What's most important: Understanding how geologists can use geologic rules to learn more about and understand the natural world. Connecting material from class to rock types, environments and features which can be seen in the natural world. Allowing your own curiosity and exploration of the world to reinforcing the lecture material.
Geology at the introductory level is really best learned and experienced in the outdoors. In contrast to the outdoor classroom, the majority of modern geologic work is often mostly completed in office buildings on computers. Although seeing geology in person allows a rich experience, doing field geology from the computer is not only possible, in some case (such as our exploration of Mars) computer driven field geology is our only current option. Furthermore, virtual geologists can view geology from a close up roadside view, and within seconds (depending on the internet speed) see the same location form a birds eye view.
1) Answer all of the questions throughout the trip
2) 1 big cross section and rough topo profile of California, and some arrows pointing to where some rock types can be found
3) 1 drawing and description of deformed sedimentary rocks
4) 1 drawing and description of deformed igneous rocks
5) 2 "how to think like a field geologist" descriptions at different stop sites.
Torrey Pines, state park: Stop #1 Torrey Pines
We are right along the coast in California's Torrey Pines state park. Take a look at the rocks visible in the area, I encourage you to move around and look around as you move.
How to think like a field geologist:
As you look at geology try to think about what rock types are there (start with the big classes of rocks, and try to narrow it down to a rock name if you can).
Once you have an idea of the rock type, try to think about where they came from, and how they formed. What type of environment did they need to form? How long did it take it to form? After their formation, think forward: Are they still forming today? Have they moved from where they were formed? What might have moved them, and what evidence of this move is left? What has happened to them since they formed? What will happen to them in the future?.
Next look at location of the rocks currently. Think about how the rocks will influence this environment (its climate, weather, and biology), and how the different aspects of the environment will influence the geology under it.
Now that you have an idea of what might be happening here, return to looking at the rocks. Does what you see in the rocks still fit in with your ideas? Sometimes geologists need to cycle though this process multiple times to come to a complete idea, and its during this processes that they test their ideas by looking for additional evidence that will prove them correct or incorrect.
Before you leave the area, take notes on what you have seen, and jot down a rough idea of what you think is happening here. These notes can be mini maps, words, paragraphs, pictures, drawings etc.
[1] Use the "how to think like a field geologist" approach to tell me about the rocks here.
[2] Determine which way the rocks are dipping (and estimate the angle if you can). Record this information by drawing some strike and dips on the map.
Stop #2 road cut on the 152 near San Luis Reservoir
California can be roughly broken down into 4 mountain groups, the coast ranges (North South and Transverse Ranges), the Sierra Nevada, The Peninsular Ranges (San Diego), and the Klamath Mountains (up by Oregon). The Coast ranges are broadly similar in geology, and most of it looks like our first stop, or like this stop. Look closely at the color of these rocks, and how they are broken.
[3] Describe these rocks as best you can from street view.
[4] What type of rock might we guess these are.
[5] What can we conclude about California's coastal ranges? (Be sure to talk your ideas over with me so I can make sure you are on the right track)
Stop #3 road cut on the 14 near Palmdale
Explore the rocks on the east and west side. You will want to go back and forth along the road cut.
[6] Broadly, what features do you see?
[7] Describe the features on the west side of the road (Easiest from the north bound side).
[8] Can you distinguish two appearances of rocks? Sedimentary rocks and fault gouge?
Your actually right on top of the San Andreas fault! Take a look at the area from the sky and see if you can identify where the fault is based on features on the ground. Stop #3 view from the sky
[9] What direction does the fault trend in this area (Using cardinal directions, like NE is fine)
Yosemite: The bulk of the Sierras is composed of granite. Yosemite is a granite valley carved by glaciers. This is what it looks like inside the valley: Stop #4 Yosemite
Take a look around.
[10] What do you mostly see?
[11] how would you describe the topography from this point of view?
Also a side comment, if you look at a lot of these 360 view pictures there is a common feature in them, typically a woman standing alone with a bored look on their face. We probably owe many thank yous to their patience!
Now for a quick trail run up the side of the canyon: Stop #5 Yosemite canyon side
[12] From this vantage point have your ideas on the topography changed?
[13] How would you describe the breaks in the rock on the far side of the valley?
Now a quick jump over to Halfdome: Stop #6 Half Dome
[14] From this vantage point have your ideas on the topography changed?
