This cache will take you the tombolo that connects Tanjung Tuan to the Malaysian peninsula.
Type of Earthcache: Deposition (deposit of sediment).
Tombolo at Tanjung Tuan
Some visitors might have noticed there is a body of water on both sides of the approach to Tanjung Tuan. If you are not aware that you are standing on a tombolo, it is easy to mistake these as two separate bodies of water, while in fact you are looking over the Malacca Straits on both sides, and thus they are the same. Once you realise that you are in fact standing on a tombolo, you also know Tanjung Tuan is essentially a tied island connected to the Malaysian peninsula by the same tombolo you are standing on.
Formation
A tidal island is a piece of land that is connected to the mainland by a natural or man-made causeway that is exposed at low tide and submerged at high tide. A tombolo is a deposition landform in which an island is attached to the mainland by a narrow piece of land such as a spit or bar. Once attached, the island is then known as a tied or tidal island.
Tombolo's are more prone to natural fluctuations of profile and area as a result of tidal and weather events than a normal beach is. Because of this susceptibility to weathering, tombolos are sometimes made sturdier through the construction of roads, parking lots or other developments (as is the case at Tanjung Tuan). The sediments that make up a tombolo are coarser towards the bottom and finer towards the surface. It is easy to see this pattern when the waves are destructive and wash away finer grained material at the top, revealing coarser sands and cobbles as the base. Sea level rise may also contribute to accretion, as material is pushed up with rising sea levels.
True tombolos are formed by wave refraction and diffraction. As waves near an island, they are slowed by the shallow water surrounding it. These waves then bend around the island to the opposite side as they approach. The wave pattern created by this water movement causes a convergence of longshore drift on the opposite side of the island. The beach sediments that are moving by lateral transport on the lee side of the island will accumulate there, conforming to the shape of the wave pattern. In other words, the waves sweep sediment together from both sides. Eventually, when enough sediment has built up, the beach shoreline, known as a spit, will connect with an island and form a tombolo.
Aerial view of the tombolo at Tanjung Tuan.
View on Google Earth/Maps
(Source: Google Earth/Maps, September 2017)
How to claim this EarthCache?
Send me the following;
1. The text "GC7C74Z Tombolo of Tanjung Tuan" on the first line.
2. The answers to the following questions;
- From the given coordinates (intersection), how might you recognise you are on a tombolo?
- List at least 3 differences between both sides of the tombolo that allow you to determine which is the stoss (open) and which is the lee (protected) side.
- Describe the sediment/sand on each side of the tombolo (size, colour, ...). Explain why it differs.
- The length of this tombolo is about 410 metres, but how wide is it?
- Should the anchor island erode away; how do you see this tombolo evolve?
3. Provide a photo of yourself or a personal item to prove you have visited the site. *
References
* Effective immediately from 10 June 2019, photo requirements are permitted on EarthCaches. This task is not optional; it is an addition to existing logging tasks! Logs that do not meet all requirements posed will no longer be accepted.
For additional information, visit; Geosociety.org, Geocaching.com Help Center and Geocaching.com Forum.
Finding the answers to an EarthCache can often be challenging, and many people tend to shy away from these caches because of this. However, it is my opinion that geocaching is also meant to be a fun family experience that simply aims to introduce interesting and unique locations such as this one. Flexibility on logging requirements, however, can only be applied if it can be established that you have actually taken the time to visit the site. For this reason, a proper log describing your adventure accompanied by a good number of photos would be much appreciated.
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