Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Climate and Sediment Summary Students investigate the different kinds of sediments present at different locations on the ocean floor. Learning Objectives Students will be able to: • Interpret a sediment map of the ocean basins. • Predict the sediment type they will find at a given location. • Describe their observations of a sediment core. National Science Education Content Standards • Grades 5–8: Earth and Space Science: Structure of the earth system • Grades 9–12: Earth and Space Science: Origin and evolution of the earth system TM Teaching for Science • Learning for Life | www.deepearthacademy.org Ocean Literacy Essential Principles • Earth has one big ocean with many features. • The ocean and life in the ocean shape the features of Earth. Target Age: Grades 7-12 Time: 40 minutes Materials • Core replicas or core photos of ODP Leg 208-1262B-15H-3, IODP Expedition 303-1308A-6H-1, and the K/T boundary core (ODP Leg 171B) To inquire about the availability of core replicas, contact Deep Earth Academy at [email protected]. The respective core photographs are available at: http://www-odp.tamu.edu/ publications/208_IR/208TOC.HTM. Scroll down and click on Images. Scroll to image 1262B15H.PDF. http://publications.iodp.org/ proceedings/303_306/EXP_REPT/ CORES/IMAGES/. Scroll down to image 1308A6H.PDF. http://www-odp.tamu.edu/ publications/171B_IR/IMAGES.HTM. (Images: 1049A17X.PDF, 1049B8H.PDF). Background This activity focuses on the sediment of the open ocean (as opposed to continental margins). Along continental margins a majority of the sediment found is terrigenous—derived from pre-existing rock. This type of sediment is eroded from landmasses and transported to the margins usually by water (e.g., rivers, streams). Once it enters the ocean, this sediment is rapidly deposited. Ice-rafted debris is also terrigenous in origin, but its mode of transport is much more unique than rivers. As the name implies, icerafted debris is transported and deposited by icebergs, ice floes and other forms of floating ice associated with glacial advance and retreat. The distribution of ice-rafted debris is very limited, as it can only occur where glaciers are found—in polar regions. In tropical regions, the dominant sediment type is biogenic— produced by organisms. Finally, there is the temperate region. The sediment found in this region can vary as greatly as the region’s climate conditions. Climate and Sediment What to do investigations on the core replicas or photos, allowing adequate time to examine each core replica. 1. Set out core replicas at stations around the room. 2. Ask your class to describe the climate found in polar, temperate and tropical regions. Make a chart on a board or flip chart. 5. When all the groups are finished, lead a class discussion of their answers. In particular, gather the class around each core replica to look closely at its composition and discuss what they see. 3. Once you have some answers up, ask students to predict what type of sediment they would expect to find in each area. Write these predictions on your chart. Submitted by 4. Hand out the student page and instruct students to work in groups to complete the Dr. Beth Christensen, Adelphi University and Catherine Wiltsey, Adelphi University TM Teaching for Science • Learning for Life | www.oceanleadership.org During ODP Leg 208, sedimentologists Zhifei Liu (China) and Susan Keller (USA) used surgical precision to microsample cores with sediments deposited during the Paleocene/Eocene Thermal Maximum. 2 Climate and Sediment Student Page Background this location? Now examine the core replica or photograph of this area for Site 1262. What types of sediment are present? Climate is the long-term weather of a region. It plays a big part in determining the type of sediment found in an area. Earth is divided into three climate zones: tropical, temperate and polar. The tropical zone is the section of the planet centered on the equator. It is bounded to the north by the Tropic of Cancer and to the south by the Tropic of Capricorn. The tropics extend from about 23° 30’ N through the equator (0°) to 23°30’ S. Typically, the tropics have a hot, moist climate. 5. Integrated Ocean Drilling Program (IODP) Expedition 303 recovered cores from the North Atlantic. What type of sediment would you expect to find at this location? Now examine the core replica of this area. What type of sediment is present? 6. The core of Leg 171B shows the K/T boundary. This core was recovered from the Blake Plateau off the East Coast of the United States. What type of sediment would you expect to be present? Examine the core. What kind of sediment do you observe? There are two temperate zones, one in each hemisphere. In the Northern Hemisphere, the temperate zone extends from the Tropic of Cancer to the Arctic Circle (66° 30’ N). The southern temperate zone extends from the Tropic of Capricorn to the Antarctic Circle (66° 30’ S). Though there can be days or short periods of extreme hot or cold temperatures in the temperate zone, the climate of this area is typically mild. There is a subtle progression through the four seasons. TM Teaching for Science • Learning for Life | www.oceanleadership.org Beyond the temperate zones lie the polar regions. The northern polar region is defined by the Arctic Circle and the North Pole (90° N), while the southern polar region is defined by the Antarctic Circle and the South Pole (90° S). Polar zones are dominated by the polar ice caps. Activities Answer the following questions using the attached sediment distribution diagram. Think about the relationship between climate and biology. Further Exploration As seen in the sediment distribution diagram, sediment distribution changes as you move from continental margins to the deep ocean. What types of sediments are found on continental margins that are not found in the open ocean? Why do you think this happens? 1. Find the tropical zone on this map. What types of sediments are present? What type dominates? Why? 2. Find the temperate zone. What types of sediments are present? What type dominates? Why? 3. Find the polar region. What types of sediments are present? What type dominates? Why? 4. Using the Ocean Drilling Program site location map on this page, find the location of the drill site for Leg 208 on the Walvis Ridge. What type of sediment would you expect to find at 3 Figure: Copyright 2005, The McGraw-Hill Companies, Inc. From “An Introduction to the World’s Oceans” (8th edition), K. Sverdrup, A. Duxbury, and A. Duxbury, Used with permission. TM Teaching for Science • Learning for Life | www.oceanleadership.org Sediment Distribution in the World’s Oceans Climate and Sediment 4