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Where to Look? Teacher’s Information Standards: Grade 6 Illinois State Goal
11 Grade 8 Topics: Planning and research
are more important than luck in finding dinosaurs Research and hard work play a much larger role in finding dinosaurs than luck. Information from maps and reports is combined to determine where dinosaur bones might be found. Geographic maps are used to plan vehicle routes and campsites and to identify exposed areas of rock where fossils might be found. Geologic maps are used to find terrestrial rocks of Mesozoic age (formed in the dinosaur era). Scientific reports describe previous discoveries and often mention whether fossil fragments were found from an area. Materials: Copy of Where to Look
Panel Teacher’s Directions: Make sure that the students understand the difference between geographic and geologic map. These are different maps of the same area. This can be demonstrated by cutting the maps apart, overlapping them, and holding them in front of a window. The city names and roads on both maps will line up. The decision of where to search for fossils is based on information on both maps. Where to Look? Luck plays a part in finding fossils, but research and hard work play a larger role. The expedition team uses geographic maps, geologic maps, and scientific reports to decide where to look for dinosaur fossils in Niger. A geographic maps shows cities, villages, roads, trails, and surface features (dry river beds, sandy areas, cliffs, mountains), as well as areas of exposed rock not covered by dirt, sand, or grass, which might yield fossils. The team uses this kind of map to plan campsites and vehicle routes. A geologic maps shows the ages and kinds of rock that form the surface of the land. The team uses geologic maps to find rocks that formed during the dinosaur era. Geologists have mapped each distinct rock layer and have given each layer a different color and letter symbol. For example Cretaceous rocks (145 to 65 million years old) are shown on geologic maps as different shades of green and labeled with the letter K. The key on the geologic maps gives more information about the type of rock that composes each area. Some rock types include marine (formed in the ocean floor), terrestrial (formed on land), and volcanic (formed by volcanoes). The team is interested in terrestrial rocks because those will be the ones that contain the fossil bones of the animals that lived on land. To look for Cretaceous dinosaurs, the team locates Cretaceous (green) areas in the maps and checks the key to make sure the rocks in these areas are terrestrial. Scientific reports describe scientific discoveries. Before the team departed, they went to a library and found all the reports that described Niger, its geology, and its fossils. The team decided where to look by combing information from geographic maps, geologic maps, and scientific reports. Hunting Dinosaurs Background Information Luck plays only a small part in discovering fossils. Paleontologists use three sources of information to decide where to search:
The geographic maps shows you the location of the cities, roads, major sand dunes, and mountains. With this type of map you can also determine which areas are covered by sand or trees. The geologic map tells the age of the rocks (mammal era, dinosaur era, or older). Dinosaurs are found only in the rocks of Mesozoic age (dinosaur era). These rocks are divided into three time periods: Mesozoic Era
A geologic map also indicates where the rocks were formed (on land, in the sea, or in a volcano). Dinosaurs are almost always found in terrestrial rocks (formed on land). Dinosaurs or other land animals are never found in volcanic rocks and are rarely found in marine rocks. From a geologic map, therefore, you can determine the ages and the types of rock in a region. Directions You are a paleontologist and want to discover new Cretaceous dinosaurs in the Sahara Desert in Africa. First, you go to the library to look for previous scientific reports on the area. You find one report with pictures of large pieces of fossil bones that look like they might belong to a dinosaur. The report also mentions that there is a large area of exposed rock where the fossil fragments were found. This sounds interesting, but there is no map that shows exactly where the fossil fragments were found. All you know is that the fossils were found somewhere near an oasis called In Gall. You return to the library to study maps of the area. You find a geographic map and a geologic map of the area (see next page). Now you have the information you need to lead an expedition to the area and decide the best place to look for fossils. Map Key: Rock Age: T Tertiary rocks (mammal era) C Cretaceous rocks J Jurassic rocks Tr Triassic rocks P Paleozoic rocks (pre-dinosaur)
