Earth Interior and Rock Cycle PDF

Preview

Summary

Lab for geography...

Description

Lab Practice: Earth Interior and Rock Cycle Name: Lilly K.

Student ID:1647763

Score:

Use the figure Inferred Properties of Earth’s Interior to answer Question 1

/30 pnts

1. Use the chart on Page 1 to finish Table 1 Properties of Earth’s Interior Layers. Table 1: Properties of Earth’s Interior Layers Layer

Crust

Depth

Density (g/cm3)

5-70 km Oceanic • 5–10 km under Ocean • More than 5 times thicker Contine under ntal Continents

3.0

Uppermost Rigid Mantle

35-70km from Earth’s surface

Granitic 3.0 ______ 3.4

Pressure range (million atm.)

Phase / Texture

Basaltic

2.7

Asthenosphere 70km – 660km (plastic mantle) from Earth’s surface Lower Stiffer Mantle

Composition Temp. range

Olivine, Silicate minerals Olivine, Iron/ Magnesium Silicates

Air temp. to Air 1000 °C pressure to (1832°F) 0.1 million (increase atm. with depth)

Solid; Rigid

1000C ———— 2500C

0.1-0.2 million atm

Partially molten; Plastic

2500C ———— 5000C

0.2-1.5 million atm

Solid; Stiff

660 Km ——————— 2950 Km

3.4 ______ 5.6

Outer Core

2950Km —————— 5100Km

9.9 ——— 12.8

Molten Iron and Nickel

5000C ———— 6300C

1.503.0 million atm

Molten

Inner Core

5100Km ——————— 6500Km

12.8 —— 13.1

Solid Iron and Nickel

6300C ———— 6700C

3.0-3.6 million atm

Solid

a) According to Table 1, what happens to the density and temperature of rock within Earth’s interior as depth increases? Density and temperature of tock pithing earth’s interior increase as the depth increases.

b) The inferred temperature at the interface between the stiffer mantle and the asthenosphere is close to _2500_____ °C. The stiffer mantle has a higher temperature than the asthenosphere, but why it is stiff but upper asthenosphere is partially molten? Because the pressure and temperature in the atmosphere are very high, they cause the rocks to partially melt

c) The inferred temperature at the interface between the inner core and the outer core is close to 6300______ °C. The inner core has a higher temperature than the outer core, but why the inner core is solid but the outer core is molten? While the pressure density in the inner core is high enough to make it solid the pressure in the outer core isn’t high enough to make it solid 2. Read the following paragraphs: To understand the spatial variations of landforms and landscape-forming processes at the earth’s surface (i.e. Geomorphology), it is necessary to become familiar with the basic geologic materials that are found at (or near) the surface. A mineral is a naturally occurring chemical compound, usually of crystalline form and abiogenic in origin. The term rock is defined as an aggregate of minerals. There are numerous possible combinations of minerals that produce a large degree of variety in the rocks that are found in nature. For our purposes, however, we can classify rocks into a few select groups (igneous, sedimentary, and metamorphic) and discuss how rocks can provide evidence about the past history of earth. Part 1. Igneous Rocks Igneous rocks are formed as minerals crystallize directly from a molten (liquid) state. Igneous rock can be identified by looking at the color (determined by composition: felsic vs mafic) and texture (determined by cooling environment: extrusive vs intrusive)

Go to the website: https://geology.com/rocks/igneous-rocks.shtml and find the igneous rocks samples needed to answer the following questions a) Granite and Rhyolite has similar mineral composition – both are composed primarily of feldspar and quartz. However, the samples you saw have distinctly different appearances. Describe the texture (i.e. size of crystals) of Granite and Rhyolite samples. The texture of granite is coarse and non-vesicular which means there are no gas pocket. The size of the crystal is 10mm. While the texture of Rhyolite is fine with crystal sizes less than 1mm, the vesicular Rhyolite, which means there are gas pockets in the Rock is also there

b) Briefly explain why granite and rhyolite have different texture.

Granite and rhyolite have different texture because one of them is intrusive (granite) and the other one is extrusive (rhyolite

c) Now explore the samples of Basalt and Gabbro. Based on the texture of Basalt and Gabbro, match them to the correct category: Basalt: _______Extrusive__________________ Gabbro:______Intrusive________________________ d) How are basalt and gabbro different from granite and rhyolite in terms of color? Explain why.

Gabbro and basalt are different from granite and rhyolite in terms of color because they are just more mafic. Granite and rhyolite are more felsic

Part 2. Sedimentary Rocks. Sedimentary rocks form through the accumulation and consolidation of materials at (or near) the surface of the earth. Two important mechanisms by which this occurs are (1) clastic – whereby fragments of preexisting rocks accumulate and are cemented together; and (2) chemical/organic – whereby soluble materials such as calcium carbonate precipitate from a body of water and accumulate at the bottom.

Go to the website: https://geology.com/rocks/sedimentary-rocks.shtml to find the sedimentary rocks samples needed to answer the following questions: e) Compare the samples of conglomerate, sandstone, and shale. How they are different from each other in terms of grain-size? Sandstone is made of sand minerals and is 0.006 to 0.2 cm. Shale is a mix of clay minerals and has a grain size less than 0.0004cm. Conglomerate rocks are pebbles, cobbles and boulders embedded in sand, silt on clay. f) Study the sample of iron ore (https://geology.com/rocks/iron-ore.shtml ). Based on the description on the formation of iron ore, what kind of sedimentary rock it is? Clastic or Chemical?

It would be a chemical sedimentary which means it forms by minerals in precipitation

Part 3. Metamorphic Rocks Metamorphic rocks form as either igneous or sedimentary rocks are altered by the influence of heat and/or pressure. Such processes could occur beneath the surface as rocks are deeply buried or as they come into contact with hot liquid magma. Metamorphic rock can be roughly identified as foliated or non-foliated. Foliated metamorphic rocks are formed within the Earth's interior under high directed pressure. So you will see their appearance generally contains “stripes”. Non-Foliated metamorphic rocks do not have a striped appearance because they are formed around igneous intrusions where the temperatures are high but the pressures are relatively low and equal in all directions.

The first metamorphic rock sample to explore is Gneiss (as in have a “gneiss” day): https://geology.com/ rocks/gneiss.shtml . Its mineral composition is similar to that of granite and hence its coloring looks similar to granite. However, Gneiss is a metamorphic rock with distinct “banding” or alternating layers of light and dark minerals. g) What do you think is the reason for those “banding” to develop? What kind of environment does the banding indicate?

It is the result of changes in heat and air pressure. It is more of a structural change.

Marble (https://geology.com/rocks/marble.shtml ) is another metamorphic rock formed from limestone that is altered under high temperatures and or pressure. The resulting rock is much harder and more resistant to weathering than the original limestone from which it formed. In Shasta County (CA), which is to the south of volcanic mountain Mt Shasta, it is common to see gray limestone with marble occurred below. h) What do you think may be the reason for the presence of Marble near Mt Shasta?

It is because it’s close to volcanic mountain magma this heats up the limestone and created the formation of Marble.

Part 4. Rock Cycles 3. The figure below shows the rock cycle: any type of rock can become another one by certain processes. Match the vocabulary terms to the letters shown in the figure. Some terms may be used more than once.

i)

Melting C/I

l)

j)

Cooling and crystallization D

m) Heat and pressure B/H

k) Weathering, transportation and deposition G/F/E

Lithification A...