1. Some Basic Geology Classes of Rocks

2. Igneous Formed by solidification of gaseous or molten material from cooling magma or lava More commonly seen in areas such as the Canadian Shield where bedrock from the Precambrian lies at the surface. Examples: basalt, obsidian, granite (cools more slowly), volcanic ash (tuffa, pumice)

3. Basalt

4. Basalt Columns Giant's Causeway - Ireland

5. Devil’s Tower, WY

6. Basalt Columns Keweenaw Peninsula Michigan

7. Basalt with Opal

8. Obsidian

9. Obsidian

10. Obsidian

11. Granite

12. Volcanic Ash (Tuff)

13. Volcanic Ash (Pumice)

14. Canadian Shield

16. Sedimentary Formed by compaction of material  Clastic rocks: older rock broken up by ice, wind, water (erosion) Shale, sandstone, clay  Organically/chemically produced rocks Limestone, chalk, coal – from living organisms Salt - chemical Gypsum - chemical

17. Limestone

18. Starfish in Illinois limestone

19. Thornton Quarry

20. Layers of sediment formed on a sloping portion of the Silurian reef.

21. Devonian Dolomite Silurian Limestone: which is older?

22. Dolomite from Joliet Dolomite cliff

25. Sandstone

26. Saint Peter Sandstone along Rock River

27. French Canyon at Starved Rock State Park. Also St. Peter sandstone.

28. Pictured Rocks National Lakeshore, Michigan Lake Superior

29. Puddingstone Type of sedimentary rock Michigan Puddingstone is a conglomerate of primarily quartzite and pebbles of jasper

30. Metamorphic Form when igneous or sedimentary rocks are changed by heat, pressure, or infiltration with other materials  Characteristics flaky: slate (comes from mud) non-flaky: marble (comes from limestone) sparkly: gneiss (comes from igneous or sedimentary rocks) Quartzite: comes from sandstone

31. Slate – metamorphic mud

32. Marble – metamorphic limestone

33. Metamorphic Granite Gneiss = sparkling

34. Quartzite – Metamorphic sandstone

35. Baraboo Quartzite, Wisconsin