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This project will have you analyze a rock as a way to apply some of the learning that you have achieved over the semester

Geography

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This project will have you analyze a rock as a way to apply some of the learning that you have achieved over the semester.  Successful completion of this project will ensure that you have met two of the student learning outcomes for our course:

1. Describe the materials that make-up solid Earth and processes that shape its surface features, and
2. Use physical and chemical data on minerals, fossils, and rocks to classify them, determine their ages, and explain their origins.
    

Preparation

Walk around (or hike) in your neighborhood or a nearby area and pick a large sedimentary rock whose size is at least the fist of your hand.

Make sure what you have picked is not man-made material such as a brick or concrete (hard material made by mixing Portland cement, water, and sand, gravel, or crushed stone). Also make sure that you do not use a mineral for this assignment. You have to use a natural rock.

If you can travel a short distance from campus, there are several places where sedimentary rocks are commonplace. Most of these are located in the coastal areas in southern California stretching from Malibu to Palos Verdes-San Pedro to Dana Point, to mention a few. If you happen to visit actual outcrops of sedimentary rocks, take at least one wide-angel view of the whole rock outcrop (you must also be in the picture.) plus several close-ups to show details of the rock.

NOTE: THE ROCK YOU WILL USE FOR THIS PROJECT MUST BE ONE THAT YOU PICKED FROM YOUR NEIGHBORHOOD OR NEARBY HIKING TRAIL OR COASTAL AREA. YOU CAN'T USE ROCKS ORDERED FROM AMAZON OR SHOPS/PERSONS THAT SELL ROCKS. ONE REASON THAT YOU ARE REQUIRED TO WRITE THE LOCATION WHERE YOU FOUND THE ROCK IS TO DISCOURAGE GETTING LABELLED/DESCRIBED ROCKS FROM ROCK SELLERS. IF THE LOCATION YOU WIRTE IS CORRECT, I AM ABLE TO CHECK ON A GEOLOGIC MAP OF THE AREA.

If you are not 100% sure whether the rock you picked is sedimentary, you may send me a clear picture(s) of your rock along with a reason why you think the rock is sedimentary. Send them via Inbox in Canvas. I can't reply to your request if you don't write WHY you thought the rock was sedimentary. 

If, despite your efforts or because of your personal circumstances (e.g., sick or have disability) you are unable to get the desirable rock, I will give you an alternative assignment. But I need to verify that you have put efforts to find one. And I will know how much efforts you have put on it by the kinds of rocks you will send me (Inboxed or texted images). However, if you are sick or have disability, notify me via Inbox. Make sure you include documentation of your situation. TO GET AN ALTERNATIVE ASSIGNMENT, A STUDENT MUST REQUEST IT VIA INBOX AT LEAST ONE WEEK BEFORE THE DUE DATE FOR THE PROJECT - NO EXCEPTION.

Once you have the sedimentary rock at hand, write a paragraph describing the rock features that include at least the following:

Rock composition (rock components):

Describe the main composition of the rock. Rock components in a sedimentary rock can be one of the following: (1) fossils, (2) mineral crystals, or (3) fragments of rocks or fragments of minerals. 

1. If your rock contains fossils,

• • Describe whether the fossils are whole, broken, or deformed
  • Describe whether the fossils are animal or plant remains

ii. If your rock is dominantly made up of mineral crystals,

• • Describe the color, size, and shape of the crystals (you are not required to name the minerals)

iii. If your rock is made up of rock fragments or fragments of mineral grains:

• • Describe whether the fragments constitute rock fragments only or are mainly made up of broken pieces of mineral grains (note: if the grains are fine or even medium sized, it is difficult to say what kind of fragments you are dealing with)

 

2. Texture and structure of your rock

Texture refers to the size, roundness, and sorting of the rock’s components (i.e. of the fossils, mineral crystals, or fragments of rocks/minerals)

• Grain size (use one of these size terms: gravel, sand, or clay)
• Grain roundness (use one of these grain roundness terms: rounded or angular)
• Grain sorting (use one of these grain sorting terms: well sorted or poorly sorted)

Structure refers to the arrangement of the rock’s components

• Describe any of the following, if present: bedding planes (layering), cross bedding, graded bedding, mud cracks, ripple marks, sole marks, etc.

 

In addition to the above descriptions, if it applies, write a few words regarding

• the rock's weight if it is exceptionally light or heavy?
• any prominent features not listed above.

Don't write about any missing features in the rock:

• You need only to describe those features that are visible in the rock, particularly those rock components and textural/structural features that are essential in classifying and in naming the rock. For example, if you don't find any fossils in the rock, there is no need to say ..... 'the rock doesn't contain fossils.' If a feature is not there, then it is not useful to mention this missing feature.

