Earth Systems 3209 Unit: 1 Introduction to Earth Science – The Evolution of Planet Earth Reference: Chapters 1, 17 and Appendix A & B

Earth’s Interior Focus on . . . Unit 1: Topic 2.4 recognizing that Earth (Geosphere) has a layered Interior. identifying the characteristics of each layer. drawing a diagram representing Earth's interior.

Earth’s Interior The model of Earth’s interior is based on indirect evidence. The diagram to the left outlines four main layers inside of Earth. Text Reference: pages 19-23 & 475-477

Layers of Earth’s Interior Lithosphere Lithosphere cool, rigid layer directly above the asthenosphere approximately 100 km thick, which includes the entire crust and a portion of the uppermost mantle

Layers of Earth’s Interior Crust Crust (two types) Continental Crust – 30 to 40 km thick and has low density Oceanic Crust – approximately 5 km thick and has high density

Layers of Earth’s Interior MOHO Mohorovicic Discontinuity (Moho) boundary separating the crust and the mantle distinguished by an increase in rock density velocity of seismic waves show an increase

Layers of Earth’s Interior Asthenosphere Asthenosphere (Upper Mantle) hot, weak zone of rock that is capable of gradual movement. This is the layer that the crustal plates rest upon located from approximately 100 km to 700 km in depth

Layers of Earth’s Interior Lower Mantle Lower Mantle consist of high density rocks rich in compounds of iron, magnesium, and silicon this layer is approximately 2200 km thick

Layers of Earth’s Interior Outer Core Outer Core consist of liquid iron and nickel approximately 2270 km thick seismic waves (S-waves) do not pass through this layer

Layers of Earth’s Interior Inner Core Inner Core consist of solid iron and nickel approximately 1216 km thick

Temperature and Density Increases with Depth Temperature inside Earth increases at a rate of approx. 35 degrees Celsius per kilometer. This is referred to as the Geothermal Gradient. Density inside Earth also increases as depth inside of Earth increases.

Example 1: Which layer of Earth’s structure is represented by “X” asthenosphere inner core lithosphere Outer core

Example 2: Which best describes continental crust? 7 kilometres thick; higher density than ocean crust 7 kilometres thick; lower density than ocean crust 35-40 kilometres thick; higher density than ocean crust 35-40 kilometres thick; lower density than ocean crust

Example 3: Which is the correct sequence of Earth’s layers from the surface to the center? Surface Center (A) crust - inner core - outer core – mantle (B) crust - mantle - outer core - inner core (C) mantle - crust - inner core - outer core (D) mantle - outer core - inner core - crust

Your Turn . . . Take the time and complete the following questions . . . (Solutions to follow) Questions: Draw a well labeled diagram outlining the layers of Earth.

Solutions . . . Labelled Diagram of Earth’s Layers:

Your Turn . . . Take the time and complete the following questions . . . (Solutions to follow) Questions: Reference the next slide and answer the questions on the bottom of the slide.

Your Turn . . . Q. 1 Label each of the layers in the diagram above. Density Relative Temperature Q. 1 Label each of the layers in the diagram above. Q. 2 Fill in the relative temperature as “HIGH” or “LOW”. Q. 3 Fill in the density as “HIGH” or “LOW”.

Solutions . . . 2.8 4.5 Questions: 9-10 13 Density Relative Temperature 2.8 4.5 9-10 13 Questions: LOW LOW HIGH HIGH

Fill in the following Chart at Home!! Inner Core Outer Core Lower Mantle Asthenosphere Crust Materials (Composition) State (s/l/g) Density Relative Temperature

Summary . . . Overview of Points covered: Earth’s layers include: Crust (Continental & Oceanic), Upper Mantle (Asthenosphere), Lower Mantle, Outer Core, Inner Core Temperature and Density both increase with depth inside of Earth