[15] Try to get a good look at the rocks here, what type of rocks are they?
[16] Describe the weathering happening on Halfdome:
Sonora pass winds over the Sierras north of Yosemite Tioga Pass. Here is what most of it looks like: Stop #7 Sonora pass
We are here however because of something that we don't find over in Yosemite: Stop #8 Giants
This stop has some good close-ups of the rocks: Stop #9 Giants close up
There are some more good 360 views on this website, as well as some explanation of how they form. Virtual field trip with more links
[17] What type of rocks are these?
[18] Describe how these types of rocks form.
[18] Think about the steps and history involved in these rocks. What does this tell us about what would have been above this rock?
[19] And would we find any Granite?
Eastern Sierras As we push further eastward along the mountain range it increase in elevation we start seeing a diffrent landscape that looks like the following: Stop #10 Sierras landscape
[20] What is the most drastic change you notice?
[21] Have the types of rocks changed here?
[22] What has directly caused the change in appearance?
[23] What geologically has influenced what you identified as the main factor in question 21?
Now onto the peak: This is Mount Whitney, named after Josiah Whitney, an 1800s geologist. Ironically Whitney did not believe that Yosemite and the Sierras were carved by glaciers, but from Whitney peak we can see a number of "U" shaped valleys in the cliff faces surrounding it. Stop #11 Mount Whitney Stop #11 A few feet from the other stop #11
[24] Contrast the rocks at the top of Mount Whitney with those on top of halfdome.
[24a] What is similar about them?
[24b] What is different about them?
Down the hill. These are the Alabama hills: Stop #12 Alabama hills 1
Stop #12 Alabama hills 2
Stop #12 Alabama hills 3
Notice in the last picture how rough looking the rock surface looks. This is actually granite as well.
[25] Contrast the rocks here with those on top of Mount Whitney and halfdome.
Owens river gorge is a good example of what a river cut valley looks like. Stop #13 Bishop tuff
[26] How would you describe the shape of the river valley?
Take a look at the pink looking rock on the opposite canyon wall, it is Bishop tuff: Stop #13 in the valley
Convict Lake: is stop 14: Stop #14 Convict lake
[27] Based on the valley shape, how did this lake and valley form?
Another hint is visible from above: Stop #14 Convict lake from above
Behind convict lake is Lauren Mountain: Stop #15 Laurel Mountain
[28a] What is a good guess for the rocks which make up Laurel Mountain?
[28b] Be sure to say WHY you think this.
Volcanoes around crater mountain: Stop #16 Crater Mountian
[29] How many volcano spots do you think you see?
Zoom in on the top most crater, Panum crater to take a look at it from the sky.
This is on the outside rim of the volcano: Stop #17 Panaum Crater
Stop #18 in the middle of the crater
[30] Describe the color of the rocks here
[31] What type of volcano could this be?
Devils post pile:
The post pile is located in a valley that mostly looks like this: Stop #19 post pile region
The post pile itself looks like this: Stop #20 Devils post pile side
And here is the top of the post pile: Stop #21 Post tile top
[32] What type of rock is the postpile made out of?
[33] What is another stop on the field trip that is similar to this one?
[34] How could you test to see if these two stops were formed from the same rock?
[35] Do you notice anything peculiar about the top of the post pile rocks? Describe it.
[36] What does this peculiar texture indicate?
As hopefully this field trip has indicated, road cuts are a fantastic place to find and see geology. To touch a few more aspects of this class I have one last set of stops. I encourage you to test your new field geology brain. Take a look at each of the three stops, and think up what the story is that this road cut tells. Then go over the questions and see if they point out something else that you missed, or if you have a good handle on field geology.
Stop #22
Stop #23
Stop #24
[36] Start with the rocks. What types of rocks do you see here?
[37] Describe how the rocks are arranged and if they are dipping.
[38] Identify the geologic feature here (there has to be some reason why I made us stop here) be sure to give the full name.
[38] Take a guess on the angle that this feature is dipping down, and roughly what direction.
[39] Draw a quick sketch of the area.
[40] If you missed it, find the igneous rocks along the road cut. How would we describe how they are arranged?
[41] Which rocks present are the strongest? (Hint look away from the road cut at the surrounding hillsides. Trace back a strong layer to your roadcut.)