Sedimentary Layering EarthCache
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This is a great area to view the layers of sedimentation of an ancient Lake called Lake Claron that once covered the area around 60 million years ago. When the road cut into the hill side, it opened up a view of the Sediment Layers of a Ancient Lake. The Sediment layers are remnants of floods that once flowed into the Lake and then Settled on the bottom of the of the Lake. you can also see a layer of "Blue Clay", or petrified forest member, which were once the decaying remains of plants and trees that settled to the bottom of the lake. One of the really great features you can see here is that in this particular area you can see how the layers were deposited and then at one point the lake level must have dropped and then there was some erosion that occurred forming a U shape cutting through the previously deposited layers. Then the water levels raised covering the area again and allowing more sediments to be deposited, thus filling in the area that was eroded.
Example of how sedimentation occurs.
Formation of these rocks is one of the important parts of the rock cycle. For millions of years, the process of deposition and formation of these rocks has been operational in changing the geological structure of earth and enriching it.
Let us now see how sedimentary rocks are formed.
Weathering
The formation process begins with weathering of existent rock exposed to the elements of nature. Wind and water are the chisels and hammers that carve and sculpt the face of the Earth through the process of weathering. The igneous and metamorphic rocks are subjected to constant weathering by wind and water. These two elements of nature wear out rocks over a period of millions of years creating sediments and soil from weathered rocks. Other than this, sedimentation material is generated from the remnants of dying organisms.
Transport of Sediments and Deposition
These sediments generated through weathering are transported by the wind, rivers, glaciers and seas (in suspended form) to other places in the course of flow. They are finally deposited, layer over layer by these elements in some other place. Gravity, topographical structure and fluid forces decide the resting place of these sediments. Many layers of mineral, organics and chemical deposits accumulate together for years. Layers of different deposits called bedding features are created from them. Crystal formation may also occur in these conditions.
Lithification (Compaction and Cementation)
Over a period of time, as more and more layers are deposited, the process of lithification begins. Two sub-processes that are a part of lithification are compaction and cemenation. Compaction is the compression of the sediments under overlying weight of sediments. Cementation is the process of filling in the gaps in sediments with minerals that gel them together. Crystal formation may occur here too. With these two processes at work, what was a loose layer of deposits, hardens and solidifies to become rock. This is the conclusive stage.
To get credit for this cache email me with the answers to these questions.
1. Are all the layers of sediment the same thickness?
2. what does this tell you about the floods entering this lake?
3. Looking at the erosion that occurred in the layers, how many layers of new sediment did it take to fill the "U"?
4. Number of and Names of People in your Group.
5. Photo of you at the site. (this is optional, and not required for logging)
Additional Hints
(Decrypt)
Ba gur ubg fhzzre qnlf, whfg fgnl va gur pne jvgu gur NP ba!