II.A Minerals and Rocks

Core Subject: Earth and Life Science

II. Earth Materials and Processes
A. Minerals and Rocks

The learners
demonstrate an
understanding of:
1. the three main categories of rocks
2. the origin and environment of formation of common minerals and rocks

The learners:
1. identify common rock-forming minerals using their physical and chemical properties
2. classify rocks into igneous, sedimentary, and metamorphic

1. II. EARTH MATERIAL AND PROCESSES M I N E R A L S a nd R O C K S

2. Minerals and Rocks are the significant building blocks of our dynamic earth. make up the solid part of lithosphere and provide us with valuable resources. Over 5,000 minerals but only few occur as rock-forming minerals.

3. Igneous Rock Sedimentary Rocks Metamorphic Rocks 3 Main Categories of Rocks:

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5. from a Latin word “ ignis ” which means fire . The parent material of igneous rocks is usually magma ( a molten material from deep within the earth that cools and hardens ). Igneous Rocks

6. . Its an exothermic process ( heat is liberated ) and involves a change of phase from liquid to solid state . generally hard and tough Igneous Rocks

7. Texture  relates to the general appearance of an Igneous Rock. Varieties of Igneous rocks

8. , 1) Fine-grained Igneous rock ( “ Aphanitic ” )  has smaller crystal due to the faster rate of cooling of the magma. 2) Coarse-grained Igneous Rock (“ Phaneritic ”)  has larger crystal due to the slower rate of cooling of the magma. Varieties of Igneous rocks

9. Varieties of Igneous rocks B. Composition  refers to the elements in the magma that directly affect the kind of mineral that is formed when the magma cools.

10. Mafic – are magmas associated with crystal spreading . Felsic – are magmas associated with crystal compression . Varieties of Igneous rocks

11. A. INTRUSIVE IGNEOUS ROCKS cool slowly forms coarse grained rock presence of crystal growth B. EXTRUSIVE IGNEOUS ROCKS cool quickly forms fine-grained rock. lack of crystal growth Types of Igneous rocks

12. This are magmas that rise and flow into the cracks in the crust but do not reach the surface. They harden deep inside the crust . A . Igneous Intrusive or Plutonic Igneous

13. . It takes thousands or even millions of years to solidify. usually coarse-grained with large crystals often form the core of mountains or volcanoes. A . Igneous Intrusive or Plutonic Igneous

14. Texture: light-colored  igneous rock  with large grains Composition: quartz and  feldspar   with minor amounts of mica, amphiboles, and other minerals.  Granite

15. Texture: coarse-grained , dark-colored, intrusive  igneous rock. Composition: composed mainly of the minerals plagioclase and augite . Gabbro

16. Texture: coarse-grained   igneous rocks Composition: granite  and  basalt . Diorite

17. Texture: fine-grained , extrusive igneous rocks that are usually light to dark gray in color . Composition: plagioclase feldspar and may contain  biotite , p yroxene , or amphibole. Andesite

18. This are magmas erupt onto the surface from volcanoes called lava . It’s a cooled lava at the surface of the earth . B. Igneous Extrusive or Volcanic Igneous

19. , Make the soil in the surrounding areas fertile . Cools faster and solidifies quickly if exposed in atmosphere or into the water. Have small crystals that gives fine-grained texture . B. Igneous Extrusive or Volcanic Igneous

20. Most common examples of igneous extrusive 1 . Basalt -A mafic silicate rock usually dark-colored, hard find-grained with high specific gravity. 2. Obsidian -Its dark-colored but glassy so it has no crystal.

21. i 3. Pumice -have many air holes because gas bubbles are trapped in the rock during cooling process. -its light color with low density that why it floats in water. 4. Scoria -same as pumice. Has larger holes and more denser and darker.

22. SENDIMENTARY ROCKS Form from “lithification”, a process of sementing soft, unconsolidated sendiments into hard rocks. Deposition is the process when rocks are fragmented into tiny bits, then carried to low areas and settled at the bottom. Sedimentation is the process of building up of deposited rocks after many years.

23. Stages in the Formation of Sedimentary Rocks

24. 3 main types of sedimentary rocks 1 . Classic Sedimentary Rocks -mechanical weathering that involves the breakdown of rocks into smaller ones at the surface of the crust, piled on top of one another and “lithified”.

25. dc 2. Chemical Sedimentary Rocks - when dissolved materials precipitate. Precipitation is separation of solid substance from a liquid. 3. Organic Sedimentary Rocks - formed by accumulated sedimentary debris caused by organic processes.

26. Common examples of sedimentary rocks 1. Conglomorate - a rock made up of pebbles, pieces of gravels cemented together. 2. Sandstones - made of grains mainly composed of mineral quartz.

27. h 3. Shale -made from layers of mad and chemical mixed with finesand, organic matter, iron oxide and other impurities. Its soft and smooth rock that easily breaks to into layers. 4. Limestone - made up of calcium carbonate. Came from dead organism.

28. Metamorphic Rocks The metamorphic rocks get their name from ”meta” (changed) and “morph” (form).Movement of earth causes rock to be pressed or buried that leads to an increase in temperature and pressure. This causes physical and chemical changes in the original rock-prolith. Metamorphism is the transformation of the rock’s minerology and physical characteristics.

29. Types of Metamorphic Rocks

30. Type of Metamorphic Rocks A. Non-foliated Metamorphic Rocks -rocks that are formed around the igneous intrusive. -their atoms recognize while becoming more compact and dense. -shows color bands that reflects very small impurities.

31. Examples of Non-Foliated Metamorphic Rocks 1 . Marble - derived from limestone-its parent rock. - a hard crystalline rock and the most beautiful rock because of its shimmering luster. 2. Quartzite - derived from sandstone, its hard and durable - is not always white. Some contains iron oxide thus, they appear reddish.

32. B. Foliated Metamorphic Rocks These are metamorphic rocks formed within the earths interior. Extremely high temperature and unequal pressure. Better identified on the basis of their texture.

33. Examples of Foliated Metamorphic Rocks 1. Slate -derived from shale. A fine-grained rock. Made of menirals quartz and muscovite along with hematite, biotite and pyrite. 2. Serpentine -used for both mineral and metamorphic rock. It originates from basalt.

34. . 3. Gneiss -derived from conglomerate. Contains of feldspar or quartz. Coarse-grained texture, making the layered bands of alternating minerals highly visible.

35. Types of Metamorphism Contact (thermal)metamorphism -evolves when rock near igneous intrusive gets heated. -produces non-foliated metamorphic rocks. Regional metamorphism (pressure) -affects a large area due to mountain formation. -foliated rocks are produced and strong pressure effects.

36. Rock Cycle The transformational processes that change rocks from one kind to another.

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