PLEASE ANSWER ALL OF THESE QUESTIONS AND FOLLOW THE GUIDELINES Rocks and Mineral
ID: 119240 • Letter: P
Question
PLEASE ANSWER ALL OF THESE QUESTIONS AND FOLLOW THE GUIDELINES
Rocks and Minerals Unit Journal Assignment
It is now time to submit your journal entries from this unit. You should have the following entries in your journal from your work in this unit:
1)Crinoid Fossils: How do you think they got from the ocean floor to the mountains?
2)Neighborhood Rocks
Guideline: In your journal, describe some of the rocks around Pennsylvania. Describe some of their properties, such as how they look, the minerals that you think are in them, their texture and feel, and any other distinguishing features. Discuss whether or not any of the rocks you find look like those you have learned about so far in this unit.
3)Metamorphism
Guideline: In your journal describe what you learn about the word metamorphic. Also, describe how the term metamorphic as it applies to rocks is similar to the term metamorphosis as it applies to living organisms such as butterflies.
4)Structural Properties
Guideline:
One of the most fundamental laws of geology is that sedimentary rock layers are laid down horizontally, one layer evenly over the previous layer. But in this picture you see layers of rock that are now warped and folded and thrust upward into a vertical orientation. How do you think the layers got that way?
To help you answer that question, gather three or four towels of the same size. Place them horizontally on a table, one towel on top of the other. Then, with a hand at each end of the pile of towels, push inward on the towels so that they crumple together in the middle. Imagine the towels represent horizontal rock layers. What types of forces on Earth could make them become pressed together, compressed, and crumpled?
Explanation / Answer
1. Crinoid Fossils can be found in mountains while they live in ocean because the places of mountains(today) were once were the oceans in the past (millions of years ago) and hence we see these Crinoid Fossils in mountains today.
2. Majority of the rocks around Pennsylvania are from Paleozoic Era and are sedimentary in nature while the southeast portion of the state have igneous and metamorphic rocks in general. Example are: Shale, claystone and sandstone are three sedimentary rocks that can be found in pretty much every region of Pennsylvania apart from this Anthracite coal, granite, pegmatite, Rhyolite and Hornfels can also be found.
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.
Claystone is a fine grained siliciclastic sedimentary rocks.
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) mineral particles or rock fragments. Most sandstone is composed of quartz or feldspar because they are the most resistant minerals to weathering processes at the Earth's surface.
Anthracite is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal except for graphite.
Granite is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be predominantly white, pink, or gray in color, depending on their mineralogy.
A pegmatite is a holocrystalline, intrusive igneous rock composed of interlocking phaneritic crystals usually larger than 2.5 cm in size (1 inch).
Rhyolite is an igneous, volcanic rock, of felsic (silica-rich) composition. It may have any texture from glassy to aphanitic to porphyritic.
Hornfels is the group designation for a series of contact metamorphic rocks that have been baked and indurated by the heat of intrusive igneous masses and have been rendered massive, hard, splintery, and in some cases exceedingly tough and durable.
3. Metamorphism means the change in physical and chemical properties of a mineral and thus a rock(aggregate of mineral) due by temperature, pressure and chemically active solution.
Metamorphism is the process of transforming from one form to other in animals and so does it happen in rocks for example shale a sedimentary rock can convert in slate, schist, phyllite depending upon the grade of metamorphism.
4. The compressional forces that is acting up on the rock or the intrusion of any body from the below can cause this type of folding. Apart from this if the rocks are not ductile and is brittle then faulting will take place instead of folding.
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