 

3. Classify and name your rock

Based on your descriptions given in (1) and (2) above and using definitions/descriptions of the various sedimentary types from your textbook, section 5.3.2. (Links to an external site.) and section 5.3.3 (Links to an external site.).,

1. classify your rock as either detrital, chemical, biochemical, or organic sedimentary rock
2. determine the name of your rock. To do this, it will be helpful to use the Classification of Sedimentary Rock (Links to an external site.) Table from your textbook.

I also strongly suggest that you read relevant sections of your textbook to grasp the meaning of many of the specialized sedimentary rock (Links to an external site.) and sedimentary structure (Links to an external site.) terms.

 

4. Explain the paleoenvironment under which the rock was formed

After describing all the features of the rock and have determined what sedimentary rock group (detrital, chemical, biochemical, etc.) and what rock type it is (e.g., sandstone, limestone, shale, etc.) it is, you will explain the environment under which the rock was deposited. Was it deposited by running water, glacier, wind; was the depositional basin a river bank, a delta, shelf area of the ocean, deep marine environment, etc.... You can read about depositional environments  Links to an external site.from your eTextbook.

 

Specifications/Guidelines about the image (picture) of your rock

Your answers must be accompanied by an image or picture of your rock showing all the features you described in (1) and (2) above. For example, if you said the rock contains fossils, your picture must clearly show those fossils; if you said the rock displays crystals, the crystals must be evident in your picture etc. For guidelines on the pictures, read below.

• Your rock must be fresh, not one that is weathered and crumbling (worn out, covered in dirt, or glossed with certain color, etc.). Weathering not only disintegrates the minerals, but it obliterates any textural and structural features in the rock. When weathered, you will not be able to see clearly all the textures and structures of the rock.
• Attach good sized pictures (1/3 to ½ page). Thus, the picture must be taken up-close.
• The rocks you choose must be at least the size of your fist. If your rock is too small or the picture is taken not close enough, your instructor cannot see the rock features clearly and will not be able to verify your descriptions and conclusions. You may end up getting substandard scores.
• If your rock is a hand specimen, when taking the picture place the rock on a flat surface (e.g. desk, ground). To make sure that you don’t plagiarize, write your first name and class number in a white paper and place it by the rock so it is clearly visible in the picture. If you happen to go to the field and have a whole cliff of sedimentary rock, take close-up and wide angle-view pictures of the area with yourself included in at least one of the pictures.
• I suggest you submit at least 3 pictures taken from different angles. This will enable you to show the different textures you describe in your text about the rock and make it easier for your instructor to verify the features.
• When taking the pictures, make sure that there is sufficient natural light, so the features of the rock are clearly visible. Do not use camera flashlight as the reflections will obscure the texture/structure of the rock.
• The picture must be well focused and clear; not something that is blurry. Make sure that you look at the picture and ascertain that you have sharp images of the rock.
• Remember: attaching pictures of your rock is a requirement. Your instructor will not be able to evaluate your observation and interpretation if you don’t provide pictures. If pictures are missing, your assignment cannot be graded and your score for the assignment will be zero.
• Underneath your picture, write the name of the city, town, landmark, or general place name from where you collected the rock sample.
   

How to Submit Your Assignment

To submit your assignment, first create and save your work as a word or pdf file in your computer. Then upload it to Canvas.

Grading will be based on the accuracy of your description of the rock, on the correct use of appropriate scientific terms relevant to the rock, conclusions you make regarding the rock name or rock class, and on the clarity and appropriateness of the pictures.

Feedback on your work will be given to each student directly on the submitted assignment.

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Sample Answer

The rock shows flat (horizontal) layering; The components of the rock are so fine grained that it is difficult to describe their nature. However, being so fine grained, it is safe to conclude that it is made up of mud-sized particles. When touched, the rock feels smooth like clay. Furthermore, there are large, intact, and unbroken animal fossils in the rock. A comparison with fossils shown in our geology textbook suggest that the fossil is an ammonite. The biggest fossil is found near the center of the rock. Presence of fossils in a sedimentary rock indicates that the rock is a biochemical sedimentary rock. Based on the Classification of Sedimentary Rock Chart in our textbook, the rock could be named is fossiliferous mudstone.

Rock location: in San Pedro at the intersection of Gaffey street and 4th street. (Place name and intersection point are fictitious).

Note to the student: Your first name and your class/section number (e.g. Jospeh Biden, Geology 001, Section 22496) written in a piece of paper must be pictured by the side of the image of your rock, or if the picture is taken from far to capture a large rock outcrop, YOU must be in the picture . This is to discourage plagiarism and is a requirement to get full credit. In addition, you need to provide at least three pictures of the same rock taken from different angles.