. Thus, if a valley cuts through a crater, the crater must be older. Determination of this information is not easily accomplished in this lab. Craters are roughly circular, excavated holes made by impact events. Generally speaking, large impact craters appear to be morphologically flat structures although the impact signature rock deformations, shock metamorphism may extend to considerable depths. 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. The now existing bowl-shaped structure surrounded by an uplifted rim and a blanket of ejected material is termed the transient crater obviously indicating a continuation of the impact cratering process arriving in the modification stage. Consider the relationship between Ma'adim Vallis and Gusev, the 160 km . Known as one of the best-preserved impact craters on Earth, it is 180 meters (590 feet) deep and 1.2 kilometers (0.75 miles) in diameter. Tycho meteorite crater on the Moon. The extreme environmental shifts caused a mass extinction of 75% of Earth's species, including the dinosaurs. 12. Anthracite coal is generally shiny in appearance and breaks with a conchoidal fracture (broken glass also shows this type of fracture). 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. The twoprojectile produced a pair of rimmed simple, bowl-shaped craters quite similar to the dual craters from Fig. Procedures and Questions: Part 4 The Hesperia region in the southern hemisphere consists of cratered plains which have been modified by aeolian processes. Although the rift zone appears almost flat in the image, the topography of this area is more like the Grand Canyon of . HYPERLINK "../Honors227/Images/10_3.jpg"Figure 3. 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. There are some interesting erosional signs in this observation, which will make for a good comparison with other intracrater fans and fluvial sedimentary landforms. Before focusing on this important question, we have first to clarify the meaning of the term meteorite impact crater or impact structure. The Crater Maker can then drop the rock, and the Measurer . Then, elongated craters may be formed, and the ejecta blanket may considerably deviate from a circular symmetry. A good example is diamond and graphite. That means it is more likely it will cool into hexagonal chunks. Pretty much any tiny dent made on the Moon's surface is going to stay there. 18. Texture will still be used but in a different sense than for igneous rocks. This icy bedrock is potentially unstable, and some impact craters may relax or fade away to unrecognition due to water ice's volatility and weak but strongly temperature dependent rheology. Glassy texture is the most readily recognized. Find more similar flip PDFs like Planetary_Geology. Very large impact craters greater than 300 kilometers (185 miles) across are called impact basins. Reuyl, Dirk. In the upper part, the flow field enables the rock masses to escape as ejecta from the growing excavation cavity. Coal is usually obvious to most students even though few people seem to have ever actually examined it up close. 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. 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. Cooling of the magma can occur beneath the surface (plutonic) or on the surface (volcanic). - Lunar and Planetary Institute More elongate craters can be produced if an impactor strikes the surface at a very low angle less than 20 degrees. Describe the breakage as either irregular or conchoidal (has the appearance of broken glass)HardnessResistance to scratching or abrasion.Use minerals of known hardness from the Mohs Hardness Kits. Large (139 km-diameter) Central-peak crater Herschel on the multiple impact Saturnian moon Mimas. The faster the incoming impactor, the larger the crater. T U ; = B } ~ x z h_X B* CJ ph h_X B* ph An extensive blanket of ejecta covers the area around the rim. endobj Olympus Mons is only one of four huge volcanoes in a 3000 km-wide region called Tharsis. Astronomy Gift Shop: http://www.astronomydvd.com/shop.aspx How were the Moon's craters and maria formed? 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? The crater was created instantly when a 50m, 150,000-ton meteor slammed into the desert about 50,000 years ago. Non-foliated textures have minerals that are not aligned. They are typically filled with impact rocks (impactites) in the form of impact melt rocks,suevitesand different kinds ofbreccias. 