LAB P - GLACIAL PROCESSES AND LANDSCAPES

Transcription

1 Introduction LAB P - GLACIAL PROCESSES AND LANDSCAPES Ice has been a significant force in modifying the surface of the earth at numerous times throughout Earth s history. Though more important during the Pleistocene Epoch (15,000 years before present), ice sheets and glaciers still actively modify the Earth at high elevations and polar latitudes. Ice serves as an agent of erosion, creating landforms both by the removal and deposition of earth materials. Materials needed: pencil, textbook, atlas, topographic maps of Whitewater, Wisconsin, Jackson, Michigan and Bering Glacier, Alaska Quadrangle map sheets, assorted aerial photos (provided by instructor). Part I. Answer the following questions. A. Where are the two largest continental glaciers in existence today? B. Name two countries where alpine glaciation is actively modifying the landscape today. C. Define the terms accumulation and ablation in terms of glacier mass balance. D. Glacier Mass Balance 1. Describe in terms of accumulation and ablation, the glacial mass balance for a. an advancing glacier: b. a retreating glacier: 2. What does it mean when a glacier is in a state of dynamic equilibrium? 3. What is happening to the snout of the glacier if it is in dynamic equilibrium? 4. Describe the movement of the glacial ice and the earth materials within or on the ice? 5. What specific depositional feature is created by a glacier while in a state of dynamic equilibrium? E. Fluvial or water action generally produces V shaped valleys, often meandering, following P-1

2 the path of least resistance. When glaciers move down these same valleys, what type of landscape modification takes place? Part II. Using the Whitewater Quadrangle and Jackson Quadrangle map sheet, answer the following questions: A. What type of glacier created the terrain portrayed on the Whitewater and Jackson quadrangles? What is it about the terrain that led you to this conclusion? B. What are the names of the glacial features at the following locations? Choose from the list on page P-5. Following the identification of the feature, put an E for Erosional process or a D for Depositional process in the third column. Finally, describe in a sentence or two how the feature was formed. Feature Location Feature Name E/D How was it formed? C. Where in relationship to the ground surface would you find the water table? What common feature on these two maps is indicative of the position of the water table? P-2

3 D. Besides agriculture (dairy), what other economic activity is key on the Whitewater map? Part III. Using the Crystal Productions Landforms Set 2 #15, Drumlins, East of Rochester, NY, answer the following questions. Note: 15A goes on the left side of the stereoscope. 1. Which way are the drumlins oriented? N/S or E/W 2. Which way did the glacier come from? How do you know? 3. Can you tell which direction the river is flowing? How? Part IV. Using the Bering Glacier Quadrangle map sheet, answer the following questions: A. What type of glacier(s) is/are responsible for this terrain? Support the answer with specific map information. B. Are the following locations situated in glacial zones of accumulation or ablation for the Bering Glacier? N, W = N, W = N, W = N, W = C. What does the purple-screened pattern on the glacial features (lower left of map) indicate? P-3

4 D. What are the names of the glacial features at the following locations? Choose from the list on the page P-5. Following the identification of the feature, put an E for Erosional process or a D for Depositional process in the third column. Finally, describe in a sentence or two how the feature was formed. Feature Location Feature Name E/D How was it formed? E. What is the name and elevation of the highest point on the map? Name = Elevation = P-4

5 F. Name glaciers that have one or more of the following: Lateral moraines Terminal moraines Medial moraines Ground moraines G. What type of drainage pattern does Granite Creek have? In which compass direction does it flow? H. What are the coordinates and elevation for Kagett Point (T21S, R24E). I. What process is responsible for the small lakes at West Creek? J. The wide reddish brown line crossing the entire map indicates some type of boundary. What is the boundary for? Part V. Using the Crystal Productions Landforms Set 1 #9, Mount Bonneville, WY, answer the following questions. 1. What type of glacier is this? 2. What landforms can you discern? List of possible glacial landforms. Horn Roche Moutonée Drumlin Esker Col Arête Lateral Moraine Terminal Moraine Cirque U-shaped valley Recession Moraine Kame Hanging Valley Truncated Spur Ridge Fiord Paternoster Lakes Knob and Kettle Topography Tarn Medial Moraine Interlobate Moraine Ice Fall Kettle Lake Kettle Outwash Plain Till Plain Valley Train P-5