Chapter 1 - Planet & Population Flashcards
What does Environmental Geology focus on?
The many interactions between humans and the geologic environment.
How old is the solar system?
12 to 14 billion years old
How was the solar system formed?
It formed as dust condensed from the gaseous nebula, then clumped together to make planets.
How do the compositions of the planets vary?
Higher metal and rock content in the 4 planets closest to the sun, and larger proportions of gas and ice in the planets further from the sun.
What is ACCRETION?
When gravity collects solid material that has been condensed from a solar nebula.
What are Earths major compositional zones?
The central core, the surrounding mantle, and the crust.
How old is the Earth?
4 billion years old
Mercury’s composition and physical properties.
Rocky, iron-rich, dry and pockmarked with craters.
Mars’ composition and physical properties
Shares surface features with Earth (volcanoes, canyons , dunes, slumps, stream Chanel’s, etc), but its surface is now dry and barren.
Jupiter’s composition and physical properties
It is a huge gas ball, with no solid surface, and has dozens of moons made out of ice and rock that circles it. It mimics that of a miniature solar system.
What does the core consist of?
Mostly iron; outer part is molten.
What does the mantle (largest zone) consist of?
Primarily ferromagnesian silicates, at great depth oxides of iron, magnesium, and silicon.
What does the crust consist of?
Oceanic crust (sea floor) is similar to the mantle, but is richer in silicon. Continental crust is thicker and less dense - it is rich in calcium, sodium, potassium, and aluminum.
The heating and differentiation of the early earth led to…
The creation of the atmosphere and oceans.
How did the ocean form?
Through the heating of minerals that contained water or gases, as the earth cooled the water and gas was able to condense to form the oceans.
What did the early earth’s atmosphere probably consist of?
Nitrogen and carbon dioxide released from volcanoes.
What is the “geologic spiral”?
A geologic record where important plant and animal groups are placed according to they’re first appearance in large quantities.
How did the earth become safe for oxygen-breathing organisms?
A single-celled blue-green algae appeared in large quantities, they manufactured food through photosynthesis, consumed carbon dioxide and released oxygen as a by-product.
Why do we not have solid record of how early creatures looked like?
They left very few remains as they had no skeletons, teeth, shells or other hard parts that could be preserved in rocks.
When did the first multicelled oxygen-breathing creatures first develop?
1 billion years ago
When did marine animals with shells become widespread?
550 million years ago.
How old is the rock with oldest evidence of animals with a backbone?
500 million years old.
When did insect appear?
300 million years ago.
When did land plants develop?
400 million years ago.
