Tahoe -- Emerald Bay Earthcache EarthCache
Tahoe -- Emerald Bay Earthcache
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As an earthcache, there is no “box” or “container” to discover. Rather, with this cache, you discover something about the geology of the area. For more info, consult www.earthcache.org
For paperless cachers, the logging requirements are at the beginning of the description.
The Emerald Bay Interpretive Pullout offers visitors a wonderful opportunity to learn about the history and geology of Emerald Bay. Emerald Bay is one of the most photogenic spots for great photos of Lake Tahoe. It is a small bay, only 3 miles long, and one mile wide.
Logging Requirements:
Send the answers to #1-#4 to me through my geocaching profile.
1. List the name “GC2N921 Tahoe -- Emerald Bay Earthcache” in the first line of your email. Also, list the number of people in your group.
2. What is the elevation at GZ?
3. Compare/Contrast the SHAPE lake edges slope of Emerald Bay and Fallen Leaf Lake with LAKE TAHOE (2 differences).
4. From the Description, What is the rock and gravel left behind by the sliding glaciers called? There is some visible from GZ (or at least from that parking lot area) What direction?
5. DO ONE: 1) Send to my profile-- Finish the sentence from posted signage at GZ: At 1,600 feet deep, Lake Tahoe is the third deepest lake in North America. The bottom of the lake is actually 95 feet lower than __________. 2) Post a picture of yourself and/or your GPS with your log that shows Emerald Bay in the background. Vacation photos from five years ago do NOT count! DO NOT show any of the pertinent information panels in your picture or your log may be deleted.
I will only respond if you have incomplete logging requirements. Go ahead and log your cache
Unlike Lake Tahoe, with a varied geologic history, Emerald Bay was formed primarily by glacial action.
Glaciation:
Long after Lake Tahoe formed, huge glaciers in the Northern Sierra Nevada created a number of lakes surrounding Lake Tahoe. Sliding down V-shaped canyons on Lake Tahoe’s western side, the glaciers scoured away rock and created broad U-shaped valleys. Filled with snowmelt water, the resulting elongated depressions are now known as Fallen Leaf Lake, Emerald Bay, and Cascade Lake. The rock and gravel left behind at the side and end of a melting glacier are called moraines. You may be able to view some moraines (in season) as you travel up the highway towards Emerald Bay. In fact, according to "Quaternary Geology of the United States (2003 edition)" the road you drive between Fallen Leaf Lake and Emerald Bay is likely a moraine! Also from this book, There are two major glaciations in this area -- the Tahoe and the Tiogan. When these two glacier systems were flowing, they were doing so from up to 9900 feet above sea level -- now that is a lot of ice! "At Fallen Leaf Lake, the Tioga glacier apparently terminated on a flat outwash plain that preserves numberous small end morainses." The moraines are well preserved, and easy to spot throughout the region. In fact, there is a "moraine trail" to the northwest (see Forest Service maps) that follows (and makes contrasts easy) between Tioga and Tahoe moraines (but that's a different type of geology lesson).
Some of the mountain peaks in the Tahoe basin escaped glacial erosion during the last ice age. Taller than the advancing ice, peaks like Mt. Tallac, Jacks, and Dicks retain their dark metamorphic rock, which was eroded away on lower peaks. Because of greater exposure to winter water and freezing temperatures, the taller peaks are more jagged than surrounding granite peaks.
Faulting:
Often thought to be a collapsed crater, Lake Tahoe was in fact formed by the movement of the earth’s crust. About 2.5 million years ago, tremendous uplifting formed the Sierra Nevada block of the crust. The valley that later became Tahoe Basin sank between two parallel faults as the Sierra Nevada and the Carson Range rose on either side.
At 1,600 feet deep, Lake Tahoe is the third deepest lake in North America. The bottom of the lake is actually 95 feet lower than __________ (see logging requirement).
Congrads to MathProfessor for FTF (First to Finish logging requirements) on 2/4/2011
Resources:
Information panels at GZ
Additional Hints
(No hints available.)