Lac Assal, Really Deep EarthCache
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This is the first Earthcache in Africa! Besides being one of the really hot places in the World you should approach this location with a 4 WD. The "roads" of typical African condition. But what makes this point really outstanding is the elevation!
The Lac Assal in Djibouti is located at the deepest point in Africa with an altitude of approximately 155 m below sea level. That makes this point the second deepest point on the surface of the Earth after the Dead Sea. The Lac Assal is the lake with the highest salinity worldwide. It has a salt concentration of approx. 34.8 % which is 4 percent higher as the salt content of the Dead Sea. The lake receives it water from subterranean springs which are fed from water of the Indian Ocean. Furthermore the salt content is increased by the high evaporation rate at this place (lots of sunshine and hot climate). The lake is situated within the African rift valley where the initial stage of the separation of continents can be observed. It is like a rubber band that you tear apart at its ends it will become thinner in the middle and at one time it will break. Here at the Assal Lake the stage where the middle becomes thinner is present and being thin the hot molten rocks situated below the earth’s crust have it much easier to get to the surface what causes the volcanic activity in this region. Here comes a more scientific explanation: The East African rift system is a divergent plate boundary created through the rifting and separation of the African and Arabian tectonic plates that began around 35 million years ago in the north, and by the ongoing separation of East Africa from the rest of Africa along the East African Rift, which began about 15 million years ago. It has reached locally the stage of continental rift, with attenuation (thinning) of the continental crust and lithospheric mantle. High surface heat flow (proportional to the temperature gradient) and volcanism testify that the asthenosphere is rising underneath the lithosphere. In the near future (well by means of geologist! You do not have to hurry as you have at least a couple of million years time for your visit!) the mountains separating the Indian ocean and the Assal Lake will be torn apart and the whole area flooded. Once you visit this place you have to perform a little experiment that need a bit of preparation from your side. You have to collect a water sample (use a 1 liter bottle of any kind / if you use a different volume correct your weight measurement so that it is equal to what 1 l would have had) and take it to the place you are living (or the hotel). There let the water evaporate and state the weight of the salt you received from your water sample in your email to me. Of course you should provide photographic evidence for your experiment! Even so it seems obvious, transfer the water from the bottle into a pot of some sort to evaporate the water otherwise it will take ages (alternatively you can heat the water as well). Furthermore as a proof of your visit to the Assal lake please post a photographic evidence that shows you, your GPS with the coordinates and your height readable and the bottle of water you collected for your experiment. Logs with different approaches or not complete photographic evidence might be approved as long as they were discussed with me via email. But generally speaking: No experiment, no email, no photo (of you at Lac Assal and of the result of the experiment!) = No Log! You HAVE to do ALL Three! You do not have to go exactly to this position everything close to the lake and with a negative altitude will be fine! Faked Photographs will lead to the deletion of your Log! You can provide the answers (and log the cache) either in english or german, (that might help some tourists). PLEASE do sent your email address along so that I can answer! If you do NOT send your EMAIL along I will NOT ANSWER! Free counters
Additional Hints
(Decrypt)
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