Chapter 1: Day 2: Evolution and Composition of Earth

Question 1

Geologic Time

Answer 1

Span of time since Earth’s formation

Question 2

Geologic Time Scale

Answer 2

Divides history of Earth into different units

Question 3

Nebular Theory

Answer 3

Solar system evolved from an enormous condensing, rotating cloud of gas and dust 5 billion years ago

Question 4

Nebular Theory made of?

Answer 4

Mostly hydrogen and helium

Question 5

Inner Planets Form?

Answer 5

Metallic and rocky clumps

Question 6

Outer Planets Form?

Answer 6

Fragments with a high percentage of ices

Question 7

Earth’s Spheres

Answer 7

The separate but interacting parts that affects our dynamic Earth

Question 8

4 of Earth’s Spheres

Answer 8

Hydrosphere, Atmosphere, Biosphere, Geosphere.

Question 9

Hydrosphere

Answer 9

Ocean the most prominent feature of the hydrosphere. Freshwater are streams, lakes, and glaciers, as well underground.

Question 10

Atmosphere

Answer 10

Thin, tenuous blanket of air. One half lies below 5.6 kilometers (3.5 miles)

Question 11

Biosphere

Answer 11

Includes all life. Concentrated near the surface in a zone that extends from the ocean floor upward for several kilometers into the atmosphere

Question 12

Geosphere

Answer 12

Solid Earth. Extends from surface to the center of the planet. Largest of Earth’s four spheres. Based on compositional differences, it consists of the crust, mantle, and core. Divisions of the outer portion are based on how materials behave

Question 13

Ocean basins

Answer 13

Average 3.8 kilometers (2.8 miles) below sea level. Basaltic rocks

Question 14

Continents

Answer 14

Flat features that average 0.8 kilometers (0.5 miles) in elevation. Granitic rocks.

Question 15

5 Major Features of Ocean Basins

Answer 15

Continental Margins, Deep-Ocean Basins, Oceanic Ridge, Mountain Belts, Stable Interior

Question 16

Continental Margins

Answer 16

Portions of seafloor adjacent to major landmasses

Question 17

Continental shelf

Answer 17

Gently sloping platform extending seaward from shore

Question 18

Continental slope

Answer 18

steep drop off at edge of continental shelf

Question 19

Continental rise

Answer 19

more gradual incline; continental slope merges with thick accumulation of sediments

Question 20

3 Deep-Ocean Basins

Answer 20

Between continental margins and oceanic ridges. Abyssal plains: flat features of deep-ocean basins. Deep-ocean trenches: deep depressions in ocean floor. Seamounts: submerged volcanic structures.

Question 21

3 things about Oceanic Ridge

Answer 21

Also called mid-ocean ridge
. Includes Mid-Atlantic Ridge and East Pacific Rise
. Continuous mountain belt that winds around globe
. Many layers of igneous rock

Question 22

Mountain Belts

Answer 22

Also called ring of fire:

Principally the circum-Pacific belt and the Alps/Himalayas

Question 23

Stable Interior

Answer 23

. Shields: expansive, flat regions of deformed crystalline rock.
. Stable platforms: deformed rocks covered by sedimentary rocks