Anyone who has traveled at all realizes that not all parts of the earth are the same
Both surface features and the rocks below the surface
It's also clear that the earth is not ever-present and unchanging
Lots of examples of small (and large) scale changes we can observe
Multnomah Falls rockfall
Yosemite Valley: Glacier Point rockfall, Merced River 1997 floods
Applegate River at Hwy. 199
There are 2 processes: Construction and Destruction
These examples are all destructive
Happen at a faster rate so we recognize them
The constructive processes are also exciting
Volcanoes, earthquakes
They also seem to happen fast, but...
Geology is the study of these surface and bedrock processes
What makes our earth
We tear it down in The Hydrosphere
Geologists need to be able to see the actual rocks
We're not all soil scientists!
Unfortunately, there's a lot of dirt! (Not to mention placed covered by water)
Look for places where the rock is exposed at the surface
Outcrops: Let's hear it for road cuts!
DIGRESS TO: bedrock vs. float
In any event, need to get all the dirt and biological contamination out of the way in order to adequately do our job
Not everyone gives geology much respect
Geology isn't a 'Fundamental Science'
Not like Physics, Chemistry, etc.
How many of you are here because of this?
We can't answer all of our questions by doing empirical experiments
Geology is a 'Multidisciplinary' science
This is a $.50 word which says that it draws strength from many different areas of scientific study
DIGRESS TO: don't freak out; just take big words apart
Geophysics, geochemistry, etc. (and math? I'll try to minimize the pain.)
Geology is also a field oriented science
The field IS our science!
Hope to have several field trips during the term
DIGRESS TO: who will be invited along
Possibility of top students joining my RCC trips
Earth has been here a long time
The study of geology gives us our only glimpse into the earth's past
This glimpse is admittedly biased, as we will come to learn throughout this course
I'm a real geologist
I love geology and being a geologist
The study of the earth is the best there is
And the job requirements aren't that tough (obviously)
What we do is pretty straight forward
Observe and record; and beat up rocks
It is traditional that geologists...
Camp out a lot and spend lots of time around a campfire
Have a realistic view of time and space, and are extremely well-adjusted
Are relatively unaffected by much of the normal day-to-day BS
And best of all, there are no real "laws" in geology
Not like the fundamental sciences which rely on 'natural laws' to help them make sense
And keep them boring and predictable
All we have are a few general guidelines to help clarify the mess
Some of our best follow...
Uniformitarianism - 'the present is the key to the past'
If a process is active today, it probably worked the same across geologic time
Gravity, water running downhill, that kind of thing
The concept of uniformitarianism states that there are natural laws that have worked continuously and unchangingly throughout geologic time
Careful here...
'Change' is the rule in geology (as it is in life)
I like to think that a strict uniformitarian view may be too restrictive
You'll find that I preach skepticism in this course
A geologic idea is much like a weather forecast - both are based of estimates of probability
A good geologist is rarely 100% sure
Beware modifiers such as: always, never, all, every, forever
All in all, though, uniformitarianism is a valid and needed concept
Law of Superposition
"...in any undisturbed sequence of layered rock any one layer will be older than the layer above it and younger than the layer below it"
The key term here is "undisturbed sequence of layered rock"
Commonly used to determine the relative ages of sedimentary rocks
Law of Original Horizontality
States that sedimentary beds are laid down horizontally (or near horizontally)
If they aren't flat, some tectonic force must have disturbed them
Define "tectonics"
There are definitely exceptions to this "law"
DIGRESS TO : regional vs. local
With rules like these to follow you can see that geologists have to use their imaginations
There are others which we will discuss at other times
Law of Cross-cutting Relationships
And the heavyweights!
Scientific experimentation is somewhat different between geology and the fundamental sciences
In physics and chemistry, the scientific method can be applied
Hypotheses and experimentation to prove (or disprove) the hypothesis
My version of the S.M. may be a bit different, and include a couple additional steps
Wild & Crazy Idea ---> Hypothesis ---> Theory ---> Law ---> Dogma ---> Stagnation
Click here for a more detailed discussion of my version of the scientific method
In geology, we really can't PROVE anything
No Universal Laws of Geology to form a firm foundation for experimentation
The complexity of the lab!
Also, many of the processes occur outside of our range of vision
Both spatial and temporal (space and time)
EXAMPLE: high grade metamorphics
SHOW: sedimentary --> migmatite samples
There is no black and white in geology - only infinite shades of grey
Nothing works in every possible situation (oops, there are those modifiers!)
Laboratory experiments are commonly inadequate in their attempts to duplicate natural processes
The earth is the most complex and well-equipped lab we know of
Impossible to duplicate in an artificial and controlled setting
So what do we really know for sure?
You need to keep an open mind when trying to study the earth
Helps to have several ideas going at the same time
Work to "rule out" as well as "prove"
And keep updating your "forecast!"
In geology, you can ask one question and get three more as an answer
Sometimes it doesn't seem fair
Put it all together and it seem pretty hopeless
Doesn't mean that we can kiss off the study of the earth
Geologists are trained to observe & record what they see in the natural world
These must be done well
It's the interpretation that is open to GeoFantasy