Layers of the Earth
What is the name of the outermost, solid, rocky layer of the Earth upon which we live?
Crust
What term describes the large, moving sections of the Earth's lithosphere that fit together like pieces of a puzzle?
Tectonic plates
What classification of rock is formed when molten magma or lava cools and solidifies?
Igneous rock
What is the primary difference between weathering and erosion?
Weathering breaks down rocks into smaller pieces in place, while erosion transports those broken pieces away.
What does the Law of Superposition state about undisturbed sedimentary rock layers?
The oldest layer is at the bottom, and each higher layer is progressively younger.
Which semi-fluid, plastic-like layer of the upper mantle flows slowly and allows tectonic plates to float and move on top of it?
Asthenosphere
At what type of plate boundary do tectonic plates move away from each other, often forming mid-ocean ridges or rift valleys?
Divergent boundary
Processes like compaction and cementation of weathered mineral grains and organic debris lead to the formation of which rock type?
Sedimentary rock
Water seeps into cracks in a rock, freezes, expands, and splits the rock apart. What type of weathering is this?
Mechanical (or physical) weathering (specifically ice wedging).
What method determines whether a rock layer or fossil is older or younger than surrounding layers without giving an exact numerical age in years?
Relative dating
Which layer of the Earth is composed primarily of liquid iron and nickel and generates Earth's magnetic field through its swirling motion?
Outer core
What geological process occurs when a dense oceanic plate collides with a lighter continental plate and sinks into the mantle?
Subduction
Which geologic process transforms any existing rock (igneous, sedimentary, or another metamorphic rock) into a metamorphic rock?
Extreme heat and pressure deep underground (without completely melting the rock).
Acid rain reacts with minerals in limestone, causing caves and sinkholes to form over time. What type of weathering is this?
Chemical weathering
What are index fossils used for in relative dating?
To match (correlate) and date rock layers across different geographic locations because the organisms lived briefly and over a wide area.
Even though it is the hottest layer of the Earth (exceeding 5,000°C), why is the inner core solid rather than liquid?
Extreme gravitational pressure from all the overlying layers forces the atoms into a tightly packed solid state, raising the melting point.
What primary driving force within the Earth's mantle causes tectonic plates to move around the globe?
Convection currents (driven by heat from the Earth's core and lower mantle).
If an intrusive igneous rock is pushed deep into the Earth, melts completely into magma, and then slowly cools below the surface, what kind of rock does it become?
Another (new) igneous rock
Which agent of erosion is primarily responsible for carving out V-shaped river valleys and the Grand Canyon?
Moving water (rivers and streams)
What does an unconformity in a sequence of rock layers represent?
A gap in the geologic record where erosion occurred or deposition stopped for a long period, resulting in missing rock layers.
How does the mechanical lithosphere differ chemically and structurally from the asthenosphere directly beneath it?
The lithosphere is rigid and brittle (made up of the crust and uppermost mantle), while the asthenosphere is ductile and deforms plastically (like hot putty).
Which specific type of boundary is characterized by neither the creation nor the destruction of crust, but rather by intense earthquakes as plates grind past each other?
Transform boundary (e.g., San Andreas Fault)
Why is the rock cycle considered a "non-linear" system rather than a strict 1-to-2-to-3 sequence?
Any rock type can be transformed into any other rock type or recycled through alternative pathways depending on Earth's processes (e.g., sedimentary can melt directly into igneous, igneous can become metamorphic, etc.).
How would a hot, humid climate typically affect the rate of chemical weathering on exposed granite statues compared to a cold, dry desert climate?
It would be significantly faster because high temperatures and abundant moisture accelerate chemical reactions.
An igneous intrusion cuts vertically through three horizontal sedimentary layers (A, B, and C, with A on bottom and C on top). According to the Law of Cross-Cutting Relationships, what is the relative age of the igneous intrusion?
The igneous intrusion is younger than layers A, B, and C because the rock layers had to be there first in order to be cut through.