1. Geology 3 Field Assignment Sheila Burke Geol-3-C01 May 22, 2011
2. Mudcracks Mudcracks are a sedimentary structure that form around the time of deposition, but before lithification. They are useful in reconstructing ancient environments (Levin, 2010). This picture of mudcracks was taken in a dried out area of a canal. They likely developed from the shrinkage of the mud after drying out once the water evaporated. This has created a breeding ground for plant life and new dwellings for insects and other life forms such as snakes, mice, squirrels, and several others.
3. Graded Bedding Graded bedding is another sedimentary structure and it occurs when flowing water sorts particles by size. This creates beds where the coarsest grains are at the base while gradually getting finer towards the top (Levin, 2010). This graded bedding occurred in a canal likely from a rapid settlement of coarser and heavier grains in a sedimentary mix. In the picture to the right, you can also see a white line that is likely a water mark showing how the levels of water have changed over time.
4. Evolution of Trees These are two separate trees that show how, over time, trees grow and how you can tell their age. The tree on the left has grown rather large over what is likely a great period of time. The tree on the right, however, is a stump that was next to another large tree. This tree appears to have been chopped or broken down. Due to this, we are able to see the rings within the stump that clue us in to how old it is. To my untrained eye, this tree looks to be about four years old. Unfortunately, this is not the most reliable way of determining a tree’s age because trees often go a year without producing a ring or they produce more than one ring in a year’s time (Earle, 2011).
5. Land Plants These are pictures of land plants taken in the same canal as most of the other pictures, but also from right outside my front door in my flower bed. The plants to the left have grown in parts of the canal that have become barren. The plants to the right, however, are an example of angiosperms. Angiosperms are flowering plants that evolved from pollen grains (Levin, 2010). Both types of land plants are a breeding ground for insects, birds, and some mammals. The flowers are most important to insects such as bees for pollinating purposes.
6. References Levin, H. (2010). The Earth Through Time. 9th ed. Hoboken, N.J.: John Wiley & Sons, Inc. Earle, C.J. (2011). The Gymnosperm Database. http://www.conifers.org/topics/oldest.htm
