Chapter 2 Flashcards
What is the primary significance of the habitable zone around a star
It can only be called a natural disaster if the impact has caused human casualties, extensive destruction of property, and significant economic loss
Age of the earth - reversals
Polarity of the earth changes during different ages of the Earth
Mineral
a naturally occurring, inorganic, crystalline solid with a definite chemical composition
Rocks
naturally occurring solid consisting of mineral grains
Intrusive Igneous Rock
made out of solidified magma
Extrusive Igneous Rock
made out of solidified lava
Sedimentary Rocks
composed of clasts that are eroded from a source area, transported by water, wind, or ice, and are deposited at the Earth’s surface and subsequently lithified
Metamorphic Rocks
transformed from an existing rock into a new type of rock due to high heat and pressure from within the Earth
What is the primary difference between a rock and a mineral?
A mineral has a definite chemical composition, while a rock is a composite of different minerals
Rock Cycle: Igneous
Igneous rocks form from cooled magma or lava
Rock Cycle: Weathering + Erosion
Breakdown of rocks into smaller particles by natural forces
Rock Cycle: Sedimentary Rocks
Formed from compacted and cemented sediments
Rock Cycle: Metamorphic Rocks
Formed from existing rocks under increased pressure and temp
Rock Cycle: Magma Formation
Rocks melt under high pressure to become magma again
Lithosphere
The rigid uppermost layer (“Plate”) of the earth. Includes the crust and uppermost layer of the mantle
Crust
- 15% less dense than the mantle
- oceanic crust: 7-10 km thick, silica poor
- continental crust: 25-70 km thick, silica rich
Alfred Wegener
- Proposed all continents were once connected and then drifted apart (named it Pangaea)
- Theory was initially rejected as he had no concrete evidence
Evidence for Plate Tectonics
Seafloor spreading explained the force behind moving plates and recycling of oceanic lithosphere and gave information unobtainable via studying continents
What is the role of the seafloor spreading played in the theory of plate tectonic theory
All of the above
How fast do tectonic plates move?
About the rate your fingernails grow, a few centimeters a year
Plate Boundaries
Divergent: away
Convergent: toward
Transform: horizontally (like cars on a street)
Age of the Earth
4.6 Ga or 4600 Ma
Ga: billions of years
Ma: millions of years
