Field assignment - Bassi Falls
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Field Assignment Bassi Falls
Field Assignment Bassi Falls
Tracie ButlerGEL 103 J1 ML SU11Bassi Falls
ContentsOverview of field trip and details of identifying subjectsSite location informationArea geologic historyRock TypesWildlife typesFlora typesRock TypesDeciduous Tree typesReferences
Details about contents and researchPersonal history of Bassi FallsAll example photos contained in this report were taken by me. Most were taken during my visit to Bassi Falls July 2011 or during a previous trip. There are a few taken a couple of years ago (noted). None other unless otherwise noted in the reference sectionMap Images were produced using Google EarthRock Identification was done using USGS web searchFlora identification was done using the United States Department of AgricultureTree identification was done using the Malheur Experiment Station, Oregon State University.Wildlife identification was done using All About Birds website
Personal History of Bassi FallsOur family has been coming to Bassi Falls for 3 years. I love going to Bassi Falls because I enjoy being outdoors, hiking, soaking up the sun and spending time with my family. We make the hike up to the falls at least three times a year during the summer and fall months. In all the times weve visited this place, Ive never really seen what was all around me. I mean, I saw the awesome forces that water has on something as hard as granite, how colorful and delicate the flowers are that surround the flowing stream, tasted how sweet fresh water can be and marveled at the beauty we centered ourselves within. During this field trip, I discovered some truly amazing natural occurances that are documented in the following. I hope you enjoy seeing and learning about this place as much as I do Site LocationLocated near the Crystal Basin, Union Valley Resevoir, Bassi Falls, CA North El Dorado CountyOff Hwy 50 to Ice House RoadElevation: ~5,600ftPrecipitation Range: 20 to 80 inches, occurs mostly as snow above 6,000ftCoordinates: Latitude: 38.890458Logitude: -120.325502Google maps: search, Bassi FallsLocated in El Dorado National Forrest
One look at this picture and you can see how powerful the forces of water can be. Over the course of millions of years, the fall waters have made its way through tiny cracks in these boulders. During the winter freeze, those cracks expand and eventually break off as seen in this picture.Geologic History of Bassi Falls AreaBassi Falls is found in the El Dorado National forest, which is located in the Sierra Nevada Mountains. The Sierra Nevada Mountains is a mountain range in California and Nevada, between the California Central Valley and the Basin and Range Province. The Sierra Nevada mountain range runs 350 miles north-to-south, and is approximately 70 miles across east-to-west. Notable Sierra Nevada features include Lake Tahoe, the largest alpine lake in North America; Mount Whitney at 14,494 feet, the highest point in the contiguous United States; and Yosemite Valley, sculpted by glaciers out of 100-million-year-old granite. About 150 million years ago, during the Jurassic period, granite formed deep underground. The range started to uplift four million years ago, and erosion by glaciers exposed the granite and formed the light-colored mountains and cliffs that make up the range.Knowles, (n.d.)Water flow: Source & Destination
Bassi Falls is fed by snow melt from Forni Lake, elev. ~7900ft, (and another smaller unlabeled lake below McConnell Peak) via Bassi Fork and drains into Union Valley Reservoir. In this picture, the arrow points to an area against the stream bed that shows evidence of erosion as indicated by round, smooth igneous rocks as well as the overburden on top of the rocks from uphill erosion OverburdenSmooth Rounded RocksDuring the summer months Bassi Falls is a continuous cascade over granite bedrock and boulders National Geographic Topo Maps, search Bassi Falls, El Dorado County, CA (2001)Mechanical Weathering
Rocks have pours and fractures (voids) in the surface, and when moisture is introduced (i.e., flowing waters from a fall such as Bassi Falls) it tends to collect in these voids. In higher elevations, such as where Bassi Falls is located, temperatures drop during the night and cause the water in the voids to freeze. When the water freezes, it expands and presses against the crack causing it to grow wider. Eventually, as this process reoccurs repeatedly over time it causes the rock to break off into smaller chunks. This type of mechanical weathering is called ice wedging.In the picture to the right, you will see an example of this type of weathering and its affects on this piece of granite.Abrasion
When a rock is broken down by physical forces such as water or wind, it changes the rock physically, but the chemical structure remains the same. In the picture to the right, a granite boulder has been worn smooth by friction from sand and other rocks tumbling and bumping against them as they are carried by the force of the water. This is called abrasion. Rocks
Type: Granite with a Quartzite intrusionIn this picture, the intrusion runs through a bed of granite. The orange coloring indicate staining. Staining is caused by felsic minerals (iron rich) oxidizing in the granite. Pellant, C., & Pellant, H. (2002)Rocks Granite Example
Type: Granite It is evident that one side of the rock has a different texture than the other. During the time this rock was being formed, there is evidence that one side cooled much faster indicated by the fine grain texture. The course side cooled at a much slower rate as indicated by the larger crystals. With that said, one side is a fine-grained granite leaving the opposite side a course grained granite.
