1. Mysterious rock formations…….

7. What could have caused these formations? GLACIERS!!!!!

8. Evidence for Glaciers  Erratics  Unsorted material  Striations  Polished Bedrock

9. Erratic

10. Erratic  Boulder-sized rock dumped by a glacier  Rock is different type than surrounding rocks

12. Unsorted Materials- all sizes mixed together.

13. Striations

14. Chatter marks (Maine)

15. Striations/ Chatter marks  Grooves carved into bedrock  Formed by abrasive action of cobbles and pebbles carried at bottom of glacier  Direction of scratches shows direction glacier moved

16. Glacial polish  Smooth rock surfaces  Created as glaciers flow over bedrock

17. Glacial Pavement….

18. What does a glacier look like?

19. What conditions are necessary for glacial formation?  Cold Summers!!  Located above the snow line, or in polar regions.  Presently occupy 10 % of world’s total land area (32% during ICE AGES)  Form on all continents BUT Australia

20. Process of Glacier Formation  Snow does NOT melt in summer  Recrystallization of snow to form LARGE crystals of ice (rough and granular) –called FIRN: liked packed snowballs  Lower layers turn to SOLID ICE under the weight of overlying firn and snow.

21. Snow becomes Firn

22.  Glaciers: Types  VALLEY GLACIERS:  long, slow-moving, wedge-shaped streams of ice  Bordered by mountains  Size varies*  small= 1-2 km long, 100’s m wide, 100’s m deep*  largest = Over 100km’s long X 100’s m deep

23.  CONTINENTAL GLACIER (ICE SHEETS):  very old (1000’s of years) and thick (1000’s of meters)  Not confined by mountains  Examples:  GREENLAND: 1.7 million square miles, 2 miles thick  ANTARCTICA: 12.5 million square miles, 3 miles thick

26. Features associated with valley (alpine) glaciers

27. Original valley (V-shaped) Glaciers come and alter landforms Glaciers retreat and new features appear

29. Landscape Features- Valley Glaciers  CIRQUES:  semi-circular shaped bedrock feature  created as a glacier scours back toward the mountain

30.  ARÊTES:  steep-sided, sharp-edged bedrock ridge  formed by two glaciers eroding away on opposite sides of a ridge

31. CIRQUE TARN TARNS: glacial lakes produced by glacial scouring often found in cirques

32.  HORNS:  3 or more cirques adjacent to one another

33. Hanging Valley

34. ARÊTE CIRQUE HANGING VALLEY U-SHAPED VALLEY

35. U-shaped valley

36. CONTINENTAL GLACIERS FEATURES

40. Lateral moraine

41.  MORAINES: material left behind when glacier recedes

42.  When glacier retreats (melts) rock and sediments are dropped behind  Long Island, Cape Cod and the islands are part of a terminal moraine

43. Kettle Lake Till Drumlins Terminal Moraine Glacial Stream Moraine-dammed lake Outwash plain Esker

44. Drumlin

45. drumlins

46. Kettle Lakes

47. River in glacier carries sediment Glacier melts Drops sediment Esker results

48. Eskers