Rock Type: t terrestrial m marine v volcanic 1. Can the town of In Gall be reached by truck? Do you need to pass through any other towns? 2. What is the area around In Gall like? Where is the rock covered by sand or trees? (HINT: Describe your answer using the compass directions by saying “North of In Gall there are…”. See the compass below the maps.) 3. Determine the ages and types of the rocks by locating the rock age symbols (T, C, J, etc.) and the rock type symbols (t, m, v) in the map key. Do you think it is possible to find dinosaurs of Triassic age in this area? Why or why not? 4. You need to know where to search for Cretaceous dinosaurs. Are there rocks of Cretaceous age? If so, are any of these Cretaceous rocks terrestrial (formed on land)? Color in this rock area on the geologic map with your pencil. If terrestrial Cretaceous rocks exist in the map area, are any exposed at the surface? (HINT: Look at the geographic map for areas no covered by dunes) 5. If you were camping in In Gall, where would you take your team to search for new Cretaceous dinosaurs? (HINT: You must give a direction from In Gall, using the compass, and a distance from In Gall, using the distance scale under the map) Earth Science Links: United States Geological Survey http://www.usgs.gov- From the homepage of the U.S. Geological Survey you can get USGS information on your state, ask a card-carrying geologist your geology questions, find maps of almost anywhere in the country, check out the educational resources, and much more. Web Geological Time Machine http://www.ucmp.berkeley.edu/help/timeform.html- UC Berkeley’s Museum of Paleontology Web Geological Time Machine offers a geological time line with information and pictures about each period from the Holocene to the Hadean. The Continental Drift Cam http://www.en.com/danp/pixs/cams/cd-cam.htm- The Continental Drift Cam allows you to monitor the progress of continental drift without having to take the time from your bust schedule to go into the field and make tedious measurements. Climate and Continental Drift http://home.earthlink.net/~djbwx/projects/continental.html- A Emporia State University graduate student’s report explains the relationship between climate and continental drift and provides a map showing how continents have shifted over 225 million years. Geology Classroom Activities http://volcano.und.nodak.edu/vwdocs/vwlessons/plate_tectonics/introduction.html- From the University of North Dakota, a variety of classroom activities for all grade levels explaining plate tectonics and geology. A Teacher’s Guide is available. USGS What do Maps Show http://www.usgs.gov/education/teacher/what-do-maps-show/- A USGS classroom activity (with a link to a Teacher’s Guide) for 5-8 graders that explain how to read maps, including a lesson on topographic maps, and what kinds of different information are on different types of maps. Earth Science Bibliography: Busbey, A., The Nature Company Guide to Rocks and Fossils (Time Life Inc, San Francisco, CA, 1996) $16.95. Cassidy, J., EARTHSEARCH: A Kid’s Geography Museum in a Book (Klutz Press, Palo Alto, CA., 1993) $19.95. Cole, J., The Magic School Bus Inside the Earth (Scholastic, Inc. New York, 1987) $4.95. Deike, Ruth, Stone Wall Secrets Teacher’s Guide: Exploring Geology in the Classroom. (Tilbury House, Maine, 1998) $9.95. Lambert, D., The Field Guide to Geology (Facts on File, Inc. New York, 1998) $14.95. Lobek, A., Things Maps Don’t Tell Us: An Adventure into Map Interpretation (University of Chicago Press, 1993) $19.95. Parker, S., Rocks and Minerals (DK Publishers, New York, 1997) $5.95. Oliver, R., Rocks and Fossils (Random House, New York, 1993) $16.95. Pierre, Y., Mapping a Changing World (Thomasson-Grant & Lickle, New York, 1996) $17.95. Rhodes, F., A Golden Guide to Geology (Golden Books, New York, 1991) $5.95. Thorson, K., Stone Wall Secrets (Tilbury House Publishers, Maine, 1998) $16.95. Wiggers, R., The Amateur Geologist; Explorations and Investigations (Franklin Watts, 1994) $6.95. Earth Science Glossary: active