Lab field assignment
- 1. Lake Tahoe Annie Brejc Emerald Bay at sunset
- 2. History Of Lake Tahoe The Basin was formed from the rising and falling of the landscape due to faulting. 24 million years ago, the Sierra Nevada block was formed by uplifting The Carson Range is on the eastern side and the western side consists of the Sierra Nevada range. Lava flow from Mt. Pluto created what we now call the Truckee River (Geology of Lake Tahoe Basin). Melting snow and other water flows created lakes above the Lake Tahoe.
- 3. History of Lake Tahoe An ice age developed after the volcanic period, creating huge glaciers that moved down the canyons that resulted in U-Shaped valleys (Geology of Lake Tahoe Basin). These glaciers left behind the rigid mountains and the beautiful bays that we have today. The Lake that we have today is the tenth deepest lake in the world, with an average depth of 1,000 ft. (the deepest measured is 1,645ft).
- 4. Lake Tahoe Mount Tallac 9,738 ft The picture on the left and right are captured off Emerald Bay Road at sunset
- 5. Black Bear The evolution of bears started about 30 million years ago. The developed from a family called Miacids There are three subfamilies within the bear family: Giant Panda, the spectacled bear, and the real bears. The real bear species has strong claws and a robust body (black bears). A bear’s diet is mainly vegetarian, though they are classified as omnivores. Bears have been evolving for the last 5 million years and have acquired a wide geological distribution (Bratpack).
- 6. Black Bears in Lake Tahoe In California there is an estimated 25,000 to 35,000 black bears. The male bear is much larger than the female, which have an average weight of 300 pounds. They are very strong swimmers and tree climbers. Also they can sprint up to 35 mph. Bears are hibernators, meaning that when winter is approaching they begin to forage for food that stores enough fat to allow them to survive 40 to 50 feet off the ground all winter (Kumar 2017).
- 7. Black Bear Black Bears are hard to capture but these are pictures of different colored black bears found in Lake Tahoe
- 8. Jeffery Pine The Jeffery Pine is spread out from southwestern Oregon, to western Nevada, and to Baja California. Jeffery Pines are slow growing and long lived conifers. They are very tall reaching up to 200 feet and have a diameter of up to 8.2 feet. The top of the tree is either rounded or long and is symmetrical. They have a very thick trunk covered in large plates of bark (Pinus Jefferyi). The needles of Jeffery Pins usually are in bundles of 3 and stretch from 3-11 inches. The largest Jeffery Pine cones are found in the Reno-Tahoe area. They have honeycomb-like pinecones that vary in size.
- 9. Jeffery Pine The Jeffery Pine sexually reproduces through seeds. The seed may drop as far as 100 feet from the parent tree and then due to weather is blown farther away (Delevoryas 2016). Jeffery Pines can survive in different types of soil. In the Sierra Nevada range Jeffery pines grow in volcanic soils. Jeffery Pines originated about 400 million years ago with the first appearance of a seed. Then came the gymnosperm, which were dominant in the Mesozoic Era. Gymnosperms are flowerless place and reproduced by an exposed seed (Delevoryas 2016).
- 10. Jeffery Pine Jeffery Pines are found all around Lake Tahoe These are in my backyard
- 11. Chipmunk Chipmunks are omnivores. Their diet consists of nuts, seeds, insects, small frogs, worms, and bird eggs. Chipmunks will begin to collect food in the fall and store it in their burrows for winter. They are small, striped mammals. They are quick on the ground and are able to climb trees to retrieve seeds. They are about 4-7 inches with a tail that is 3-5 inches and they weigh from 1-5 ounces (Chipmunks 2018). Chipmunks live for about 3 years They are an important factor in seedling establishment.
- 12. Chipmunks Squirrels, and chipmunks (direct descendants) were found in fossil remains dated back to 30 million years ago. Originally from Eurasia, this species’ migrated through the land connection between Alaska and Siberia that existed nearly 7 million years ago. (Musser 2019).
- 13. Granite This rock is something I have seen my whole life, as it is prevalent in my backyard. Granite is an igneous rock, which means at one point it originated from volcanic deposits. As previously described this is one of the remarkable features of our local flora and fauna, coming from Mt. Pluto. My identification process was based on its physical characteristics (colors) and its visible grain.
- 14. Granite Found in Christmas Valley in Myers
- 15. Scoria This rock is igneous. It has little texture, and contains mostly black/gray minerals which are visibly fine. This rock is soft, as it does not scratch fingernails at all when testing it against them. There are some visible bubbles, smaller than a pea, but not evenly distributed. FoundbehindLake TahoeCommunity College
- 16. Sandstone This rock has a lot of texture, so it cannot be igneous. It looks like many different colors and layers. It appears to be sedimentary as the edges are not smooth and seem to have been affected by the environment. Layers appear to be sandy or claylike, which I inferred from its brownish-gray coloring. Grain size is not as fine as the previous rock, so I believe it to be coarse. It scratches fingernails, so definitely not soft. Found Behind Lake Tahoe Community College
- 17. Law of Superposition The law of superposition states that sediments/materials accumulate on top of each other, and thus the oldest sediments would be at the bottom of the stratified layer (Law of Superposition 2019). This is visible in Tahoe when at the bottom of the beach by Cave Rock on US-50.
- 18. Disconformity This fault occurs when the same layering is present both above and beyond the disconformity. This is visible in the same cliffs described as the law of superposition. This occurs in sedimentary layers, which are different in age but which have similar or equal layering
- 19. References Bratpack, & Internetdiensten, B. (n.d.). The evolution of bear species. Retrieved from https://www.bearsinmind.org/Page/The-evolution-of-bear-species Chipmunks. (2018, September 24). Retrieved from https://www.nationalgeographic.com/animals/mammals/group/chipmunks/ Delevoryas, T. (2016, October 18). Gymnosperm. Retrieved from https://www.britannica.com/plant/gymnosperm Geology of the Lake Tahoe Basin. (n.d.). Retrieved from https://www.fs.usda.gov/detail/ltbmu/learning/?cid=stelprdb5109570 Kumar, V., Lammers, F., Bidon, T., Pfenninger, M., Kolter, L., Nilsson, M. A., & Janke, A. (2017, April 19). The evolutionary history of bears is characterized by gene flow across species. Retrieved from https://www.nature.com/articles/srep46487 Law of superposition. (2019, April 09). Retrieved from https://en.wikipedia.org/wiki/Law_of_superposition Musser, G. (2019, January 23). Chipmunk. Retrieved from https://www.britannica.com/animal/chipmunk Pinus Jeffreyi. (n.d.). Retrieved from https://www.fs.fed.us/database/feis/plants/tree/pinjef/all.html