Plate tectonics Rocky cycle, minerals, volcanoes, & earthquakes

1. Plate tectonicsRocky cycle, minerals, volcanoes, & earthquakes Integrated Science

2. Minerals can be identified by their properties • A mineral is a naturally occurring, solid substance made up of a single element or compound. • Examples Halite (table salt), copper, gold, and silver. • All minerals are inorganic—they are never formed by living or once living things. • Minerals have crystalline structures that reflect the orderly arrangement of their atoms.

3. Minerals can be identified by their properties • Geologists classify minerals into different groups. • The classification is based upon their chemical composition (which elements are present) and their crystalline structure (how the elements are arranged). • It is often easy to identify and classify minerals by observing their physical properties, (crystal form, hardness, cleavage, luster, color, streak, and specific gravity).

4. Minerals can be identified by their properties • Crystal Form • The orderly arrangement of atoms in a crystal • Fool’s gold (iron pyrite) you can see the cubes, quartz has 6 sided prisms that end in a point, asbestos is in threadlike fibers, hematite has globular shapes that looks like grapes • Well shaped crystals are rare in nature because the crystals must grow in cramped spaces.

5. Minerals can be identified by their properties Iron Pyrite Hematite

6. Minerals can be identified by their properties • Sometimes two or more minerals come from the same elements in the same proportions but they are arranged differently, these are called polymorphs. • Graphite and Diamond are polymorphs made of carbon, because of the different arrangement both have vastly different properties. • The formation depends upon the particular temperatures and pressures, this makes them good indictors of the geologic conditions at their formation sites.

7. Minerals can be identified by their properties

8. Minerals can be identified by their properties • Hardness is the Resistance of a Mineral to Scratching • Diamonds can scratch glass because it is harder than the glass. • The harder mineral will always scratch the softer one. • Hardness depends on the strength of a minerals’ chemical bonds—the stronger the bonds the harder the mineral

10. Minerals can be identified by their properties • Factors that influence bond strength are ionic charge, atom or ion size, and packing. • Strong bonds generally occur between charge ions (ionic bonding) the greater the attraction the stronger the bond. • Size affects strength because small atoms and ions can generally pack closer together than large atoms and ions. • Closely packed atoms and ions have a smaller distance between them and are attracted to each other with more force. • Gold with large atoms is soft, while diamond with small carbon atoms is hard.

11. Minerals can be identified by their properties • Cleavage and Fracture are ways in which minerals break • Cleavage is the property of a mineral to break along planes of weakness (determined by crystal structure and chemical bond strength) • Muscovite (mica) has perfect cleavage in one direction, it will break into thin sheets • Calcite has cleavage in 3 directions, it breaks to form rhombohedral faces. • Garnet has no cleavage (strong bonds in all directions)

12. Mica Calcite

13. Minerals can be identified by their properties • Fracture is when a mineral breaks but not along a cleavage plane. • A fracture that is smooth and curved so that it resembles broken glass is called conchoidal. • Most minerals fracture irregularly.

14. Minerals can be identified by their properties • Luster of a mineral is the way its surface when it reflects light • Minerals of the same color may have different lusters, and minerals of the same luster may different colors.

15. Mineral Lusters Adamantine - very gemmy crystals Dull - just a non-reflective surface of any kind Earthy - the look of dirt or dried mud Fibrous - the look of fibers Greasy - the look of grease Gumdrop - the look a sucked on hard candy Metallic - the look of metals Pearly - the look of a pearl Pitchy - the look of tar Resinous - the look of resins such as dried glue or chewing gum Silky - the look of silk, similar to fibrous but more compact Submetallic - a poor metallic luster, opaque but reflecting little light Vitreous - the most common luster, it simply means the look of glass Waxy - the look of wax

16. Minerals can be identified by their properties • A minerals color is easily observable feature, it is not very reliable means of identification. • Some minerals such as copper and turquoise have a distinct color. • The majority of minerals can be occur in a variety of colors or can be colorless. • Chemical impurities can affect a mineral’s color • The mineral corundum gives us red rubies or blue sapphires depending upon the impurities in it.

17. Minerals can be identified by their properties • Streak is the name given to the color of a mineral in its powdered form. • This is a very important characteristic of identifying minerals have a metallic or semimetallic luster. • The streak test- when rubbed across an unglazed porcelain plate, all minerals leave behind a thin layer of powder—a streak. • The streak of a mineral is always the same color, no matter the color variance of the mineral • A white streak (nonmetallic luster)cannot be used to identify minerals.

18. Minerals can be identified by their properties • Specific Gravity • Density = Mass / Volume (how heavy a mineral feels for its size) • Specific Gravity = Density of mineral / Density of Water • Gold has specific gravity of 19.3 This allows miners to pan for gold.

19. Minerals can be identified by their properties • Chemical Properties • Two simple tests are the taste test and the acid test (fizz test—Carbon dioxide CO2) • The taste test is used to identify halite (common table salt) Do not taste test minerals some are poisonous!! • Carbonate minerals will fizz when dilute (low concentrations) of hydrochloric acid (HCl) are place on them

20. On the way to Rocks • Rocks are made of many different minerals • Minerals are formed from the process of crystallization (growth of a material whose atoms come together in a specific chemical composition and crystalline arrangements) • Crystallization of minerals comes from 2 different sources magma (igneous rock) and water solutions (sedimentary rock)

21. On the way to Rocks • Melting point and Freezing point are the same temp! • Minerals melt at about 750oC to 1000oC • The Earth’s temp increases about 30oC for every km. • When minerals & rock melt new magma is produced, when magma cools minerals form and new rock is produced.

