1. EARTH SCIENCE Prentice Hall EARTH SCIENCE Tarbuck Lutgens 

2. 7 Chapter 7 Glaciers, Desert, and Wind Georgia Performance Standards: SES3: Students will explore the actions of water, wind, ice, and gravity that create landforms and systems of landforms (landscapes). a.Describe how surface water and groundwater act as the major agents of physical and chemical weathering. d.Explain the processes that transport and deposit material in terrestrial and marine sedimentary basins, which result, over time, in sedimentary rock.

3. 7 Chapter 7 Learning Objectives Student will be able to… 1.Differentiate the two types of glaciers. 2.Explain how glaciers move and describe the different types of glacial drift. 3.Identify the landscape features that glaciers form. 4.Summarize the causes of the most recent ice age. 5.Define key vocabulary terms on page 188.

4. What is a glacier? 7.1 Glaciers The ice age was a period of time when much of the Earth was covered in glaciers.  A glacier is a thick ice mass that forms above the snowline over hundreds or thousands of years.  YouTube Video (1:48): https://www.youtube.com/watch?v=fleX P9ljZ-o https://www.youtube.com/watch?v=fleX P9ljZ-o

5. Types of Glaciers 7.1 Glaciers  Valley Glaciers I ce masses that slowly advance down mountain valleys originally occupied by streams. A stream of ice that flows between steep rock walls from near the top of the mountain valley.

6. 7.1 Glaciers  Valley Glaciers

7. 7.1 Glaciers  Ice Sheets Ice sheets are enormous ice masses that flow in all directions from one or more centers and cover everything but the highest land. Ice sheets are sometimes called continental ice sheets because they cover large regions where the climate is extremely cold. They are huge compared to valley glaciers. They currently cover Greenland and Antarctica.

8. 7.1 Glaciers  Ice Sheets

9. Currently Continental Ice Sheets Cover Greenland and Antarctica

10. How Glaciers Move 7.1 Glaciers  The movement of glaciers is referred to as flow, and it happens in two ways. 1. Plastic flow—involves movement within the ice 2. Basal slip—slipping and sliding downward due to gravity The glacial budget is the balance, or lack of balance, between accumulation at the upper end of a glacier and loss, or wastage, at the lower end.  Budget of a Glacier

11. How a Glacier Moves

12. Calving

13. Reviewing Concepts Answer the following questions via short response. 1.What are the two types of glaciers, and where is each type found? 2.Describe how glaciers move. Critical Thinking Question: 3.Global warming is causing glaciers to melt all over the world. What is the environmental impact of melting glaciers?

14. Reflection/Summary

15. Glacial Erosion & Landforms 7.1 Glaciers

16. Glacial Erosion 7.1 Glaciers  Many landscapes were changed by the widespread glaciers of the recent ice age. Plucking—lifting of rock blocks  How Glaciers Erode

17. Glacial Erosion 7.1 Glaciers -Rock flour (pulverized rock)  How Glaciers Erode “Continued” Abrasion

18. 7.1 Glaciers - Striations (grooves in the bedrock) Abrasion  How Glaciers Erode “Continued”

19. Landforms Created by Glacial Erosion 7.1 Glaciers  Glaciers are responsible for a variety of erosional landscape features, such as glacial troughs, hanging valleys, cirques, arêtes, and horns.

20. Erosional Landforms Caused by Valley Glaciers

21. 7.1 Glaciers A glacial trough is a U-shaped valley that was once V-shaped but was deepen by a glacier.  Glaciated Valleys

22. Landforms Created by Glacial Erosion 7.1 Glaciers  A cirque is a bowl- shaped depression at the head of a glacial valley.

23. Landforms Created by Glacial Erosion 7.1 Glaciers Snaking, sharp-edged ridges called arêtes and sharp pyramid-like peaks called horns project above mountain landscapes.  Arêtes and Horns

24. Landforms Created by Glacial Erosion 7.1 Glaciers A tributary valley entering a main valley at a much higher level.  Hanging Valley

25. Erosional Landforms Caused by Valley Glaciers 1 2 3 4 5

26. Landforms Created by Glacial Erosion 7.1 Glaciers  Glacial Landforms Erosion| Glacier Melting and Calving (3:12)Glacial Landforms Erosion| Glacier Melting and Calving (3:12)  Awesome Glacier Iceberg Time Lapse (4:57)Awesome Glacier Iceberg Time Lapse (4:57)

27. Reflection/Summary

28. Glacial Deposits 7.1 Glaciers There are two types of glacial drift.  Types of Glacial Drift Glacial drift applies to all sediments of glacial origin, no matter how, where, or in what form they were deposited. 1. Till is material deposited directly by the glacier. 2. Stratified drift is sediment laid down by glacial meltwater.

