Written by the TreasureGuide for the exclusive use of treasurebeachesreport.blogspot.com.
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| Source: http://www.seafriends.org.nz/oceano/beach.htm |
I won't add all of the details to this discussion for a while. The basics will be helpful enough.
I also recommend reading the web site that is the source of this diagram. It only talks about beach building and erosion though. I'll add details about the movement and distribution of other objects such as coins.
The lines showing the high and low tide change position of course, sometimes dramatically, and the water can get all of the way up to and over the rear dunes at times. That can reshape the beach, including the fore dunes and everything in front of it. At times there will be cuts, cliffs and dunes. and then they'll all be smoothed out and replaced again.
In the top part of this diagram it shows how sand is borrowed from the beach and the sand is dragged down into the water and deposited in shallow water. Notice how the waves break on top of the newly formed bar.
Note also that during the storm sand comes in from deeper water and is dragged into the water from the beach (sometimes I might add). There are more details that I won't get into now.
I will however mention my personal observation concerning the angle of the water being very important in determining how the sand and other items move.
The important thing here is that not only does sand move, but also according to the force of the water and other factors, other items such as coins also move. Each type of item, as I explained yesterday, is different in terms of how much force it takes to get it to begin moving and how much force it takes to keep it moving. Those things, along with other factors, such as the item's shape and weight and how deeply it was buried to begin with, will determine how the item is moved and where it ends up. These are the forces that create coin lines and holes.
One of the reasons I discourage use of discrimination is that if you are not detecting a variety of different kinds of items, you will not be getting important information that tells you where different kinds of items are being deposited. If, for example, you are finding thin light pieces of aluminum or whatever, that tells you something important.
A coin hole will normally have items that are more difficult to move near the center of the hole, for example, lead sinkers, quarters or gold rings. If you are in an aluminum or zinc penny zone, you are not in the sweet spot, assuming that there is one. The information provided by the junk you find can help direct you to the sweet spot.
You might remember the experiment that I did to illustrate how the shape of an object as well as the objects weight helps determine how the object will be moved by water. (See my 8/5/13 post.)
The bottom part of the above diagram shows how the sand that piled up after the storm gets redistributed again. Some of it goes back up on the beach and some out into deeper water.
On the Treasure Coast right now there is one beach where you can see a large sand bar just off shore that was created not by any significant storm, but by beach renourishment sand washing out into the water.
If I was talking about shallow water hunting I would point out some important details here, but I'm going to stick to beach detecting for now.
I want you to see the news about a new fossil discovery so I'll leave off on my Reading Beaches 101 topic for now.
A historic new discovery of fossils has been made which reveals many that have never been previously seen. New species are being discovered as well as new details of previously known species.
Here is the link. If you like fossils, you'll love this.
http://www.rom.on.ca/en/blog/mighty-burgess-shale-fossil-site-discovered-in-kootenay-national-park
I wonder if some or all of those fossils couldn't/shouldn't stay in situ? Why cut up and remove examples that can be made into casts, photographed, or replicated and documented in various forms be cut out and removed to a remote location. Is it so some museum or paleontologist can possess them? I'm sure that some will say so they can be better studied back at the lab, but I don't know how true that is. Perhaps if they stayed in situ they could be better studied in the future with the new technologies of the future in the location and situation where they were found. A similar argument about archaeological artifacts is sometimes made. They say they are better off being protected in situ for study in the future when there are new methods of study. I suspect that someday these fossils will be able to be viewed using new technologies exactly where they were found while still encased in the rock. Just raising some questions here applying the logic and ideas that I've heard from academics before.
All of that is entirely different from beach found items which are already dislodged from their context and are undergoing tumbling and the unrelenting destructive forces of nature at the oceans edge.
On the Treasure Coast today the surf is around three feet, which is a touch higher than expected. The next couple of days expect a slightly calmer surf. Beach detecting conditions remain poor.
Happy hunting,
TreasureGuide@comcast.net
