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The promenade in Weston-super-Mare underwent significant redevelopment, which was completed in 2010. However, the original promenade has been in existence since the town's development as a seaside resort in the 19th century.
Tafoni are unsual patterns of weathering in a rock
Tafone (plural Tafoni) are ellipsoidal, bowl-shaped, natural rock cavities. These cavernous weathering features include tiny pits, tennis ball sized cavities, truck-sized caves, and nested and cellular honeycomb forms.
Tafoni typically develop on inclined or vertical surfaces and occur in groups. These exquisite and fascinating cavernous weathering landforms are present on the surfaces of many different kinds of rocks located in a multitude of geographic regions around the world.
Since the late 1800s, more than 100 research articles have been published in numerous languages on this geomorphic topic. Tafoni development and evolution is puzzling and continues to arouse curiosity.
How Are Tafoni Formed? Several theories have been presented to explain tafoni formation, including: freezing-thawing, wetting-drying, salt weathering, intratidal, as well as supratidal weathering, but exactly how or why tafoni occurs can vary greatly depending on who you ask, and/or the rocks and location it is found.
One thing that is widely agreed upon is that generally some form of salt is involved.
Is salt essential? The typical occurrence of tafoni in high saline environments (e.g., arid deserts, intertidal areas) is strong evidence that salt likely plays a crucial role in tafoni formation. However, the explanation of salt as a weathering agent is incomplete because it does not account for why tafoni develop in some but not all coastal rocks. Accordingly, in addition to salt, researchers emphasize additional controls and weathering agents that work to create tafoni.
Salt weathering also called honeycomb weathering, fretting, cavernous weathering, alveoli/alveolar weathering, stone lattice, stone lace or miniature tafoni weathering, common on coastal and semi-arid granites, sandstones and limestones is the most common explanation. It occurs when salt collects on the surface of permeable rocks, usually by ocean waves, mist, or wind. As the saltwater evaporates, it leaves the salt behind. The salt works its way into the rock pores, where it crystallizes expanding by 1% to 5% and pushes the pores open further. These enlarged rock pores become susceptible to additional weathering. After a significant amount of time, the weathering becomes noticeable in the form of tafoni.
LOGGING REQUIREMENT - (MUST BE ATTEMPTED)
(YOU SHOULD RESPOND FOR YOURSELF - 'GROUP' ANSWERS WILL NOT BE ACCEPTED)
In order to claim this earthcache you must answer the following questions:
1. On one capstone at the SEA WALL, describe the tafoni (size, shape, amount as a percentage)
2. Do you find tafoni on all sides of the rock? Why do you think that is?
3. Is the phenomenon confined to just one capstone ? Do you see any tafoni elsewhere? If so, describe what you see.
4. After your visit to this location, and reading the information on the cache page, how do you think the Tafoni here were formed? Suggest a timeframe.
5.Highlight the differences between the capstone, the sea wall and the capstones on the other side of the promenade
6. Post a picture of yourself or a personal item at the sea wall with one of the pier in the background that shows you visited the site. THIS IS REQUIRED EITHER WITH YOUR ANSWERS OR IN YOUR LOG.
THE PHOTO IS INCLUDED WITH YOUR LOG MOST DEFINITELY DO NOT SHOW THE SEA WALL CAPSTONES. Nor should you post answers in your log.
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You should carry out these educational tasks as required by the EarthCaching organization, as a condition of logging the cache. Logs that do not adhere to these guidelines will be deleted without notification. See http://www.geosociety.org/earthcache
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