22. On the way to Rocks • Partial melting occurs because rocks are made of many minerals. The lower melting point minerals melt first. • If the whole rock melts the magma has the same chemical composition as the original rock. • Because of the different minerals that end up in the magma it then will cool into different rock types.

23. On the way to Rocks • Crystallization also occurs in water solutions. • Chemical sediments are formed when minerals precipitate form water in they were dissolved. • There are 2 categories: carbonates and evaporites • Limestone is the most abundant carbonate rock, it forms when organisms with shells die they accumulate at the bottom of the sea floor, through compaction over time limestone forms. • Cave dripstones (stalactites & stalagmites) also form from precipitating sediment from dripping water • Evaporites are formed when a restricted body of salty lake water evaporates. Gypsum and halite are form this way.

25. Rocks are divided into 3 Main Groups • Many rocks are either created, changed, or destroyed at plate boundaries. • Igneous rock formed by the cooling and crystallization of hot molten rock called magma. (Igneous means formed by fire) • Igneous rock makes up 95% of the Earth’s crust, Basalt and Granite are common igneous rocks.

26. Rocks are divided into 3 Main Groups • Sedimentary rocksare formed from pieces of other rocks (sediments) carried by water, wind, or ice. Sedimentary rocks are the most common rocks in the uppermost part of the Earth’s crust. • In fact sedimentary rocks cover more than 2/3 of the Earth’s surface, Sandstone, shale and limestone are common sedimentary rocks

27. Rocks are divided into 3 Main Groups • Metamorphic rockare formed from older pre-existing rocks (igneous, sedimentary, or metamorphic) that are transformed by high temperature, high pressure, or both WITHOUT melting. • The word metamorphic means “changed in form” • Marble and slate are common metamorphic rocks.

28. Rocks are divided into 3 Main Groups • Igneous rock forms when magma cools • Most of the continents are made of granite • Basalt is the most common on ocean floors • Extrusive (means pushed out of)igneous rock forms at the surface of the Earth • Partial melting and crystallization produce a variety of magma types (different amounts of silicon they contain) • The higher the silicon content the magma flows more slowly. • Temperature also affects the ability to flow of magma

29. Rocks are divided into 3 Main Groups • Magma on the surface is called lava • Lava can come from cracks and fractures in the Earth’s surface or volcanoes. • Most fissure eruptions occur when fast-flowing basaltic lava erupts at the bottom of the ocean forming the ocean floor.

30. Volcanoes come in a Variety of Shapes and sizes • All volcanoes are basically vents or holes where magma can rise to the Earth’s surface • Shield volcanoes have gently sloping cones that resemble a shield • They are built from many lava flows that pour out in all directions to cool as thin, gently sloping sheets • Some of the largest volcanoes in the world are shield volcanoes • Mauna Loa in Hawaii stands 4145 meters (13,599 ft) above sea level and more than 6750 meters (22,146 ft) above the deep ocean floor

31. Volcanoes come in a Variety of Shapes and sizes • Cinder cones

32. Earthquakes Make Seismic Wave • All earthquakes create waves that travel through the Earth’s interior. • Earthquake generated waves are called seismic waves. The way these waves travel provides scientists with a view into the Earth’s interior. • The major layers of the Earth the crust, mantle, outer core, and inner core. • A wave’s speed depends on the medium through which it travels. Example Sound waves travels faster through water than through air.

33. Earthquakes Make Seismic Wave • The speed of seismic waves depends upon the elasticity of the material through which they are traveling • Energy is released in an earthquake and radiates in all directions. This energy travels to the surface in the form of seismic waves. • Seismic waves cause the ground to shake and move. This movement is recorded on a machine called a seismograph.

35. Animations for Plate tectonics • http://education.sdsc.edu/optiputer/teachers/oceanfloordynamics.html

36. Types of Plate Boundaries & Landforms

38. Sedimentary Rocks • 2 kinds of weathering produce sediment • Mechanical weathering physically breaks rocks into sediments • Chemical weathering consists of chemical reactions that involve water and decompose rock into smaller pieces. • As rock is weathered it erodes (which means it is transported by water, wind, or ice)

39. Sedimentary Rocks • Clastic sediment is small fragments of other rocks (are usually very jagged until they are transported and break when they collide with other rocks or fragments) • Chemical sediment is produced by chemical means • Glaciers usually deposit poorly sorted sediments while wind is usually very well sorted and fine grained.

40. Sedimentary Rocks • In sedimentation, sediment particles are deposited one layer at a time it then becomes rock thru compaction and cementation • Minerals dissolved in water is what acts as the cement that bonds the sediments together • Iron oxide will produce red or orange rocks

41. Limestone is formed by the precipitation of calcium carbonate

43. http://www.uwgb.edu/dutchs/PLANETS/earth.htm

44. Overview of Earth Systems • The three main components of the Earth are the atmosphere, its gaseous envelope, the hydrosphere, the surface coating of water, and of course, the solid earth. All three are subdivided into subsystems. The atmosphere and hydrosphere get their energy mostly from the Sun, and the solid earth gets its energy from internal heat, some of which is produced by radioactive decay and some is left over from the formation of the earth. A tiny amount of energy also comes from gravitational interactions between the Earth, the Moon, and the Sun.

45. Convection is the transportation of heat by moving hot or cold material from place to place. Convection works because warm material is light and rises, while cool material is denser and sinks. As long as there is a temperature difference with depth, there will be a cycle of rising and sinking material. A lava lamp is a perfect illustration of convection - if geophysicists, astronomers, and other scientists who teach about convection had their way, lava lamps would never go out of style.

46. In reality, there is a continuous cycle. Material at the base of the mantle becomes hot and rises. As it rises, it expands and cools, and near the surface, heat leaks through the crust and escapes. Cooled mantle material begins sinking and descends to the bottom of the mantle, to be heated again.