1. Agenda Jan. 29, 2013 Mr. King 1.Rock Powerpoint – take notes 2.Assignment #15: Rock or Mineral Lab 3.Fossil Vocabulary 4.Homework: #19 Fossil Vocabulary Flash Cards

2. ROCKS TYPES OF ROCKS AND THE ROCK CYCLE

3. Rocks or Mineral? Rocks No definite composition Can have organic parts No definite properties Classified by how formed Minerals Definite composition Inorganic – no living remains Definite properties Classified by composition and crystal shape

4. TYPES OF ROCKS Unlike minerals, rocks cannot be classified by their properties Rocks are classified by HOW they formed TEXTURE tells the pressure & temperature; COMPOSITION tells where formed:  Igneous: Melting & Cooling  Sedimentary: Compacting & Cementing  Metamorphic: Heat & Pressure

5. IGNEOUS ROCKS Rocks that have been MELTED and COOLED magma: molten rock below earth’s surface lava: molten rock above earth’s surface

6. IGNEOUS ROCKS MELTED & COOLED Classified by HOW FAST and WHERE they cool: Intrusive rocks - cooled INSIDE the earth Cooling takes a LONG time because the earth insulates the heat; Slow cooling time means LARGE crystals Extrusive rocks - cooled OUTSIDE the earth’s crust They are cooled quickly and form SMALL crystals

7. IGNEOUS ROCKS MELTED & COOLED Granite Intrusive Large grains

8. * makes up new ocean floor Basalt* Extrusive Small grains * makes up new ocean floor Gases released near the surface of a lava flow create bubbles or that are “frozen” in stone IGNEOUS ROCKS MELTED & COOLED

9. Pumice Extrusive - Small grains IGNEOUS ROCKS MELTED & COOLED

10. Obsidian Extrusive Small grains - glassy Snowflake IGNEOUS ROCKS MELTED & COOLED

11. IGNEOUS ROCKS Summary When magma (melted rock) cools & crystallizes underground crystals grow large, and the rock is called GRANITE. HOT MAGMA When magma breaks through a weak part of the earth's crust the rock is called LAVA. Crystals are too small to see because volcanic rocks cool quickly. Examples: BASALT, SCORPIA, TUFF, PUMICE, and OBSIDIAN

12. SEDIMENTARY ROCKS Formed by COMPACTION & CEMENTATION Composed of layers of sediments Process : 1.Weathering: breaking down of rock at the Earth’s surface (mechanical or chemical) producing Sediments (rock fragments, sand, mud) 2.Erosion: transportation of weathered rock pieces 3.Deposition: eroded particles settle (often in layers) 4.Compaction: pressure applied squeezes out water 5.Cementation: fills in the gaps and “glues” rock

13. SEDIMENTARY ROCKS COMPACTED & CEMENTED How to recognize sedimentary rocks: Composed of various rock fragments Composed of layers (strata) Can contain fossils Crumble easily

14. CONGLOMERATES form in stream beds and pebble beaches SEDIMENTARY ROCKS COMPACTED & CEMENTED

15. SANDSTONE made up of fine-grained particles, has a sandy texture (feels gritty) Sandstones form in sandy environments such as beaches, sand bars, deltas and dunes SEDIMENTARY ROCKS COMPACTED & CEMENTED

16. LIMESTONE – chemical weathering SEDIMENTARY ROCKS COMPACTED & CEMENTED

17. SEDIMENTARY ROCKS Summary Sedimentary Rocks, like sandstone, shale, & limestone are made from PIECES that were buried COMPRESSED) & CEMENTED together.

18. METAMORPHIC ROCKS Rocks changed by heat and pressure NO MELTING Recrystallization: the crystals of old rock reform into new crystals and sometimes new minerals Occurs below earth’s surface, usually between plates Foliated (distinct layers of flatten minerals) vs. Nonfoliated (no layers)

19. SLATE - foliated Uses include roofing, fireplaces, and “blackboards”. METAMORPHIC ROCKS PRESSURE & HEAT Parallel planes. Gray, black, green or red.

20. METAMORPHIC ROCKS PRESSURE & HEAT GNEISS – foliated Black and white banding Banding is “squiggly” because heat makes the rock “plastic (flexible)”

21. METAMORPHIC ROCKS Summary METAMORPHIC ROCKS have been CHANGED because of HEAT & PRESSURE Sedimentary Rocks Igneous Rocks Metamorphic Rocks

22. Conglomerate THE ROCK CYCLE The Story of METACONGLOMERATE Once was a SEDAMENTARY conglomerate..... It was subjected to high temperatures and pressure; The pebbles squished and elongated to form layers (foliated) Kept pebbly appearance It became a metamorphosed conglomerate, and received a new name: metaconglomerate.

23. THE ROCK CYCLE The Story of Marble Once was a SEDAMENTARY limestone..... It was subjected to high temperatures and pressure; The layers were flattened and twisted It became a metamorphosed limestone, and received a new name: marble. People polished it and used it in their homes as tiles. Some marble was even carved into statues! limestone

24. Shale Metamorphosis of Shale to Gneiss From Sedimentary to Metamorphic SHALE is the most common sedimentary rock. Through pressure and heat, (metamorphism), it changes into other rocks. These changes take place without melting the rock! Increasing Temperature and Pressure Slate Phyllite Schist Gneiss SHALE becomes SLATE SLATE becomes PHYLLITE PHYLLITE becomes SCHIST SCHIST becomes GNEISS

25. Metamorphosis of Gneiss to Granite When gneiss melts and cools, it becomes granite! Gneiss Granite From Metamorphic to Igneous!

26. THE ROCK CYCLE Series of changes that “recycle” rocks from one type to another A model that sums up the formation, breakdown, and reformation of rock

27. Assignment #15: Rock or Mineral Lab

28. Fossil Vocabulary (p. 30) Law of Superposition: Top layer is the youngest in undisturbed layers of rocks Strata/Stratified/Stratification: Layer of rocks Fossils: Remain or trace of living thing Index Fossil: Fossil remains of organism that lived a very brief time – often found in only one layer of rock Mass Extinction: Disappearance of large number of species over short time

29. Fossil Vocabulary Cont. Relative Time: Time compared to another time; younger or older than _____ Resident Time: Time an element occupies a place Absolute Time: Exact time – usually AD or BC are specified Geologic Time Scale: Outline of major events in Earth’s history – based upon mass extinction periods

30. Homework: #19 Fossil Vocabulary Flash Cards