Glen Alpine to Grass Lake In Desolation Wilderness GEL 103 Field Assignment by: David Brent 7/14/12
Table of Contents • Location • O ver view • Geological Background • Soda Spring • Roc k S amples • California Corn Lily • Sierra Garter Snake • Resources
Location This 5.45 mile hike into Desolation Wilderness begins at the Glen Alpine Trailhead near Fallen Leaf Lake. The trail begins by following the old road to the Glen Alpine Springs Resort. The trail reaches Grass Lake at its southeastern tipand follows the southern shorelineto the northwest. After a little ways there will be nice views looking over the lake to the northwest towards the mountains, (1). - Z & B Johnson’s Adventures
Overview Before reaching the trailhead, be sure to stop and look at the Glen Alpine Falls. These are a beautiful set of waterfalls dropping about sixty feetdown large dark boulders into a narrowcanyon. The creek above the falls up to Lily Lake is also beautiful, with numerous deep rock gorges. Three more lesser waterfalls await along the trail before reaching a gorgeous viewpoint at Grass Lake for the bestwaterfall of the bunch, Susie Lake Falls (shown on the following slide), (3). Glen Alpine Falls
The panorama surrounding thisgorgeous location was formed over millions of years through geologicactivity and environmental changes. Desolation Wilderness consists of over 63,000 acres of beautiful alpine forest and glacial valleys containing lakes, rivers, hiking trails, and tall peaks for climbing. Desolation Wilderness has it all! Grass lake is surrounded by the characteristic Desolation granite and has a pretty cascade that tumbles down cliffs on the west side.
Geological Background• The geologic history of Lake Tahoe began nearly 400 million years ago when a shallow sea covered the area that is now the Sierra Nevada Mountains. For hundreds of millions of years, mud, sand, and shells were slowly deposited on the floor of this ancient sea. The weight of the thousands of feet of sediment combined with chemical processes turned the mud, sand, and shells into mudstone, sandstone, and limestone rock.• At the same time, about 210 million years ago, the Pacific Plate (the sea floor underneath the Pacific Ocean) crashed into the edge of the North American Plate (the land and continental shelf of North America) and was pushed down under the North American Plate. This process, known as subduction, is how most volcanoes and all granitic rock is formed, (7).
Extensive glaciation shaped the surface of Desolation Wilderness. Ice sheets over 1,000 feet deep covered the western slopes and all but the highest peaks of the Tahoe Basin during the last ice age (over 200,000 years ago). The sheer mass and grinding action of the ice packs scoured out the basins where nearly 130 lakes formed throughout the Desolation area, (5).Most of Desolation Wilderness clearly shows its icy heritage .
In 1863 Nathan Gilmore discovered Glen Alpine Springs. It was originally known as Soda Spring because of the natural carbonation of the water. In 1884 Gilmoredeveloped a health spa resort here and began bottling the water and selling it, (2).
Rock Sample: Granite• Granite is an intrusive igneous rock, meaning that it is composed of formerly molten material that cooled below the surface. When molten rock hardens before reaching the surface it cools relatively slowly, which promotes the formation of large crystals of different minerals, giving the rock a distinctive salt and pepper appearance. • The Sierra granitic rocks were formed as a result of the subduction of a denser oceanic crustal plate beneath the western margin of the North American plate as the two plates collided. Subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate and sinks into the mantle as the plates converge. The location of the subduction zone was on the western edge of the Sierra Nevada region in the foothills separating it from the Central Valley, (8).
Rock Sample: Sandstone• The oldest rocks in the Sierra Nevada are quite a bit older than the granitic rocks. A number of peaks in the eastern Sierra are capped by rocks that are distinctly different than granite. Some of these rocks appear to be metamorphosed versions of the sedimentary rocks that are common in the Basin and Mojave regions. As the plutons of molten rock shouldered their way to the surface, they came in contact with sedimentary rock of the shallow Sierra sea (including sandstone, mudstone, and limestone). • Sedimentary rocks (like sandstone) are formed by the lithification (cementing, compacting, and hardening) of existing rock or even the bones, shells, and pieces of formerly living things in the area. Rocks are weathered and eroded into tiny particles which are then transported and deposited along with other pieces of rock called sediments, (8).
