclusion, Diversity, Equity & Accessibility (IDEA). by lava flows that obscured the older craters. The reflected tensile stresses are insofar crucial as the tensile strength of rocks is much lower than the compressive strength. Fortunately determination of the exact chemical composition is not necessary. endobj Gypsum is relatively soft (Hardness =2) and can be scratched easily with a fingernail. Moon craters are formed by volcanism and cratering. 4) What process do you think formed Apollinaris Patera, marked A? The high-speed impact of a large meteorite compresses, or forces downward, a . T U ; = B } ~ x z h_X B* CJ ph h_X B* ph Sediment is deposited in a number of environments of deposition, by both moving air and moving water. The faster the incoming impactor, the larger the crater. <> ), 1987, Glossary of Geology. rBqf]&&3|sz!g8zGci3;U%SK@~hvOg[-=A'c'Z/m~V;;Y=7V99Z}kc|O;7'1m C73C?$so/Exa2Eiu8*B,Xh${BN` d&;W;D[-"Ost"/#6N*(#wz]GU How big, e.g. 9). Apart from the distinct role rarefactions waves play in the formation of the excavation flow field, they are especially relevant geologically. There are some interesting erosional signs in this observation, which will make for a good comparison with other intracrater fans and fluvial sedimentary landforms. endobj And the trump card, plate tectonics, that recycles much of the planets crust over millions of years and smooths away blemishes left by cosmic impacts. <> This "period of heavy bombardment" ended by about 3.9 billion years ago. The polar caps shrink during local summer and grow during local winter. It has a summit caldera some 80 km wide. 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. A crater is a bowl-shaped depression, or hollowed-out area, produced by the impact of a meteorite, volcanic activity, or an explosion. Tenoumer Crater. 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? and J.A. A complex crater in the northern region of Mars. On Mars, meteor storms 100 million years ago may have literally shaken the Red Planet to the core and destroyed its magnetic field. in Reuyl crater located along the dichotomy boundary (west of Apollinaris Mons ). 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. What process do you think formed Apollinaris Patera? 23. Ma'adim Vallis (labeled C) is the channel in the southeastern part of the image. 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. Textures are based primarily on crystal size. Justify your answer. (Viking MDIM Volume 4) 15. 2) we may think it somehow formed from an identical mechanism. Fragments of the Canyon Diablo meteorite were found inside the crater. 14 0 obj Fig. The size and shape of the crater and the amount of material excavated depends on factors such as the velocity and mass of the impacting body and the geology of the surface. Such outbursts can be violent enough that once the eruption is . Halite is common table salt and is most easily identified by taste. Beware that even though an igneous rock may have a felsic composition (light color), the rock can contain dark colored minerals. 18. 245 pp, Oxford Univ. <> 14. 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. 7. <> 6). Three processes help Earth keep its surface crater free. The Measurer should measure from the ground to how high the rock is, and ask the Recorder to write down that height under the heading "Meteor 1, Trial 1". Biologic sedimentary rocks are which form as the result of the accumulation of organic material or biologic activity. The more mass it has the bigger the impact. The edges of these larger craters also may slump, creating terraces that step down into the crater. The origins of Uluru (and Kata Tjuta) date back about 500 million years, to around the same time the Australian continent was formed. Procedures and Questions: Part 4 The Hesperia region in the southern hemisphere consists of cratered plains which have been modified by aeolian processes. 13 0 obj Felsic compositions are rich in silica (SiO2). Peak ring crater Rachmaninoff on Mercury. 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. It has a raised rim around the edge, and nice, sharp features. Aphanitic texture is a fine grained texture but the crystals are too small to see. The extreme environmental shifts caused a mass extinction of 75% of Earth's species, including the dinosaurs. Fig. 13. Procedures and Questions: Part 2 Ius Chasma is part of the western end of Valles Marineris, the largest Martian canyon. Shock waves behave like other waves: they can interfere and they may be reflected and refracted. This crater is believed to have formed when an asteroid struck Earth 65 million years ago. Fig. 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). (Viking MDIM Volume 4) 13. The somewhat blurred contours are not surprising giventhe impact happened into water and a soft, water-saturated target rock. 