Unit 2: Study Guide

What is a mineral? How are minerals formed?

• A mineral is a naturally occurring usually inorganic solid that has a definite crystalline structure and chemical composition.

• Minerals are formed: – As magma and lava cool– By metamorphism– From solutions

What is an element?

• Elements are pure substances that cannot be broken down into simpler substances by ordinary chemical means

What is a compound?

• A substance made up of atoms or ions of two or more different elements joined by chemical bonds.

What is the difference between silicate and nonsilicate minerals?

• Silicate minerals contain silicon and oxygen, normally in the form of silicate tetrahedrons.

• Nonsilicate minerals do not.

What are the different properties that can be used to identify minerals? Define each

property.• Color- color of the mineral• Streak- color of the powdered form of the mineral.

(Remember: that if a scientist draws on a white tile with the mineral, this is how the streak is found.)

• Luster- way a surface reflects light• Cleavage and Fracture- The way the mineral breaks/splits• Density- measure of how much matter in a given amount of

space.• Hardness- mineral’s resistance to being scratched.• Special Properties- any property specific to the mineral

Know the three different rock types: What are they? How are they each created?

• Igneous rock forms when magma or lava cools and hardens

• Sedimentary rock forms from compressed or cemented layers of sediment.

• Metamorphic rock forms from other rocks as a result of intense heat, pressure, or chemical processes.

What is weathering?

• Weathering is the natural process by which atmospheric and environmental agents, such as wind, rain, and temperature changes, disintegrate and decompose rocks.

What is erosion?

• Erosion is the process by which wind, water, ice, or gravity moves soil and sediment from one location to another.

What is deposition?

• Deposition is the process in which material is laid down.

What is the rock cycle?

• The rock cycle is the series of processes in which rock forms, changes from one type to another, is destroyed, and forms again by geologic processes.

• Look in your book on page 78 for a diagram of the rock cycle.

What is uplift?

• Uplift is the rising of regions of Earth’s crust to higher elevations.

What is subsidence?

• Subsidence is the sinking of regions of the Earth’s crust to lower elevations.

What is a rift zone?

• A rift zone is an area of deep cracks that forms between two tectonic plates that are pulling away from each other.

What are Earth’s compositional layers?(Make sure you can label them)

Crust

Mantle

Core

What is convection? Where does convection take place in Earth and why is it important?

• Convection is the movement of matter due to differences in density that are caused by temperature variations; can result in a transfer of energy as heat.

• Convection takes place in the Earth’s mantle.• Convection helps rocks move slowing in the

mantle. (Cooler rocks sink and warmer rocks rise)

What are the Earth’s physical layers?(Make sure you can label them)

Lithosphere

Asthenosphere

Mesosphere

Outer CoreInner Core

What is Pangaea? Why is the idea of Pangaea important in understanding Earth’s history?

• Scientists think that about 245 million years ago the continents were joined in a single large landmass that they call Pangaea.

• It’s important to understand that at one time scientists think that all the continents were connected and during millions of years the continents moved into their current locations.

What is sea-floor spreading?

• Sea-floor spreading is the process by which new oceanic lithosphere sea floor forms when magma rises to Earth’s surface at mid-ocean ridges and solidifies, as older existing sea floor moves away from the ridge.

– Older rock- far from ridge– Newer rock- formed near ridge

Theory of plate tectonics

• This theory explains how large pieces of the lithosphere, called plates, move and change shape.

What is a tectonic plate?

• A tectonic plate is a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle.

Different plate boundaries(Know the arrow diagrams!)

• Convergent- Two plates collide.

• Divergent- Two plates move away from each other

• Transform- Two plates move past each other horizontally

What are the three different mechanisms that cause tectonic plates to move?

• Mantle Convection

• Ridge Push

• Slab Pull

What is an anticline?(Look on Page 107 for a diagram)

• Anticlines- oldest layers of rock are in the middle of the fold. The youngest rocks are towards the outside.

Anticlines are shaped like a: n

What is a syncline?(Look on Page 107 for a diagram)

• In syncline folds the youngest rocks are in the middle and the older rocks are on the outside edges.

Synclines are shaped like a: u

Faults

• Strike-Slip Faults– Formed when rocks are under shear stress and at

transform boundaries• Normal Faults– Formed when rocks undergo tension and at

divergent boundaries• Reverse Faults– Formed when rocks undergo compression and at

convergent boundaries

Faults

• Be able to label a diagram of each fault, with where the hanging wall, footwall and fault plane are! (Look on page 109)

Three types of mountains

• Folded Mountains- Form when rock layers are squeezed together and pushed upward. – Usually at convergent boundaries

• Volcanic Mountains- Form when melted rock erupts onto Earth’s surface

• Fault-Block Mountains- Form when tension makes the lithosphere break into many normal faults. Along the faults, pieces of the lithosphere drop down compared with other pieces. The pieces left standing form fault-block mountains.

What is an earthquake?

• Earthquakes are ground movements that occur when blocks of rock in Earth move suddenly and release energy.

• Label #6 page 116 in your book.– Know that the Focus is the point underneath the

Earth– The Fault Line is the line between both of the plates– The Epicenter is on the Earth’s surface.

Label a volcano

• Label #5 on page 126 in your book. – Know this!– Know magma is underneath the Earth & lava is

when it has reached the Earth’s surface

Three types of volcanoes

• Shield Volcanoes- Broad base, gently sloping sides, and form from mild eruptions.

• Cinder Cones- Steep volcano formed from violent eruptions

• Composite Volcanoes- Alternates between mild and violent eruptions.

Where do volcanoes occur?

• Divergent boundaries

• Convergent boundaries

• Hot Spots