Don't go getting all Sedimental on me EarthCache
Don't go getting all Sedimental on me
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Difficulty:
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Terrain:
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Size: 
(other)
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The posted coordinates are only a suggested reference point, but the questions for this Earthcache can be answered from anywhere along the Eastern side of the trail.
Sediment, also known as siltstone, is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice, and/or by the force of gravity acting on the particles. For example, silt falls out of suspension via sedimentation and forms soil (some of which may eventually become sedimentary rock). Sediments are most often transported by water (fluvial processes), wind (aeolian processes) and glaciers. Beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans Seas, oceans and lakes accumulate sediment over time. The sediment could consist of terrigenous material, which originates on land, but may be deposited in either terrestrial, marine, or lacustrine (lake) environments; or of sediments (often biological) originating in the body of water. Terrigenous material is often supplied by nearby rivers and streams or reworked marine sediment (e.g. sand).
In the mid-ocean, living organisms are primarily responsible for the sediment accumulation, their shells sinking to the ocean floor upon death. Deposited sediments are the source of sedimentary rocks, which can contain fossils of the inhabitants of the body of water that were, upon death, covered by accumulating sediment. Lake bed sediments that have not solidified into rock can be used to determine past climatic conditions.
In most cases, sedimentary deposits can be clearly seen from satilite. Here, you can clearly see how far out sediment from Colma creek has flowed out into the bay. Though at higher tides it's less visible under the water when looking from a ground level.
Depending on the tide level and time of day, more or less of the sediment siltstone will be visible.
In order to log this Earthcache:
Send me an email with the following information:
1. The name and CG# of this Earthcache
2. How far out (estimate in feet) the siltstone was visible between the shore and the waterline during the time of your visit.
3. Sediment can be classified based on its grain size and/or its composition. Using the table below, under which Wentworth Size class would you consider the furthest visible layer of siltstone from where you are currently standing?
Use the following table for reference:
Congratulations bthomas on FTF!
Additional Hints
(Decrypt)
Lbh'er ybbxvat sbe ubj zhpu "Zhq" vf ivfvoyr orgjrra gur jngre naq gur genvy.