California Corn Lily (Veratrum Californicum)• A poisonous plant native to mountain meadows between 3,500 to 11,000 feet in southwestern North America, the Sierra Nevada and Rocky Mountains, and as far north as Washington State. • It grows 1 to 2 meters tall, with an erect, un-branched, heavily leafy stem resembling a corn stalk. It prefers quite moist soil, and can cover large areas in dense stands near streams or in wet meadows. • Many inch-wide flowers cluster along the often-branched top of the stout stem; they have six white petals, a green center, six stamens, and a three-branched pistil. The buds are tight green spheres (as seen to the left). • The heavily veined, bright green leaves can be more than a foot long (as seen on the following slide). • Also referred to as the “Skunk Cabbage,” (9).
Sierra Garter Snake• Garter snakes have toxins in their saliva which cab be deadly to their prey and their bite may produce an unpleasant reaction in humans, but they are not considered dangerous to humans.• They eat mainly fish and amphibians and their larvae: including frogs, tadpoles, and aquatic salamander larvae.• Northern populations have mottled black coloring below. This mottling is not present in southern populations. Populations in streams draining into the Sacramento River all lack lateral stripes.• They are regularly found in seasonal creeks, large mountain rivers, meadow ponds, and small lakes, (10).
The Sierra Garter Snake ranges from the Pitt and Sacramento rivers south along the Sierra Nevada Mountains to the western end of the Tehachapi Mountains.
Sierra Garter Snake• There is fossil evidence, thanks to a find in the Saharan Desert in Africa, that the earliest snakes appeared about 130 million years ago during the early Cretaceous period. This fossil was given the name Lapparentophis defrenni. Though incomplete, the fossils vertebrae were consistent with that found in todays snakes.• Most paleontologists agree that reptiles evolved from Labrynthodonts. The biggest evolutionary gain was the advent of the shelled egg, or amniote. This meant that the reptiles could lay their eggs on land and not have to return to the water to breed like their amphibian ancestors, (12).
For a first time visitor, the network of trails can be a bit confusing. Grass Lake can be easily found if you bare left at the junction marked "Grass Lake - Gilmore Lake". Remember to bring good trail shoes, a camera, wildflower guide, fishing pole, and a swim suit for an exceptional outdoor experience.
Resources1. "Glen Alpine to Grass Lake - Z & B Johnsons Adventures." <https://sites.google.com/site/zbjohnsonadventures/hikes/california-nevada/glen-alpine-grass-lake>.2. "Glen Alpine Springs â€¢ Hiking â€¢ California â€¢ HikeArizona.COM." <http://hikearizona.com/decoder.php?ZTN=15364>.3. "Glen Alpine Creek and Falls." Glen Alpine Falls. <http://www.aboutlaketahoe.com/hiking/glen_alpine_falls.htm>.4. "Desolation Wilderness in California." AllTrips: Lake Tahoe. <http://www.alllaketahoe.com/nature/desolation_wilderness.php>.5. "Desolation Wilderness." Desolation Wilderness - Sierra Nevada Geotourism MapGuide. <http://www.sierranevadageotourism.org/content/desolation-wilderness/sie45201DE7F7C3C332A>.6. "Grass Lake." Grass Lake - Sierra Nevada Geotourism MapGuide. <http://www.sierranevadageotourism.org/content/grass-lake/sieD0B2608FB727DA281>.7. "Lake Tahoe Facts, Natural History, & Human History." Lake Tahoe Facts. <http://www.tahoeadventuresports.com/misc/tahoefacts.htm>.8. "Sierra Nevada Physical Geography." Sierra Nevada. <http://www.geog.ucsb.edu/~joel/g148_f09/readings/sierra_nevada/sierra_nevada.html>.9. "Veratrum Californicum." Wikipedia. Wikimedia Foundation. <http://en.wikipedia.org/wiki/Veratrum_californicum>.10. "Thamnophis Couchii - Sierra Gartersnake." Thamnophis Couchii. <http://www.californiaherps.com/snakes/pages/t.couchii.html>.11. “Fossil Snake Facts." ehow.com. <http://www.ehow.com/facts_5819776_fossil-snake.html>.