Coming or Going: Where Does Antarctica's Ice Fit In?

Overview

The long-term objective of PolarTREC teacher Lesley Urasky's expedition research in Antarctica (Glacial History in Antarctica) is to determine the rate at which glaciers have receded since the Last Glacial Maximum. This lesson is designed to give students an understanding of the Last Glacial Maximum, the climatic conditions that lead to glacial periods, and how the rate of glacial retreat can be determined. Students will have an opportunity to use real data collected by researcher John Stone (University of Washington) and his teams from earlier expeditions to glaciers along the Transantarctic Mountains in Antarctica.

Objectives

• To be able to describe the climatic and geographic (sea level and ice sheet coverage) conditions that existed during the Last Glacial Maximum
• To be able to compare the climatic and geographic conditions of the Last Glacial Maximum to the Present
• To be able to describe how past climates can be reconstructed using a glacier's equilibrium line altitude (ELA) and glacial ice cores
• To be able to accurately plot exposure age data and use this data to determine the rate of glacial retreat.
• To be able to plot sample locations accurately on a topographic map and link these geographic locations and glacial retreat rates to climate changes across geologic time.

Lesson Preparation

The basics of glacial morphology, formation, and movement may need to be addressed prior to conducting these activities. Students will need to understand the basics of glacial growth and retreat in order to fully comprehend how knowledge of a glacier's ELA helps scientists understand past climate. The links to several internet-based interactive tutorials and activities on glaciers have been given at the end of this document.

To prepare for Part I: What is the Last Glacial Maximum (LGM)?, teachers need access to a computer and LCD projector to show the PowerPoint presentation. Colored pencils and rulers need to be available to students for completion of the Dome C (EPICA) ice core diagram. It may also be helpful to either show students or have them work through the following websites:

• Rocky Mountain National Park: Glaciers and Glacier Change - Timeline of Recent Ice Ages interactive (http://www.nps.gov/features/romo/feat0001/BasicsIceAges.html)
• Rocky Mountain National Park: Glaciers and Glacier Change – Glaciers and Climate interactive (http://www.nps.gov/features/romo/feat0001/BasicsGlcClim.html)

To prepare for Part II: Climate Change and Glacial Size, teachers need to decide if students will be graphing the data by hand or will use Microsoft Excel. There are two different files included: a hard copy Global ELA data table as well as an Excel file containing Global ELA data. The one used will depend upon the selected method of data analysis. There is also a separate document that gives brief descriptions of how to graph the data using Excel in case this is an unfamiliar method.

To prepare for Part III: Antarctic Glacial Retreat Analysis, teachers need to decide if students will be graphing the data by hand or will use Microsoft Excel. There are two different files included: a hard copy set of data for the following locations: Ford Ranges, Marie Byrd Land; Reedy Glacier; and Mt. Rigby, Scott Glacier as well as an Excel file containing data for these sampling sites.

The topographic maps for the Ford Ranges and Reedy Glacier will need to be copied for each student or group of students. Each of these maps is in two parts, a right and a left side, which will need to be assembled after copying (unless the copier supports extra-large pieces of paper). There is a red line on each of the map halves indicating where the maps join together. Depending upon the age of the students and/or their experience with topographic maps, the teacher may want to enlarge the maps when copying them. (If they are enlarged, make sure each one is enlarged by the same percentage.) If this exercise is planned for several classes, laminating the assembled maps is highly suggested.

Procedure

Part I: What is the Last Glacial Maximum (LGM)?

The PowerPoint presentation "The Last Glacial Maximum" is shown to students. While viewing the presentation, students will complete the accompanying worksheet. After completing the presentation portion of the lesson, students will read the background information given about the glacial and interglacial periods of the Quaternary. Using the given explanation of how scientists use glacial ice cores to determine the climate at the time a glacier formed, students will complete the diagram of Dome C from the European Project for Ice Coring in Antarctica (EPICA) and answer the following questions.

Part II: Climate Change and Glacial Size

After reading the background information about glacial equilibrium line altitudes, students will plot the climate data for the 70 glaciers. They may plot them either by hand or use the Excel file to create a scatter graph. Using the background information along with the student-generated graph, students will answer the analysis questions.

Part III: Antarctic Glacial Retreat Analysis

Students will create three graphs from the retreat data for each of the sample sites: Ford Ranges, Marie Byrd Land; Reedy Glacier; and Mt. Rigby on Scott Glacier. Using these graphs, they will draw trend lines for each of the data sets and calculate the rate of retreat of the glacier at each of the sample sites. The Ford Ranges and Reedy Glacier sample sites will be plotted on their respective topographic maps, while the three general sample locations will be plotted on a map of the Antarctic continent. Using all of these resources (graphs with trend lines, completed data tables showing rate of retreat, and the background information), students will answer the analysis questions.

Extension

n/a

Resources

• Rocky Mountain National Park: Glaciers and Glacier Change - Timeline of Recent Ice Ages interactive http://www.nps.gov/features/romo/feat0001/BasicsIceAges.html
• Rocky Mountain National Park: Glaciers and Glacier Change - Glaciers and Landscapes interactive http://www.nps.gov/features/romo/feat0001/BasicsGlcLandscape.html
• Rocky Mountain National Park: Glaciers and Glacier Change – Glaciers and Climate interactive http://www.nps.gov/features/romo/feat0001/BasicsGlcClim.html
• NOVA: Mountain of Ice – Life Cycle of a Glacier http://www.pbs.org/wgbh/nova/vinson/glacier.html
• Using ice cores to understand past climates: http://www.antarctica.ac.uk/bas_research/science/climate/icecore/page1.php
• NOAA Paleoclimatology: Exploring Weather and Climate Change Through the Powers of 10 http://www.ncdc.noaa.gov/paleo/ctl/
• Interactive computer simulation of glaciers and their movement: http://phet.colorado.edu/en/simulation/glaciers
• Interactive flashcards on glacial vocabulary: http://quizlet.com/16231986/noaa-glaciers-flash-cards/

Assessment

Summative assessment: Parts I, II, and III of the lesson. Teacher answer key is provided. All three parts may be completed together, or each one can stand alone.

Credits

Lesley Urasky, PolarTREC Teacher 2010-2011, lurasky [at] crb1.k12.wy.us or polarchick1 [at] gmail.com
Parts I and II of this lesson were adapted from the following source:

• Anderson, D. (n.d.). Glacial landscapes: Past climate and glaciation of the Drakensberg Mountains, southern Africa. Retrieved January 4, 2013, from Royal Geographical Society with Institute of British Geographers: http://www.rgs.org/OurWork/Schools/Teaching+resources/Key+Stage+5+resources/Key+Stage+5+-+From+the+field+resources/Glacial+landscapes/Glacial+landscapes.htm Data for Part III is a result of research conducted in Antarctica by Dr. John Stone and colleagues of the University of Washington:
• Complete data sets can be found at the following sites: Stone J.O., Balco G., Sugden D.E., Caffee M.W., Sass L.C. III, Cowdery S.G. and Siddoway C. (2003) Late Holocene deglaciation of Marie Byrd Land, West Antarctica Science 299, 99-102. Input data for cosmogenic Be-10 calculations, Mt Rigby, Scott Glacier retrieved from: http://depts.washington.edu/cosmolab/data/Scott_Glacier_exp_ages.html Exposure ages: Reedy Glacier, Antarctica retrieved from: http://depts.washington.edu/cosmolab/data/Reedy_Glacier_exp_ages.html