6 0 obj Fig. b. The 50 km-diameter Mathilde asteroid has a mean density of 1.3 g/cm only and is considered a kind of rubble pile. But until NASA returns to the lunar landscape, researchers must rely on shockwave simulators, mathematical models and the well-worn geological formations on Earth to estimate how and when another impact event might occur. Were still searching for a clue to deduce that.. Scratch the unknown mineral with a known hardness to determine which mineral is harder. 15. Mineral Physical Properties ChartPHYSICALPROPERTYDefinition*Testing MethodCleavageBreakage of a mineral along planes of weakness in the crystral structure.Examine the mineral for areas where the mineral is broken. endobj 20. It is colder inside some craters near the lunar poles than it is on the surface of Pluto (25K, or -415F). A complex crater in the northern region of Mars. What happens when an impactor hits? * Definitions simplified or modified from Bates, R.L. Fig. Impact Craters. (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. Fig. As mentioned above, the composition of most igneous rocks can be identified using this system, formally known as the Color Index. Reuyl, an early Hesperian crater, provides evidence for diverse fluvial events; Alluvial fans, channels, orthogonally superposed deposits, fan deposits with incised channels, and large deposits suggest fluvial activity; Two sinuous ridges associated with the alluvial fan on the crater floor are the oldest features of fluvial origin 7. Impact craters allow scientists to study a planet's geological historyeven when the records are buried beneath the surface. 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. These are impact craters, each of which was formed when an asteroid or comet collided with the Moon's surface. largest craters on Europa, Ganymede, and Callisto formed in an icy crust (Io's crust is dominated by silicates, see Chap ter 14). 11. Extensional stresses have led to the formation of great valleys such as Valles Marineris, the longest canyon system in the solar system. Once these two characteristics have been identified, the Igneous Rock Identification chart can be used to help identify the rock name. Therefore, crisp craters with upraised rims and steep sides are young, while less distinct and eroded craters with partial rims are probably older. A comparable process is observed with the peculiar shock-deformed Buntsandstein conglomerates in Spain and is in more detail explainedHERE. Spreading outwards from the point of contact, compressive shock waves are permanently reflected from the free target surface as tensile rarefaction waves of comparable intensities and, like the shock waves, are propagated downwards. Early in the formation of our solar system (before 3.9 billion years ago) there was lots of large debris striking the surfaces of the young planets and moons; these older impact basins are larger than the more recent craters. Privacy Policy| What process do you think formed Reuyl crater (marked B on Figure 5)? Justify your answer? Dual meteorite craters on Mars formed by the synchronous impact of a twinprojectile. 2) we may think it somehow formed from an identical mechanism. Continue doing this with harder or softer minerals from the kit until the hardness is determined.LusterCharacter of the light reflected by a mineral.Look at the sample to determine if the mineral is metallic in appearance (looks like a chunk of metal) or non-metallic (doesn't look like a chunk of metal).MagnetismElectromagnetic force generated by an object or electrical field.Use a magnet to determine if the magnet is attracted to the sample.Reaction to HClChemical interaction of hydrochloric acid and calcium carbonate (CaCO3).Place one small drop of HCl on a sample a watch for a reaction - effervesces (bubbles).Specific GravityRatio of the mass of a mineral to the mass of an equal volume of water.Generally not determined in an introductory lab. 7. Determination of the actual chemical composition and crytalline structure of a mineral is difficult without the proper equipment. 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. Fig. This flow field grows with time, and the rock mass flow is directed upwards, sideward and downwards. For the following, you will use the knowledge from previous questions to identify Martian landforms and describe the geologic processes that created them. Similar to some river systems on Earth, these Martian channels have a branching pattern. 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. 