Geology 200 Getting Started...

Transcription

1 Geology 200 Getting Started... Name This handout should be completed and become a part of your Notebook for this course. This handout is intended to be a review of some important ideas from your introductory geology course, but you may find that there are some new concepts for you. Please let me know if you have questions and need help completing this handout. We will use the rock record in each National Park to investigate the history of the region, therefore we need to recall how various types of rocks are classified, formed, and what this tells us about the environment of deposition. We will divide the class into three large groups. Each group will become "experts" on their type of rock. Here is a list of the basic rock types at you probably learned in introductory geology: Igneous Sedimentary Metamorphic andesite breccia gneiss basalt chert marble dacite coal phyllite diorite conglomerate quartzite gabbro limestone schist granite sandstone slate granodiorite shale obsidian siltstone rhyolite volcanic breccia Which rock group were you assigned? 1. Describe how one determines the names for the rocks in your rock group. (For example, if you are in the sedimentary group, how does one tell the difference between a sandstone and a conglomerate or a sandstone and a limestone?) You do not have to describe each rock, just the classification scheme and you should make a list of the rock types in each sub-group. (For example, in the igneous rocks, there are intrusive and extrusive sub-groupings under the igneous group). Let me know if you have questions! (There is more space for your answers on the next page!) 1

2 2. Once you go to your small group (with three to four people) follow the same format as the previous question for the other two major rock groups. (for example, if you your previous group was metamorphic rocks, the other people in your small group will tell you how to answer this question for the sedimentary and igneous rocks.) Again, if you have questions, please let me know. 2

3 3. How do we determine if a rock sample is granite or gabbro? 4. How do we determine if a rock sample is gneiss or quartzite? 5. How do we determine if a rock sample is chert or limstone? 6. How do we determine a rock sample is obsidian or basalt? 7. One of the major rock types at the bottom of the Grand Canyon (where the Colorado River flows today) is schist. What does the presence of this schist tell us about the history of the Grand Canyon region during the time the schist formed? 8. If we find that there are limestone layers in the upper part of the Grand Canyon, what does that tell us about the history of the Grand Canyon area during that period of time? 9. In your introductory course you probably learned some basic principles that help us determine the order (or relative ages) of geological events. If we see a sequence of layered rocks, the layer on the bottom is the. To answer this previous questions you used the Principle of. Which types of rocks do not obey the principle listed above? Why? 3

4 10. If we find that a series of layered rocks are tilted (folded), we assume that the folding came the rocks were formed. This principle is termed the Principle of. 11. In the photo to the right there is a fault that cuts from the upper right to the lower left. This fault must have happened the deposition of the layers. This principle is called: As a side note-- is the fault a normal or reverse fault? How can you tell? 12. We will complete a relative age sequence from a diagram on the screen during class. Enter the relative age history in the space below. 4

5 13. Discuss the various relative age principles you used in completing this sequence and give one example of each. If you have questions about the things we cover during class, you are probably not alone! Please let me know if you have questions! 5