Geology

700 words. Location will be anywhere in Los Angeles area. You can pick.

Go outside! Take yourself on a field trip trip and look around for an example of a sedimentary rock. Describe in detail the features (texture, composition, sedimentary structures, fossils, etc.) of your rock and how you determined it was indeed sedimentary. Note also that preexisting igneous, metamorphic or sedimentary rocks may comprise part of the grain composition in your sedimentary rock of choice; per the concept of the rock cycle. Next, discuss how and in what type of depositional environment this rock may have formed. If at all possible, please submit at least one digital photo with your description in the initial post. Note: If you are having a difficult time finding a sedimentary rock because you live in a region dominated by igneous or metamorphic rocks, describe some local sediment instead, it is everywhere! Once you’ve completed your field trip, please post your detailed description, interpretation, and discussion to the discussion board. Please include a location as others may also want to check out your field site.

For Further Thought:

Geologic maps

If you are going to be serious about going for a hike – one will often visit the place first using a topographic map. Likewise, when searching for rocks, use a geologic map. A geologic map of bedrock or surficial rocks is divided up into colors that are symbolic of the ages of the rocks on the ground. Geologists make these maps and sometimes provide interpretive cross-sections of parts of the map. The colors typically follow geological and geomorphological patterns, often stopping at faults or other important contacts. Study the geographic area near you and then look at the key. The key or explanation gives you the age, lithology and location of the rocks. This is a great starting point for your quest for a good sedimentary rock.

Start with the site below if you live in WA, or at www.usgs.gov to find other locations:

• http://www.dnr.wa.gov/Publications/ger_geol_map_washington_pagesize.pdfThis is a PDF Geologic map of Washington State. There are also numerous other maps and resources on the Washington Division of Natural Resources web page.

Plenty of other more detailed local geologic maps or websites may help you to determine where sedimentary rocks occur locally and may help you later with the field trip for Assignment #6.

Note: You are not required to use a geologic map for your field trip on assignment #2. Because maps are a very useful resource, this information is provided as a reference.