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. Larger impacts also still occur, but these are much more rare. Justify your answer. What process do you think formed Reuyl crater (marked B on Figure 11.5)? Smaller planets have less gravitational "pull" than large planets; impactors will strike at lower speeds. Press, Oxford, 1989. Igneous rocks can be identified by the determination of the composition and texture of the rock. Why does the Moon have so many craters while Earth has so few? Moreover, the polar caps contain some water ice. What process do you think formed Reuyl crater (marked B on Figure 5)? "It is difficult to say exactly . 16 0 obj 2. Oblong craters can be created by impacts striking the surface at a very low angle. In fact, the differences between craters provide a lot of information about how the craters formed, when they formed, and why. The excavation stage of impact cratering. in Reuyl crater located along the dichotomy boundary (west of Apollinaris Mons ). The reflected tensile stresses are insofar crucial as the tensile strength of rocks is much lower than the compressive strength. The greater the mass of the impactor, the greater the size of crater. Procedures and Questions: Part 5 Finally, let's examine Apollinaris Patera and surrounding region. Explain your answer. Lake Toba in Sumatra, the largest volcanic structure on Earth, is an example of an enormous caldera that has filled with water over time. A very rough rule of thumb amounts to the order of a one-to-ten diameter ratio. 10 12 exemplify typical terrestrial structures. 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. Sedimentary rocks are rocks composed of sediment. How the atoms and molecules are arranged and the strength of the bonding between the atoms result in different physical properties for different minerals. How looks an impact crater that was produced by an oblique impact? How does the mass of the projectile affect the cratering process? 9). Beware that even though an igneous rock may have a felsic composition (light color), the rock can contain dark colored minerals. : Impact cratering. Degraded craters -- Craters that have become eroded due to weathering, lava flows, impacting, or downslope movement of material. ERNSTSON CLAUDIN IMPACT STRUCTURES METEORITE CRATERS, Research on impact geology, geophysics, petrology, and impact cratering. NN `GF9A`U l8_g1g}=""Px2q$O@Y8)Oq-9O{2NW?`9:uMuBiO2qd]{%= LX'K {u/ 8`&_@ug,jbAM$[$oPocqM9K'5u"gY2;!1Nb$NfMc,cl9{=ZY6m#v]b1$m|"^K)Ks7q~B-=Cdl/)q&eHdiT) %Iwd`y\*/[Cr|R>/cRN]UyYIcF8`wiaV>bzw]'b+DZbV;zdge4e=00%9)q@B|~1QV, V=~ERZRm -Y Non-foliated textures are identified by their lack of planar character. First, the impactor rushes toward the surface. The more mass it has the bigger the impact. But Earth has several things the moon doesnt an atmosphere and liquid water that cause erosion. Mafic compositions are poor in silica, but rich in iron (Fe) and magnesium (Mg). The same chemical composition, but two different crystalline structures - therefore, two different minerals. The legend is shown at the bottom with different units or features present within the crater. % Gneissic banding is the easiest of the foliations to recognize. Reuyl Crater Central Peak, as seen by HiRISE. The four major geologic processes (gradation, impact cratering, tectonism, and volcanism) each produce distinct landforms. endobj Simple Craters . Some of this tiny debris makes it to Earth's surface and is mixed with soil and ocean sediment. Explain why you believe this is so. This crater is about 20 kilometers (12 miles) across and has a large central peak and terraces around its rim. However, this is not a sensible practice in a large lab with many different people handling the samples. eige6 | (Viking image 645A57) 6. Explain why you believe the way you do. Source: https://news.discovery.com/earth/how-are-craters-formed.html, Center for Planetary Exploration (CPEx) Opens at Stony Brook University. What process do you think formed Reuyl crater (marked B on Figure 11)? 4) What process do you think formed Apollinaris Patera, marked A? 9 0 obj must an impactor be to produce a given size impact structure? This means that the minerals in the rock are all aligned with each other. endstream Consult your lab manual for detailed discussion. Jackson (eds. Give evidence for your answer. The composition of clastic sedimentary rocks is divided into three types - clay/silt, sand and gravel. Mercury and the Moon are covered with impact craters; their surfaces are very old. Ds8d9B nNPS,*_y\v`/>wou__]ewPcLkUU$~z-S|lj O/#lr 9]_nc5u$9a4GVKwsaG|4ot6%?F3Xa:K1r=1\Sw Essentially, the Moon's surface has not been modified since early in its history, so most of its craters are still visible. Sinuous Ridge Materials in Reuyl Crater. 