Module #9 - Rocks and Minerals
INSTRUCTIONS FOR TODAY
1. Watch the following videos:.
Video of the Day: Igneous Rock "Flipped Classroom" Lecture (20 minutes)
Video: Understanding the Rock Cycle (8 min.)
Be sure to make point form notes in your digital video journal. Please make sure that you SHARE your document with Mr. Durk.
2. Read the following information below in Part 1: Background and Terminology. Follow all hyper-links to external websites for activities, demonstrations and videos (if applicable). Copy only KEY information (i.e. the highlighted terms) to your digital notebook (in google docs). You may work with a partner to do this as there are quite a few key terms and concepts to get down.
3. Complete Part 2: Rock Cycle and Classification of Rocks and Minerals Assignment (see below) and complete during class time ideally.
DUE DATE: Before Module #10
Part 1: Background and Terminology
Please remember to record all definitions and content in your virtual notebook. Definitions can be found by clicking on highlighted words.
Thus far, we have observed the three main layers of the earth; core, mantle, and lithosphere or crust. For the remainder of this unit, we shall concentrate on the layer that affects us most and that we, in turn, affect most - the lithosphere. In this activity, we shall study the composition of the earth’s crust.
Types of Rocks and Classification
Rocks fit into one of three broad categories: igneous, sedimentary, or metamorphic, depending upon how they were formed. An igneous rock is solidified magma; a sedimentary rock is compacted, cemented mud, sand, or gravel; a metamorphic rock is an igneous or sedimentary rock that was buried at great depth and baked at high temperatures. Metamorphic rocks are sometimes folded as a result of deformation.
In order to classify a rock, it is necessary to take a very close look at it: first its general appearance and colour, then its grain size and texture. Each of these three types of rock are further categorized in the following rock classification chart.
Acknowledgements: Natural Resources Canada
Igneous
Igneous rocks form when molten rock (magma), originating from deep within the earth, solidifies. The chemical composition of the magma and its cooling rate determine the final igneous rock type.
Intrusive
(plutonic)
Extrusive
(volcanic)
Clastic
Chemical
Biologic
Foliated
Non-foliated
Intrusive igneous rocks are formed from magma that cools and solidifies deep beneath the earth’s surface. The insulating effect of the surrounding rock allows the magma to solidify very slowly. Slow cooling means the individual mineral grains have a long time to grow, so they grow to a relatively large size. Intrusive rocks have a characteristically coarse grain size.
Extrusive igneous rocks are formed from magma that cools and solidifies at or near the earth’s surface. Exposure to the relatively cool temperature of the atmosphere or water makes the erupted magma solidify very quickly. Rapid cooling means the individual mineral grains have only a short time to grow, so their final size is very tiny, or fine-grained. Sometimes the magma is quenched so rapidly that individual minerals have no time to grow. This is how volcanic glass forms.
Clastic sedimentary rocks are made up of pieces (clasts) of pre-existing rocks. Pieces of rock are loosened by weathering, then transported to some basin or depression where sediment is trapped. If the sediment is buried deeply, it becomes compacted and cemented, forming sedimentary rock.
Clastic sedimentary rocks may have particles ranging in size from microscopic clay to huge boulders. Their names are based on their grain size.
Chemical sedimentary rocks are formed by chemical precipitation. This process begins when water travelling through rock dissolves some of the minerals, carrying them away from their source. Eventually these minerals are redeposited when the water evaporates away or when the water becomes over-saturated.
Biologic sedimentary rocks form from once-living organisms. They may form from accumulated carbon-rich plant material or from deposits of animal shells.
Foliation forms when pressure squeezes the flat or elongate minerals within a rock so that they become aligned. These rocks develop a platy or sheet-like structure that reflects the direction that pressure was applied.
Non-foliated metamorphic rocks do not have a platy or sheet-like structure. There are several ways that non-foliated rocks can be produced. Some rocks, such as limestone, are made of minerals that are not flat or elongate. No matter how much pressure you apply, the grains will not align! Another type of metamorphism, contact metamorphism, occurs when hot igneous rock intrudes into some pre-existing rock. The pre-existing rock is essentially baked by the heat, changing the mineral structure of the rock without the addition of pressure.
Sedimentary
Sedimentary rocks are formed from pre-existing rocks or pieces of once-living organisms. They form from deposits that accumulate on the earth’s surface.
Metamorphic
Metamorphic rocks are rocks that have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot, mineral-rich fluids or, more commonly, some combination of these factors.
Acknowledgements:USGS
Rock Cycle
All the rocks at the earth's surface are slowly being altered and broken down. The particles produced by these processes are transported by water, wind, or gravity, and accumulate as sediments. After undergoing several physical and chemical changes, these sediments will eventually become sedimentary rocks. If a sedimentary rock is buried at great depth within the earth's crust, it will be transformed into a metamorphic rock. If a metamorphic rock is subjected to still higher temperatures, it may melt, forming a magma that will crystallize as an igneous rock. The cycle will then begin again. The cycle can also be interrupted or short-circuited as shown by this diagram representing the rock cycle.
Video: Rock Cycle Rap (Optional, but entertaining)
Resources
Part 2: Assignment: Classification of Rocks and Minerals - Chart
1. Complete the Online Rock Identification Lab with a partner if you'd like.
2. Complete the Scavenger Hunt of Geoman's Rock and Mineral Identification (Mr. Durk will provide a paper copy OR make a google document and table). You will need to use various sites to complete these tables.
3. Research ONE rock of your choice. On a separate google doc, create a one page summary / fact sheet about your rock of choice. You must include the following on your Fact Sheet: Where is it found? How is it formed? What type of rock is it? What is this rock used for by humans? Also, include at least 3 images of the rock itself and at least one link to a video or interesting article about that rock.
NOTE: You should be able to complete most of today's Module during class time. Good luck!
Useful Links
Geoman's Rock and Mineral Identification Site - Rocks