Earth Layers & Convection Currents
This is the thinnest, outermost layer of Earth that we live on
The Crust
The scientist who proposed the Theory of Continental Drift in 1912
Alfred Wegener
New ocean floor is continuously created at the underwater mountain chains
Mid-Ocean Ridges
This type of rock forms when magma or lava cools & hardens
Igneous Rock
The preserved remains or traces of ancient organisms found mostly in sedimentary rock
Fossils
The thickest layer of Earth, made of hot, semi-solid rock where convection currents flow
The Mantle
The name of the ancient supercontinent where all landmasses were joined together millions of years ago
Pangea
Seafloor spreading occurs at this type of plate boundary, where two plates pull apart
Divergent Boundary
This type of rock is formed from sediments that are pressed and cemented together over time, often containing layers
Sedimentary Rock
Ice & Amber
Convection currents occur because the hot material become less dense and rises, while the cooler material becomes denser and _________.
Sinks
This boundary type occurs where two tectonic plates slide past each other horizontally, often causing earthquakes
Transform Boundary
The oldest rock on the ocean floor is found farthest away from mid-ocean ridges near the deep features where subduction occurs
Ocean Trenches
Existing rocks that are changed by intense heat & extreme pressure turn into this type of rock
Metamorphic Rock
A fossilized footprint, burrow, or nest that shows evidence of animal activity rather than the organism itself
Trace Fossil
This layer of the Earth is liquid metal, mostly iron & nickel, and creates Earth's magnetic field
Outer Core
Mountains and deep ocean trenches are created at this type of plate boundary, where two plates collide
Convergent Boundary
The scienist who proposed the Theory of Seafloor Spreading
Henry Hess
The scale used to rank minerals based on their resistance to being scratched, from 1(Talc) to 10(Diamond)
A fossil of an organism that only lived for a short period of time & used by geologist to date rock layers
Index Fossils
The Lithosphere
Wegener's theory was rejected at first because he could not explain this crucial mechanism
How or why the continents move
The process where older, denser oceanic crust sinks beneath lighter crust back into the mantle
Subduction
The property tested by rubbing a mineral across a unglazed porcelain plate to oberve its color in powder form
Streak
According to this law, in undisturbed rock layers, the oldest layer is found at the bottom and the youngest layer is found at the top
Law of Superposition