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. Volcanism has produced vast lava flows, broad shield volcanoes, and plains of volcanic material. Both are black in color, and is composed of carbon. Partner, Earth and Space Science News for Educators. 22. 3. And although these are abundant on the . Hesperia Planum, showing bright windstreaks associated with some of the craters. Tenoumer Crater. April 8, 2015. (a) Geomorphic map of Reuyl crater. (b) Contour map derived from the MOLA 463m/pixel DTM, with the . Tswaing Crater. Stresses can be caused by subsurface uplift or by the addition of mass (such as lava flows) that weigh down an area. endobj Transcript (121 KB) Overview : Impact cratering is, arguably, the most important and fundamental geological process in the Solar System. rought The right side of Figure 12.4 shows a rift zone on Venus. 1. and J.A. Justify your answer. 2 0 obj 14. 21. 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? 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. -Un+iJiO&Jsg/kO(*g!FcyvOC&t+3I*cm_5{`7=!MhW&A\8(}HOf%_Pp)G)d:owWt..L Look for areas where the light reflects from planar surfaces. 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. Unlike the rock-into-mud cratering, the excavation in impact cratering is inextricably linked with the propagation of shock waves. More about the doublet crater. There will be another Chicxulub-size impact event, he said. The impact velocity was 1250 m/s, and the target (flour) sound /seismic velocity is estimated to have been about 100 m/s. On Earth, impact craters are harder to recognize because of weathering and erosion of its surface. Obsidian is volcanic glass which erupts as a lava flow. When a meteor makes it through Earths atmosphere without burning up, it strikes the ground faster than the speed of sound. Valley systems cut through many of the cratered terrains of Mars and have characteristics analogous to water-cut valleys on Earth. The impact sprays material ejecta out in all directions. In an introductory level lab it is impossible for us to determine these two aspects of a mineral. The monument contains 55 cones with lava flows and 14 fissures, many of which have spatter cones. Very similar, but still different, therefore two different minerals. 03.04.10. <>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> The structure of the transient crater is widely preserved, and we are left with a simple or bowl-shaped impact crater (Fig. On Mars, meteor storms 100 million years ago may have literally shaken the Red Planet to the core and destroyed its magnetic field. The Crater Maker should stand over their sand-filled container and hold their arm out at the height they are going to drop it. Most obsidian is felsic in composition, yet typically it will have a very dark color (dark brown to black). The curious central mound within the craters can be explained by Hertzian and spallation fracturing on collision with the hard hailstones. Diameter 290 km. Space shuttle image STS51I-33-56AA, courtesy of the Lunar and Planetary Institute. 7 0 obj Source: Google Earth. Context Image. These are not commonly tested for in an introductory lab. * Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project Different chemical compositions result in different minerals. Anthracite coal is similar to bituminous coal. These fragments or clasts can be very fine (ash) or coarse (lapilli) or very coarse (bombs and blocks). 5. As lower levels of the lava start to cool, they are also pulled . 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. Material Type: Lab; Class: Sci Thought/Processes I; Subject: Honors Program; University: George Mason University; Term: Unknown 1989; Keep track of the craters you measured. endobj Calcite readily reacts with a small drop of HCl. Terms of Use, Copyright document.write(new Date().getFullYear()); The rule of thumb holds roughly true also for small-scale hypervelocity impact craters produced in the laboratory (Fig. 6). And again, one might suspect a process similar to rock tossed into mud. Slaty cleavage is composed of platy minerals that are too small to see. Moon craters are formed by volcanism and cratering. How many objects from space impact Earth each year? Cross sections of simple and complex impact craters. Halite is common table salt and is most easily identified by taste. The two most notable are obsidian and dunite. Download Planetary_Geology PDF for free. A crater is a bowl-shaped depression, or hollowed-out area, produced by the impact of a meteorite, volcanic activity, or an explosion. Further identification of non-foliated rocks is dependent on the composition of the minerals or components in the rock. 14): The crater is not much larger than the projectile. What process do you think formed Apollinaris Patera? The meter scale indicates water depth. Wind-produced features, called bright windstreaks, are associated with many craters. !