Sand Dunes
A sand dune is "a mound or hill of sand built by wind or the flow of water", beyond the maximum extent of waves. They can occur in different shapes and sizes, dependent on the interaction with the flow of air or water.
They are formed when wind-blown and sea-deposited sand accumulates against an obstruction such as rocks or vegetation. In the case of Par, it is the artificial roads and infrastructure that has been built along the seafront, and is the trigger for the dunes to grow here. However, dunes always grow parallel of the seafront.
There is a constant input of sand from Longshore Drift, a process by which sediment (including sand) is transported in a zig-zag direction along a beach, determined by the wind and wave directions. Swash (water coming in) and prevailing wind pushes sand up the beach, and backwash (water coming out) pushes material down the beach. Longshore Drift transports the sand enough for it to deposit and accumulate onto a dune.
As more sand deposits and accumulates, the dune grows, and forms the uneven mounds you see here. Vegetation can form on dunes (and has here), as sand can absorb water, allowing them to grow. Roots of vegetation bind the sand in the dunes together.
The vegetation has since taken over the dunes here, giving a sight of green along the beach, as far as the eyes can see. This is helped as the dunes give humus (nutrients) to the dunes. This has allowed an ecosystem to thrive here, so where possible, please avoid treading on the plants on the dunes.
Questions
To log this EarthCache, please send the answers to the following questions by email or message. Only answers that are drastically incorrect or photos that reveal answers will be deleted.
1. Take a handful of sand from the beach. What do you notice about it in terms of grain size, colour, what it is made up of, etc. Also, what is unusual?
2. What difference is there between the sand at the beach and the sand at/around the dunes and what do you think causes this difference? (A comparison between BEACH and DUNES waypoints would be ideal)
3. On a scale of 1 - 10, how fertile are the sand dunes here? (1 being not at all, 10 being the most).
4. TO PROVE YOU VISITED: Please add a photo of you or your GPS or an item of yours at GZ with your log
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If you would like to add more caches to this series, please feel free to do so!
Please contact heartradio through his profile first so that he can keep track of numbers and avoid duplications. Caches can be any type except Traditionals
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As this is a Local Nature Reserve and Biological SSSI, permission has been sought for this EarthCache.