29. Moraines, Outwash Plains, and Kettles 7.1 Glaciers Moraines—layers or ridges of till  Glaciers are responsible for a variety of depositional features, including - Lateral - Medial - End - Ground - Terminal end - Recessional end

30. Medial Moraine

31. Moraines, Outwash Plains, and Kettles 7.1 Glaciers outwash plains—sloping plains consisting of deposits from meltwater streams in front of the margin of an ice sheet  Glaciers are responsible for a variety of depositional features, including kettles—depressions created when a block of ice becomes lodged in glacial deposits and subsequently melts

32. Moraines, Outwash Plains, and Kettles 7.1 Glaciers  Glaciers are responsible for a variety of depositional features, including drumlins—streamlined, asymmetrical hills composed of glacial dirt eskers—ridges composed largely of sand and gravel deposited by a stream flowing beneath a glacier near its terminus

33. The Last Ice Age

34. Glaciers of the Ice age 7.1 Glaciers  The Last Ice Age Began 2 to 3 million years ago Division of geological time is called the Pleistocene epoch; it’s also the period when Homo sapiens evolved Ice covered 30% of Earth's land area. Greatly affected drainage The name Pleistocene is the combination of two Greek words: pleistos (meaning “most”) and kainos (meaning “new” or “recent”).

35. Defining the Epoch 7.1 Glaciers  The Last Ice Age Although scientists haven’t been able to determine the exact causes, changes in ocean current, composition of the atmosphere, and position of the Earth in relation to the sun are believed to be key contributors

36. Life During the Ice Age 7.1 Glaciers While Homo sapiens evolved, many vertebrates, especially large mammals, succumbed to the harsh conditions of this period (i.e., wooly mammoth, giant ground sloths, and mastodons). Note: dinosaurs did not existed during this period Most birds flourished – except the flightless species Vegetation was fairly limited With the extinction of large Ice Animals, the Neanderthals soon followed due to starvation

37. Extent of the Northern Hemisphere Ice Sheets

39. The History of the Ice Age Era YouTube Video (41.54)

40. Reflection/Summary

41. Geologic Processes in Arid Climates 7.2 Deserts Not as effective as in humid regions  Weathering Much of the weathered debris in deserts results from mechanical weathering. Chemical weathering is not completely absent in deserts. Over long time spans, clay and thin soils do form.  The Role of Water In the desert, most streams are ephemeral—they only carry water after it rains.

42. A Dry Stream Desert Channel Before and After a Heavy Rainfall

43. Basin and Range: A Desert Landscape 7.2 Deserts playa lake—a flat area on the floor of an undrained desert basin (playa) that fills and becomes a lake after heavy rain  Most desert streams dry up long before they ever reach the ocean. The streams are quickly depleted by evaporation and soil infiltration. alluvial fan—a fan-shaped deposit of sediment formed when a stream’s slope is abruptly reduced  Interior drainage into basins produces

44. Alluvial Fans

45. Basin and Range: A Desert Landscape  Most desert erosion results from running water. Although wind erosion is more significant in deserts than elsewhere, water does most of the erosional work in deserts. 7.2 Deserts

46. Wind Erosion 7.3 Landscapes Shaped by Wind  Wind erodes in the desert in two ways. 1. Deflation is the lifting and removal of loose particles such as clay and silt. It produces 2. Abrasion blowouts desert pavement—a layer of coarse pebbles and gravel created when wind removed the finer material

47. Desert Deflation

48. Wind Deposits 7.3 Landscapes Shaped by Wind  The wind can create landforms when it deposits its sediments, especially in deserts and along coasts. Both layers of loess and sand dunes are landscape features deposited by the wind.  Loess Deposits of windblown silt Extensive blanket deposits Primary sources are deserts and glacial stratified drift.

49. Wind Deposits 7.3 Landscapes Shaped by Wind  Sand Dunes Unlike deposits of loess, which form blanket- like layers over broad areas, winds commonly deposit sand in mounds or ridges called dunes. Characteristic features - Slip face is the leeward slope of the dune - Cross beds are the sloping layers of sand in the dune.

50. A Dune in New Mexico’s White Sands National Monument

51. Cross Beds Are Part of Navajo Sandstone in Zion National Park, Utah.

52. Wind Deposits 7.3 Landscapes Shaped by Wind  Types of Sand Dunes What form sand dunes assume depends on the wind direction and speed, how much sand is available, and the amount of vegetation. - Barchan dunes - Transverse dunes - Longitudinal dunes - Star dunes - Parabolic dunes - Barchanoid dunes

53. Types of Sand Dunes