Physical Geology Notes Ch. 1
Define and understand the branches of geology.
Explain the key steps used to study science.
Describe the formation of planets in the solar. system, including Earth.
Understand what makes Earth unique.
Explain the importance of time and change in geology.
The scientific study of Earth.
Understanding processes and materials.
Sequence of geologic events
Why did the dinosaurs suddenly die out 65 million years ago?
The way a scientist approaches a problem
Varies in detail
Includes five key steps
Not necessarily a linear methodology, though
Observations and data gathering
Hypothesis: a plausible, but not yet proven, explanation for how something happens
Theory: a hypothesis tested and supported by observation and experimentation
Formulating law/ theory
The system concept
Breaking large complex problems into smaller pieces without loosing sight of the connection.
Systems typically fall into two major categories:
The solid Earth, as a whole
All living and recently dead organisms
The gasses that surround Earth
Water and ice, both on the surface and underground
Zone where all known life exists
Found 10 kilometers above or below Earth’s surface
Describes the movement of water
Processes that form, modify, transport or break down rock
Processes that drive the movement and interactions in the lithosphere
The solar system
Earth is one of eight planets in orbit around the Sun
Also includes 140 moons, asteroids, comets meteoroids
The solar system coalesced out of a swirling cloud of interstellar dust/gas
Called a nebula.
Sun born from a nuclear reaction called fusion
Fusion combines hydrogen atoms to form helium
Outer portions of solar nebula cooled into disks of debris.
Random collisions formed clumps that eventually grew large enough to pull in remaining debris through gravity.
A fragment of extraterrestrial material that falls to Earth.
Violent collisions between planets and meteorites important aspect of planetary accretion
Differentiation: the layering of terrestrial planets based on chemical composition
Crust: outermost compositional layer
Thin, low-density and rocky
Mantle: middle layer of Earth
Rocky, intermediate density
Core: innermost layer
High density and metallic
Other planets in the solar system exhibit differentiation
Rich in oxygen
Contains water as solid, liquid or vapor
Full of living organisms
Blanket of loose debris covering Earth
The movement and interactions of large fragments of Earth’s lithosphere, called plates
Responsible for shaping continents and ocean basins, as well as distribution of volcanoes and earthquakes
Thinner, denser and younger, underlying the ocean basins
Relatively thin and comprised of basalt (igneous rock type)
Older, thicker, and less dense, the bulk of earth’s landmasses
Generally thick and comprised of granite (igneous rock type)
Unique to Earth
Earth is dynamic system
Proposed by James Hutton
The processes governing the Earth systems today have operated in a similar manner throughout geologic times
“the present is the key to the past”
Time and change
Physical processes on Earth have not changed , but the physical conditions on Earth have changed dramatically.
Earth is our home planet
We depend on Earth for all our material resources
Limited resources require knowledgeable and thoughtful management
Earth’s physical and chemical processes affect us
We need to appreciate our own role in geologic change
In what ways do geologic processes affect your daily life?
Name some examples of artificial systems. Are they closed or open systems?
If you were an astronomer studying young suns, what kind of evidence would you look for in order to test the nebular hypothesis?