DLA2015 Sand Dunes, Cobbles and Pebbles
Hello Earth Cachers
As you walk towards GZ, from the Posted parking area you will notice the
beach go through a drastic change.
Close to the parking lot, the sand is just about absent, and it is mostly large Cobbles.
As you walk along the Cobbles turn to Pebbles and there is more sand.
Keep going and you will get to GZ, where even the pebbles are gone and you at a pure sand beach.
Not that I recommend it, but if you keep walking the beach will disappear and the sand scrubs take over.
Lets start of with Classifications of Rock Sizes, of Grain Sizes.
If you look at the lay out of the surrounding area, you will see it is a "U" shaped inlet.
As the waves come crashing in, they sweep the shore line From East to West.
It's hard to see, but on really wavy days you can witness it.
This effect over 1000's of years not only carved out this inlet, but has moved the Cobbles/Pebbles
Please Note the Smoothness of the Cobbles and Pebbles, caused by years of moving and tumbling
by the waves.
On Windy days you can see sand being carved and blown along the shore line as well.
There are 2 locations where the vegetation has totally been removed and you will notice it is on the same North Westerly angle
as the motion of the water and wind movement.
Now lets look at the Formation of the sand Dunes at GZ
A dune may be simply defined as a mound or ridge
formed by the deposition of sand.
These geologic landforms develop when an abundance of sand combines with wind,
vegetation and geography. .
The dunes of The Back Beach are comprised of fine sands, and as a result,
they are particularly vulnerable to
erosion—from storm waves and from wind.
People’s indiscriminate use of dunes can damage
or destroy thousands of years of geologic processes in one instance.
For the reasons listed above in the last line, I must insist you DO NOT
Climb the dunes or go atop the hill.
So from the information I have given you above, and from what you will see
upon arriving to GZ you should know a little more about Dunes,Cobbles and Pebbles
Please send me the answers to the 4 following questions Via my Geocaching profile.
1) Using the grain chart above, are there any boulders found on the beach?
2) What is the average size of the rocks at the parking area, compared to GZ?
3) On the day you visited, is there any evidence found in the sand of the wind direction
If so, what was it.
4) Approximate the distance from the water's edge to the top of the Dune, where there is little vegetation
REMEMBER, DO NOT CLIMB
BONUS CHALLENGE
Totally optional
Wade out into the water,
How deep is it about 20 meters out?
Is ther Pebbles or Cobbles in the water?
Take a photo from the water water, but not of GZ
Remember with all my Earth Caches, the idea is to learn a bit of Geological history and have fun
It IS NOT to cause you grief trying to give perfect scientific answers
Just do your best.
This Geocache is being hid for the DLA2015 MEGA Event GC5FPJB,
Do not seek until 9am on Saturday August 22nd, 2015