margins: where colliding continental and oceanic plates trigger volcanic eruptions, earthquakes, and mountain building Cenozoic Era: 65mya to present; Era associated with the development of and domination by mammals correlation: the process geologists use to relate rock layers in area to rock layers from another area Cretaceous Period: last period of the Mesozoic Era; time period during which dinosaurs became extinct: “creta” comes from Latin, meaning chalk crust: earth’s outer surface; ranges from 4 miles : 40 miles thick crystal: a solid form of mineral with a regular, geometrical shape erosion: wearing away of the earth’s surface due to heat, wind and water excavate: to dig-up or unearth formation: a group of rock layers that are recognizable from one place to another fossil: the remains of a living thing, or direct evidence of its presence, preserved in rocks. usually only hard parts such as bones, teeth, and shells are preserved by burial or chemical change fossil record: the history of life on earth as revealed by fossils geographic map: depicts the location of cities, roads, major land formations geologic column: shows rock units as they were laid down in sequence geologic map: depicts the age of rocks (ancient, dinosaur age, or mammal age) and under what conditions the rock formed (on land, in the sea, on a volcano) geologist: a scientist who studies the structure of the earth and its rocks Gondwana: southern portion of Pangaea; consisted of the present day continents of Africa, Australia, South American and Antarctica igneous rocks: formed when melted rock in volcanoes or under the earth’s surface cools and hardens (also known as volcanic, intrusive or extrusive) index fossils: a fossil that provides precise correlation because it: has recognizable unique features, a wide distribution and is present in the geologic record for only a limited time. inner core: a solid ball inside the middle of the earth; 1540 miles thick; intense pressure keeps the inner core solid despite a temperature of 3700 degrees C Jurassic Period: second period of the Mesozoic Era; time period during which Pangea began to rift apart’ :”Jurassic” comes from fossil-bearing limestone rocks found in Europe’s Jura Mountains Laurasia: northern portion of Pangaea; consisted of the present day continents of North America, Europe and Asia magma: hot molten rock formed beneath the earth’s surface. mantle: layer of rock between the earth’s crust and outer core; 1800 miles think; semi-molten and denser than crustal rock marine rock: rock that formed in the ocean (i.e. limestone) metamorphic rocks: formed when igneous or sedimentary rocks are subjected to extreme heat and pressure, causing them to bend, fold, squeeze and literally, “change” shape and composition. Mesozoic Era: 248-65 million years ago; geologic time period during which dinosaurs lived; composed of the Triassic, Jurassic and Cretaceous Periods outer core: layer of dense, molten rock between the mantle and the inner core; 140 miles thick; may be mainly iron and nickel Paleozoic Era: 540-248 million years ago Pangaea: an ancient supercontinent composed of all the major continents we recognize today petrified: literally “turned to stone,” Petrification is the long process by which organic material is replaced by rock materials plate tectonics: term geologists use to describe the study of the movement of the plates under the earth’s crust. Most plates are composed of two parts: ocean floor and continental crust prospect: to explore or search relative age: age of a rock or fossil compared to another (i.e. “younger than” or “older than” relative to another fossil or rock) rift: to break apart rock section: a clean surface with rock exposed sedimentary rocks: most form on from particles eroded from rocks on land; some form from dissolved chemicals or organic particles from shells or other living organisms subduction zone: area where oceanic plates move into the mantle topographic map: map that depicts the changing elevation of a surface Triassic Period: first period of the Mesozoic Era; time period when dinosaurs first evolved; “Triassic” comes from Latin, “trias” describing three particular rock layers in Germany ventifacts: sand-blasted stones with flat, smoothed surfaces that have been eroded by wind over prolonged exposure volcano: an opening through which molten rock comes from deep inside the earth. |
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