Introductory Physical Geology 1

Project 1 Examine Rock Samples

Collect at least 10 different, fist-sized rock samples from local quarries, gravel pits, rock piles, or river beds. (Note: Be sure that you get permission to enter and collect samples from quarries or gravel pits.) Crack each sample open with a hammer to provide a fresh, unweathered surface for examination. If possible, do this at the collection site, since some samples may be weathered throughout. You should find samples that have a fresh, unweathered surface when cracked open.

For each sample,

1. provide a sketch of the sample, showing any distinctive features (e.g., pebbles, vesicles, veins, laminations, etc.), with a scale to show size. For coarser-grained rocks, provide a blow-up sketch to show the textural features of the grains.

2. examine the fresh, unweathered surface, and describe the grain size, texture, and mineral composition (if phaneritic). Follow the identification procedures you learned in Laboratory Exercises 1-4, and provide a rock name for the sample.

3. describe the weathered surface in terms of colour, texture, and distinctive characteristics. Describe the differences between the weathered and unweathered surfaces. Are some structures and textures more visible on the weathered surface? Is it easier to identify some minerals on the weathered surface?

4. speculate about the origin of the sample, that is, the type and possible locations of the outcrop from which it came. Does the rock type occur as outcrop in the province? If not, how did that rock type get to be where you found it? Obtain a geological map of your province (the Athabasca University Library has copies of Alberta geological maps; alternatively, you may contact the department of resources for your province). You should include a sketch of the province in your report, showing your collection locality or localities. Where possible, also indicate source areas on your sketch map.

Note: If you choose this project, the introduction of your report should state the objectives of the project, describe the source of the data (e.g., pebbles, cobbles from a rock pile), indicate the location from which you obtained your samples (perhaps with a reference to the sketch map of Alberta) and give any other necessary background information.

Project 1 Examine Rock Samples