Geology: Rock Cycle and Land Processes

Opening Prayer

• Presented as a prayer
• Included phrases like "Have Mercy on us" and "We trust in you"
• Requests hearts to be "like unto yours"
• Ends with "AMEN"

Prerequisite Knowledge

• The topic is "Prerequisite Knowledge"
• The listed values are service, honesty, integrity, nationalism, excellence

Rock Cycle and Geologic Processes

• The topic is "Rock Cycle and Geologic Processes"

Plate Motion

• Plate motions cause mountains to rise where plates push together (converge)
• Continents fracture and oceans form where plates pull apart (diverge)
• Continental drift is the movement of continents over millions of years

Continent Accretion Theory

• The continents have always been stationary (not moving).
• New material is constantly added around a central nucleus.
• Proposed by James Dwight Dana

Continental Assimilation Hypothesis

• Ocean areas collected denser elements that were then subsided to form basins.

Expanding Earth Hypothesis

• Present continents split apart due to Earth's expansion
• Combined continents could cover half of Earth's current surface area.

Continental Drift Theory

• Continents once existed as a single landmass called Pangaea
• Proposed by Alfred Wegener

Pangaea

• The supercontinent that existed before the current continents
• Covered by one big ocean called Panthalassa
• Divided into two landmasses by the Tethys Sea (Laurentia/Laurasia to north; Gondwanaland to south)
• 200mya (Mesozoic era, Triassic period, Late Triassic epoch)

Evidence for Continental Drift Theory

• Continental Shorelines fit together like puzzle pieces (evidence 1)
• Distribution of glacial sediments (evidence 2)
• Paleoclimate (evidence 3) shows similar deposits
• Distributions of fossils and their matching similarities (evidence 4) support one supercontinent
• Distribution of rocks and rock layers (evidence 5)

Evidence 1: The Fit of Continental Shorelines

• A map displaying the fitting together of the continents

Evidence 2: The Distribution of Glacial Sediments

• Image showing glacial scratch evidence

Evidence 3: Paleoclimate Data

• Map showing glacial striations

Evidence 4: Distributions of Fossils

• Map showing the distribution of various fossils (Cynognathus, Lystrosaurus, Mesosaurus, Glossopteris)

Evidence 5: Distribution of Rocks

• Map showcasing ancient rock formations and continental shelves

Sea-Floor Spreading

• A geological process where tectonic plates split apart
• Result of mantle convection
• Occurs at divergent plate boundaries
• Formation of mid-ocean ridges (large mountain ranges) arise from the ocean floor
• Harry Hess studied Wegener's theory in 1960
• Sonar is a device that detects the distance of objects under water using sound waves, part of sea-floor spreading studies

Mid-Ocean Ridge

• Longest chain of mountains in the world
• Divergent plate boundaries

Subduction

• Ocean floor sinks beneath a deep-ocean trench and back into the mantle.
• Part of the ocean floor sinks back into the mantle

Plate Tectonics

• Theory that Earth's outer shell is divided into plates that glide over the mantle
• Plates are strong, rigid shell compared to the mantle
• The strong outer layer called lithosphere is 100 km thick
• Lithosphere includes crust and outer part of the mantle
• Below the lithosphere is the asthenosphere which is malleable, enabling lithosphere movement

Plate Movements (Seven Major Plates):

• African Plate
• Antarctic Plate
• Eurasian Plate
• Australian Plate
• North American Plate
• Pacific Plate
• South American Plate

Plate Movements (Largest Minor Plates):

• Arabian Plate
• Caribbean Plate
• Cocos Plate
• Juan de Fuca Plate
• Nazca Plate
• Philippine Plate
• Scotia Plate

Group Activity

• Students will be divided into 6 groups.
• Each group will choose one continental drift theory evidence to explain.
• Groups will have 10 minutes to prepare.