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Earth Science
Chapter 1: Introduction to Earth Science
Pages 1-25.
Key Terms: Abyssal plain, asthenosphere, astronomy, atmosphere, biosphere, closed system, continental margin, continental
shelf, continental slope, core, crust, deep-ocean basin, deep-ocean trench, Earth science, Earth system science, environment,
geologic time scale, geology, geosphere, hydrosphere, hypothesis, inner core, interface, lithosphere, lithospheric plate, lower
mantle, mantle, meteorology, model, nebular hypothesis, negative feedback mechanism, nonrenewable resource, oceanic
(mid-ocean) ridge, oceanography, open system, outer core, paradigm, physical environment, plate tectonics, positive
feedback mechanism, renewable resource, seamount, shield, stable platform, system, theory
I.
II.
III.
General Earth Science
a. Earth Science is the name for all the sciences that collectively seek to understand Earth
and its neighbors in space.
i. Geology
1. Physical geology is the study of the materials & processes that operate
beneath & on Earth’s surface.
2. Historical geology is the study of the origin of the Earth and the
development of the planet.
ii. Oceanography is the study of all forms of water on Earth including oceans,
lakes, groundwater, etc.
iii. Meteorology is the study of the atmosphere & the processes that produce weather
& climate.
iv. Astronomy is the study of the universe.
b. Environment is everything that surrounds & influences an organism. Everything that is
nonliving is considered the physical environment.
c. Earth Science focuses on resources such as water, soil, metallic and nonmetallic minerals
and energy.
i. Renewable resources can be reproduced in a relatively short period of time, like
plants and animals, natural fibers and wood.
ii. Nonrenewable resources are resources that either don’t reproduce at all (like
metals) or take too long to reproduce to be reasonable (oil and natural gas).
d. Earth science also deals with environmental problems and hazards like earth quakes and
severe weather.
e. Earth science is measured in millions and billions of years, not decades or centuries. See
fig. 1.7, page 10.
Scientific Inquiry
a. Begins with a hypothesis or model—a tentative explanation that can be tested.
b. Scientific theories are well-tested and widely accepted views that the scientific
community agrees best explains certain observable facts.
c. A paradigm is a theory is extensively documented.
d. The scientific method is used for testing all hypotheses and theories.
Evolution of the Earth
a. Nebular Hypothesis
i. Proposes that the bodies of the solar system evolved from a rotating cloud called
the solar nebula.
ii. Inner planets (Mercury, Venus, Earth, Mars) had relatively high temperatures and
weak gravitational fields, thus unable to accumulate lighter gasses in the nebular
cloud.
IV.
V.
VI.
iii. Outer planets (Jupiter, Saturn, Uranus, Neptune) had low temperatures and weak
fields so they attracted more ice and light gasses.
Earth’s Spheres
a. Hydrosphere refers to all of the water on the planet, from the oceans to the atmosphere
to the precipitate.
b. Atmosphere refers to all of the gas enveloping the planet. It is relatively thin compared
to the other spheres.
c. Biosphere contains all biological life.
d. Geosphere extends from the surface to the center of the planet and refers to all nonliving
components (and non-water, non-atmospheric) of the Earth.
Structure of the Earth
a. See fig. 1.13 on page 16.
b. Crust
i. Oceanic Crust is about 7km thick and composed of basalt.
ii. Continental Crust is anywhere from 40km to 70km thick and is composed
primarily of granitic rock (granodiorite).
c. Mantle
i. Upper Mantle
1. Composed mostly of peridotite.
2. Top portion is the lithosphere.
a. Consists of upper mantle & crust and forms the Earth’s cool outer
shell.
3. Bottom portion is the asthenosphere.
a. Weak layer that the lithosphere can move independently of.
ii. Lower Mantle
1. Hot, high-pressure region that is capable of flowing gradually.
d. Core
i. Outer Core
1. Liquid layer that generates the earth’s magnetic field (caused by the
movement of the molten iron).
ii. Inner Core
1. Solid due to immense pressure.
e. Continental Drift & Plate Tectonics
i. See fig. 1.15 page 17.
ii. Continental drift is the idea that the continents move about the face of the planet.
iii. Plate Tectonics
1. The outer shell is broken into lithospheric plates that are in continual
motion.
Earth’s Outer Face
a. Continental Features
i. Mountain Belts
ii. The Stable Interior
1. Shields
a. Expansive flat regions composed of deformed crystalline rock.
2. Stable Platforms
a. Flat areas in which highly deformed rocks are covered by a thin
coating of sedimentary rocks.
b. Oceanic Features
i. Continental Margins
VII.
1. Portion of the seafloor adjacent to major landmasses.
a. Continental Shelf
i. Gently sloping platform of material extending seaward
from the shore. A flooded extension of the continents.
b. Continental Slope
i. Relatively steep dropoff that extends from the outer edge of
the shelf to the ocean.
c. Continental Rise
i. Thick accumulation of sediments that moved downslope
from the continental shelf to the deep-ocean floor.
ii. Deep-Ocean Basins
1. Between the continental margins and oceanic ridges.
a. Abyssal plains
i. Flat features in the deep-ocean basins.
b. Deep-Ocean Trenches
i. Deep depressions that are occasionally more than 11,000m.
c. Seamounts
i. Submerged volcanic structures along the ocean floor.
iii. Oceanic or Mid-Ocean Ridge
1. Layer upon layer of fractured igneous rock that has been uplifted.
2. Forms a continuous belt that winds around the globe.
Earth Systems Science
a. A system can be any size group of interacting parts that form a complex whole.
i. In a closed system, no matter enters or leaves the system.
ii. In an open system, both energy and matter flow in and out of the system.
b. Earth System Science aims to study Earth as a system composed of numerous
subsystems.
c. Feedback Mechanisms
i. Negative Feedback Mechanisms work to maintain the system as it is.
ii. Positive Feedback Mechanisms drive and encourage change.
d. A common Earth System is the hydrologic cycle.
i. See fig. 1.12 page 23.