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+ Code of Conduct Consider the relationship between Ma'adim Vallis and Gusev, the 160 km diameter crater marked D. Explain what could be the origin of the material that comprises the floor of Gusev? Scientists describe other types of craters as well: How are large craters different than small ones? Explain your answer. A peak ring crater (Clearwater West, Canada, 32 km diameter). When first we see images of the famous one-kilometer (0.75-mile) bowl-shaped Barringer meteorite crater in Arizona (Fig. Justify your answer. <> However, impacts still occur across our solar system, but at a reduced rate. : 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 -# -# ! Foliated textures show four types of foliation. ExDsD ;;8-E:(] endobj 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. A mystery concerning water on Mars is "Where did it go?" Typically, these rocks split along parallel, planar surfaces. 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 . 13). Different crystalline structures, or how the atoms and molecules are arranged, result in different minerals. 18. Image from the Viking Orbiter, courtesy of the Lunar and Planetary Institute. Impact basins are very large impact structures that are more than 300 kilometers (185 miles) in diameter. Figs. Sand and dust particles carried by the wind form dunes and windstreaks. Determine and record the diameter of the caldera structure (include the over all caldera structure in this measurement). 9). Apart from the distinct role rarefactions waves play in the formation of the excavation flow field, they are especially relevant geologically. 19). 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). It was named after British astronomer Axel Firsoff, and the name was approved in 2010.. Parts of the crater display many layers, as do some of the other craters in the region. Inclusion, Diversity, Equity & Accessibility (IDEA). 17 0 obj Mass movement is the displacement of material by landslides or slumping through the action of gravity. endobj However, there are exceptions. Sedimentary rock identification is primarily based on composition. Such a high-speed impact produces a crater that is approximately 20 times larger in diameter than the impacting object. 17. 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]. 4. 5 0 obj Valleys on western Chryse Planitia near Viking 1 site. The same geologic processes that shape Earth, i.e., erosion, impact cratering, tectonism, and volcanism, have left their mark on Mars. -+eh5 L*]>;ppq Aeolian (wind) activity is also a continuing process of erosion. 15 0 obj Tychos diameter is 85 km. <> The edges of these larger craters also may slump, creating terraces that step down into the crater. Southern cratered highlands. 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? stream These are fragments or pieces of rock or minerals. It is the oldest and largest impact crater recognized on Earth's surface. 4). This "period of heavy bombardment" ended by about 3.9 billion years ago. Limestone may or may not contain fossils. endobj Students, staff, and faculty at Stony Brook University are hard at work gathering data on the history of Mars. A bowl-shaped simple crater (Wolfe Creek, Australia, 900 m diameter). endobj and more. Below you will find a chart which defines the physical properties and provides the means for determining the physical property of a mineral sample. Scientists also think that faster cooling, like when lava is exposed to water, may also help with the formation of these columns. What process do you think formed Reuyl crater (marked B on Figure 11.5)? How scientists solved the riddle of these mysterious landforms. 16. 19. Igneous Rock Identification ChartCOMPOSITION \\\\\\\\\\\\\\\\ TEXTURE\\\\\\\FelsicIntermediateMaficUltramaficPegmatiticGranite PegmatiteDiorite PegmatiteGabbro PegmatitePhaneriticGraniteDioriteGabbroDuniteAphaniticRhyoliteAndesiteBasaltPorphyriticRhyoliteAndesiteBasaltGlassyObsidianBasaltic GlassVesicularPumiceScoriaPyroclasticVolcanic Tuff Composition of igneous rocks is properly identified by determination of the rocks chemical composition. Aphanitic texture is a fine grained texture but the crystals are too small to see. The Moon does not. by lava flows that obscured the older craters. 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.
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