Assignment: Sedimentary Rock Lab

Module 7 Assignment

Sedimentary Rock Lab

A mountain showing layers of colorful sedimentary rocks

Figure 1. Colorful layers of sedimentary rock in Makhtesh Ramon, Israel

 

Overview

You can start the activity after you have completed the reading assignment.

In Chapter 6 you learned about the different types of sedimentary rocks, and some of the key characteristics. In this lab, you will study photos of several sedimentary rocks and determine their physical properties.

Instructions

A. Before you begin this activity, you may also wish to review the Sedimentary Rock Identification page. Some optional resources you can use are:

B. Select each photo below to view the igneous rock samples larger. You can also view the images in Flickr by clicking the link, and zoom in on each of these samples in the picture to get a better view of their texture:

Select an image to view larger

Smooth flat and layered, black rock in a creek bed of other rocks

Figure 2. Black shale in Whtstone Creek

light colored lumpy rock made of small tube shapes

Figure 3. Calcareous tufa with plant fragments from the Holocene of Ohio, USA (6.7 cm across at its widest). Calcareous tufa is a scarce, calcitic, crystalline-textured, chemical sedimentary rock. It principally forms around cold springs having water relatively rich in dissolved calcium carbonate. Calcareous tufa is often characterized as a lightweight, porous, friable precursor to travertine (another calcitic, chemical sedimentary rock).Here’s a light brown-colored calcareous tufa sample with plant fragments – many of the cylindrical structures visible here are calcite tubes formed around plant stems, axes, or roots. – James St. John

a yellow-orange colored rock with a smoother texture

Figure 4. Sandstone from the Paleozoic of Ohio, USA.Sandstone is the second-most common sedimentary rock on Earth. It is composed of sand-sized grains, which are between 2 millimeter and 1/16 of a millimeter in size each. Most sandstones are dominated by quartz grains, but feldspar sand grains and lithic sand grains (= sand-sized rock fragments) are often present as well.– James St. John

a yellow and borwn rock made up of many pieces a number 1 sticker is on the top

Figure 5. A sample of a conglomerate rock.

a light colored rock with a viable fossil on its surface

Figure 6. Grand Canyon_Fossil Brachiopod in Kaibab Limestone

   

C. Determine the following characteristics to the best of your ability from the photos of the samples above:

  1. Color
  2. Texture (clastic or crystalline/chemical?)
  3. Approximate Grain Size (for clastic rocks only: fine, medium, or coarse grained?)
  4. Sorting (for clastic rocks only: well-sorted, poorly-sorted, or somewhere in between?)
  5. Depositional Environment (in what general environment was this rock originally formed?)
  6. Compare your personal observations with the information in the course Rock and Mineral Guide (above). How is each sample different (or similar) from the Guide?
  7. For one of the rock samples of your choice, write a half-page summary describing the physical characteristics you can determine from the photo or from any personal sample you have collected. If using a personal sample, please include a photograph. For all the other samples above, include a table summarizing the characteristics you observed (1 – 6). You will be graded on this activity as described in the rubric below.

Grading Rubric

10 points: Report accurately summarized the sedimentary rock characteristics, spelling and grammar are correct and complete sentences are used, including a photograph. Characteristics of the other samples are included in a table and are accurate.

8 points: Report mostly captured the sedimentary rock characteristics, spelling and grammar are mostly correct and complete sentences are used, including a photograph. Characteristics of the other samples are included, but one or two details were missing.

5 points: Report missed two or more characteristics, included spelling and grammar errors, and/or did not include a photograph. Characteristics of the other samples are included, but over half of the samples and/or characteristics are missing.

2 points: Report was inaccurate, included significant spelling and grammar errors, and/or did not include a photograph. Characteristics of the other samples are not included.

0 points: Did not complete the assignment.