WildlifeType: Steller Blue Jay, Cyanocitta stelleriTwo years ago, I was fortunate enough to have a female Steller Jay make her nest in the eaves of our porch. The pictures you see on the left are of this Steller Jays, which we named Stella, nest.Native to North America, the Steller jay was first discovered on an Alaskan Island by naturalist Georg Steller in 1741. The bird was officially named by a scientist in 1788 Nesting facts - incubation of 16 days for a clutch of 2-6 eggs. Their eggs are usually Bluish-green spotted dark brown, purplish, or olive.Their diet consists of seeds, insects, berries, nuts, small animals, eggs and nestlingsStellers are birds of coniferous and coniferous-deciduous forests. They are typically found in elevations between 3,000 and 10,000 feet. Todays birds are a group of theropoddinosaurs that evolved during the Mesozoic era.
Dunne, Dobkin, Ehlrich, Greene, & Davison (n.d.)History of birdsScientific ClassificationKingdom:AnimaliaPhylum:ChordataClass:AvesOrder:PasseriformesFamily:CorvidaeSpecies:Cyanocitta stelleriCommon:Steller's jayI was unable to find the exact origin and evolution of the Cyanocitta sterrleri in particular; however, there is significant evidence that birds evolved from theropod dinosaurs, specifically, that birds are members of Maniraptora, a group of theropods which includes dromaeosaurs and oviraptorids, among others. Birds are categorized as a biological class, Aves. The earliest known species of class Aves is Archaeopteryx lithographica, from the Late Jurassic period, though Archaeopteryx is not commonly considered to have been a true bird. Modern phylogenies place birds in the dinosaur clade Theropoda. According to the current consensus, Aves and a sister group, the order Crocodilia, together are the sole living members of an unranked "reptile" clade, the Archosauria. Phylogenetically, Aves is usually defined as all descendants of the most recent common ancestor of a specific modern bird species and either Archaeopteryx, or some prehistoric species closer to Neornithes. If the latter classification is used then the larger group is termed Avialae.
Padian K & Chiappe LM 1997FloraType: Mountain Spiraea
Mountain Spiraea (Spiraeasplendens). Also known as Rose Meadowsweet. Photo taken at Bassi Falls alongside the stream.SpiraeasplendensKingdomPlantae PlantsSubkingdomTracheobionta Vascular plantsSuperdivisionSpermatophyta Seed plantsDivisionMagnoliophyta Flowering plantsClassMagnoliopsida DicotyledonsSubclassRosidaeOrderRosalesFamilyRosaceae Rose familyGenusSpiraeaL. spireaSpeciesSpiraeasplendensBaumann ex K. Koch rose meadowsweetVarietySpiraeasplendensBaumann ex K. Koch var.splendens rose meadowsweetBaumann ex K. Koch var.splendensUS Dept of Agriculture,(n.d.)The mountain Spiraea is an angiosperm, or a flowering plant. Flowering plants, also known as Angiospermae, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies (derived characteristics). These characteristics include flowers, endosperm within the seeds, and the production of fruits that contain the seeds.The ancestors of flowering plants diverged from gymnosperms around 245202 million years ago, and the first flowering plants known to exist are from 140 million years ago. They diversified enormously during the Lower Cretaceous and became widespread around 100 million years ago, but replaced conifers as the dominant trees only around 60-100 million years ago.
ITIS Report (2011)16Sierra Nevada TreesType: Lodgepole Pine
Pinus contortaCommon name: Lodgepole PineFamily: PinePlant Type: TreeShort Description: Medium length needles, thin bark, small cones. Leaves: needles in 2'sNative: YesShock, Oregon State University, (n.d)McLamb & Hall (n.d.)The earliest known modern tree is the Archaeopteris, a tree that looked similar to a Christmas tree with buds, reinforced branch joints and wood similar to today's timber. Its branches and leaves resembled a fern.
When the archaeopteris tree first appeared 370 mill