To claim a find you will need to visit the location given, read the description below, find a few pieces of coal and answer some questions.
To submit answers you may email or message the answers to me and you may claim your find and send your message together.
At this location you will find bits of black material on the beach. Some is the size of small grains of sand and collects in swathes. Some pieces are much bigger and I even saw some pieces larger than a house brick.
These black deposits are mostly sea coal and some may be jet
In the north east and Yorkshire Coast beach-combing can be very rewarding. The coast has strata is full of fossils and the boulder clay also has fossils in it ripped from the rocks by the glaciers coming down from the North during the ice ages. The general movement of material along the north east coast by the sea is also from the North to the South. This is the direction of the most powerful waves.
Jet and coal is found from North of Whitby and can be found all along this coast. Similarly Amber is mainly found around the Baltic and the ice sheets carried it down and dumped it in the boulder clay around the North sea so can probably be found anywhere south of here where the main deposits of boulder clay start on this east coast.
However it is important to remember that most of the time there is very little of interest washed up. It is very condition dependent. You need a good sustained gale force 8 or above with some East in it. Northerly gales have the most powerful waves and erode the cliffs fastest particularly if the tides are big but South Easterly gales often halt the southerly movement of material and throw it up on the beaches. Again each individual beach has its own conditions when material is thrown up. Most stuff will wash up as the gale starts to subside or swing round to the west.
The best clue that conditions are good is the presence of patches of weed and black coal on the beach. Sometimes the weed can be feet thick covering a huge area of beach. These are good areas to look for amber and jet when the sea has sorted it a bit. Amber is far rarer than coal and jet. Finding fossils in the cliffs is probably best after a spate of fast erosion i.e. big northerly seas on a spring tide.
Even if conditions are poor for beach combing as they are in much of the summer you can still find fossils among the piles of pebbles and in the rock strata itself.
Whatever you are looking for remember that the sea sorts things into similar size and density. So if you find one look in the same area for others. Often within a few yards you will find some more.
The focus of this EarthCache however is coal
Sea coal is like no other type of coal. In appearance it's sparkling clean and shining jet black. Fist size chunks are like large black diamonds. In the fireplace it can be ignited by heating with the very minimum amount of kindling. It appears on beaches because as storms as mentioned above churn up water above exposed seams it breaks off and action of the waves will wear down the sharp edges leaving a rounded pebble of coal. This action of moving the cola about and wearing it down is called weathering.
The coal seams of the some coal mines extended out under the sea and although it was very good coal it did not have the properties of sea coal. Mined coal must first be heated to a relatively high temperature before it will give off gas that will ignite. When mined coal is completely spent there will be a fair amount of residual ash. The process of combustion of mined coal also generates a considerable amount of smoke and soot. Hence the nickname of Auld Reekie bestowed on the town of Edinburgh before the days of North Sea oil.
Sea coal has quite different properties. As sea coal is first heated it enters a semi liquid stage and bubbles as its gases ignite. It burns with an extremely hot flame and produces a clean flame that gives off a far greater amount of heat than mined coal. Burning so cleanly there is very little residual ash or chimney soot or smoke. When the fire has finally burned itself out, what's left in the fireplace is only a very small amount of powder.
Wherever you find coal washed up you can normally find jet . A very tiny percentage of the black stuff is jet and even less of it is good quality jet. The way to test it is to rub it on sand paper (or a sandstone pebble) and if it marks black it is coal, if brown it is jet. However there are also different grades of jet. Good quality jet has a shiny appearance straight out of the sea whereas some looks quite dull. After a while you get your eye in as the shape is often quite different to coal, flatter. Anywhere you can get onto the beach or rocks in this area after an easterly gale is probably your best bet for finding jet sitting on a pile of washed up seaweed.
So I hope that gives you an explanation of why coal and jet is here and why it looks like it does.
Please use this to answer the questions below and remember to either message or email the answers to me when you log your find.
Questions
1 Please find a piece of the black stuff on the beach and describe it to me, tell me if it is coal or jet and how you found this out.
2 Please explain why there is coal/jet on the beach and why it isn’t the sharp and powdery product you could buy from a shop or coal seller for domestic use.
3 Please tell me the state of the tide when you visited
4 On the beach at the location given there are some large features that you wouldn’t expect to find, what are they?
If you do wish to add a photo please don’t include one that gives away the answer to question 4
Thank you for visiting the area and attempting this cache.
Happy caching
treboR