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. Chemical sedimentary rocks are identified by identifying the mineral from which they are composed. Computing these vectors (direction and magnitude) for each point in the subsurface, a field of excavation flow with arcuate trajectories as shown in the sketch above (Fig. The meter scale indicates water depth. Planet Earth holds some of the strangest, natural tourist . In the following, these three stages are illustrated and described in a somewhat simplified manner. Unlike the rock-into-mud cratering, the excavation in impact cratering is inextricably linked with the propagation of shock waves. eige6 When an asteroidal or cometary object strikes a planetary surface, it is traveling typically at several tens of kilometres per secondmany times the speed of sound.A collision at such extreme speeds is called a hypervelocity impact. Foliated textures show a distinct planar character. This portion of the Moon is covered by numerous circular holes. Go to Analyze-Label Selection, and the crater line you just . Topography from echo sounder measurements. Both are black in color, and is composed of carbon. Earth and the other planets are constantly bombarded by tiny debris from space, much of which burns up in the atmosphere. The Vredefort impact crater, about 100 kilometers (60 miles) from Johannesburg, South Africa, was formed just a little over 2 billion years ago. 3. How can craters be used to determine the age of a planet or moon? 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. This can be easily confused with a crystal face and is the most difficult properties for students to master.ColorVisible light spectrum radiation reflected from a mineral.Look at the sample and determine its color - white, black, green, clear, etc.Crystal FormGeometric shape of a crystal or mineral.Examine and describe the geometric shape of the mineral - cubic, hexagonal, etc. Degraded craters -- Craters that have become eroded due to weathering, lava flows, impacting, or downslope movement of material. 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. Scratch the unknown mineral with a known hardness to determine which mineral is harder. 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. Mafic rocks may contain light colored minerals as well. 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]. endobj Check Pages 101-150 of Planetary_Geology in the flip PDF version. The number of very large craters in the southern highlands implies a substantial age for the surface. 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. Three types of sedimentary rock "texture" are clastic, chemical, and biologic. Clastic sedimentary rocks contain clasts. A good example is diamond and graphite. The first reason is that Earth's surface is continuously changing because we live on a geologically active planet. 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. Albite and anorthite are two examples. Sometimes lots of particles strike at one time, creating meteor showers. (b) Contour map derived from the MOLA 463m/pixel DTM, with the . Few, if any, crystals will be visible. The crater has been extensively eroded, but is believed to originally have been as much as 300 kilometers (185 miles) across. The model crater developed a nice central peak as well as terraced margins. Nrdlinger Ries. HYPERLINK "../Honors227/Images/10_5.jpg"Figure 5. Justify your answer. Measure and record the width of the Ius Chasma. 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 same chemical composition, but two different crystalline structures - therefore, two different minerals. Location: 24S, 245W. 20. What process do you think formed Reuyl crater (marked B on Figure 11)? xZms|fl d;NrHIM. The shock wave fractures the rock and excavates a large cavity (much larger than the impactor). I noticed the young crater has an odd shape, non-circular, almost diamond-shaped. 21. 18. Impact craters are relatively shallow, so these "dents" in Earth's rocky . Gosses Bluff (Tnorala) Pingualuit Crater. However, this is not a sensible practice in a large lab with many different people handling the samples. Smaller valleys join the main east-west chasm. The dark basins can be seen by the naked eye. Fig. endstream These are not commonly tested for in an introductory lab. As lower levels of the lava start to cool, they are also pulled . These definitions and methods are simplified. 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. Valley systems cut through many of the cratered terrains of Mars and have characteristics analogous to water-cut valleys on Earth. 5. A peak ring crater (Clearwater West, Canada, 32 km diameter). 6 0 obj Justify your answer. The crater retention age on the ejecta of the unnamed crater is 3.7 Ga which suggests that the crater likely formed during the Noachian-Hesperian period boundary or earlier. Context Image. Calcite readily reacts with a small drop of HCl. Procedures and Questions: Part 5 Finally, let's examine Apollinaris Patera and surrounding region. It is the oldest and largest impact crater recognized on Earth's surface. 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