Note: This is a Difficulty 4 Earthcache, so the questions are a bit more involved. You don't have to give perfect responses, but you do have to demonstrate that you gave it a good try and learned something!
Djúpalónssandur - Black Lava Pearl Beach. Land of Elves, Trolls, and Faeries.
Folk tales tell us that Kerling (Troll Woman) and Karl (Troll Man) can be found in one of the rock formations on Djúpalónssandur. They are thought to be trolls that were turned into stones when they were caught in the sunrise As you walk down the trail to the Earthcache location, you will pass by many strange lava formations like these. Who knows what secrets and mysteries they hide? There is one special rock formation with a hole in the middle - a portal into Elven lands?
This area is also known for its very wild and unpredictable waves (getting close to the waves is very dangerous; please stay WELL back!) The wild seas have claimed many lives, including the lives of those from the shipwreck who's pieces have been left here. This area used to be a strong fishing community. Now, it is a piece of Iceland's protected and fragile nature. Make sure you stay on the marked trails and do not enter the realm of the elves or step on the very delicate moss that takes decades to grow back.
Earthcache Introduction
There are several remarkable features of this landscape. One is of course the thousands of small black lava "pearls", or stones. Another is the fascinating lava formations all throughout the landscape here; many covered in fragile moss. And yet another are the beautiful and strange basalt cliffs near the shore.
Rare type of lava
By now, you have probably travelled around Iceland somewhat and seen the characteristic basalt cliffs near many shores. The basalt cliffs at Djúpalónssandur are special, as they contain a rare type of lava: alkali. The alkali rocks at this location have a higher concentration of alkali content over silica.
Types of rocks
There are two types of rocks at this location: mugearite and benmoreite. These two types of rocks have a high silica content. Because this differs from the lower silica content of the alkali lava, you are able to see beautiful bands of colour in the grey lava, which are the mugearite and benmoreite. The dark (black) rocks represented parts of the lava that cooled very fast and are glassy, and the red lava represents oxidized lava that interacted with water.
Why are the basalt lava cliffs in Djúpalónssandur different than other parts of Iceland?
Lava eruptions occur in places that are along major rift zones that represent the locations of tectonic plate separation and crustal growth. Minor amounts of alkaline lavas can also erupt in areas that are farther away from the tectonic plate locations, notably along the Snaefellsnes Peninsula (and therefore Djúpalónssandur) which is >100 km from the tectonic plate rifts.
To log this Earthcache as found, you must send me the answers to the following questions. Old vacation logs are not allowed; you must have been physically present at this site after the cache was published.
Please take care to look around you very carefully as well as to read the cache page very carefully, so you can demonstrate that you have been at the location and learned something. Some of these questions are also to help me determine if you were actually at the Earthcache location, so make sure to study everything carefully! Remember to have fun and try your best. Every answer does not have to be perfect, you just need to try :)
1. Based on your reading of all the above information, what material do you think the small round pebbles of this beach are made of, and why?
2. Look closely at the colour of the pebbles and explain if it is the same or different than the colour of the basalt cliffs. Basalt cliffs are everywhere in Iceland. Any of the cliffs near the ocean shore in this entire area are basalt cliffs. Explain why you might think the colour is the same/different based on what you read above.
3. Head to any of the basalt cliffs near the ocean shore and examine them very close up. (Please do NOT get close to the water as the waves are VERY dangerous). Is the stone in the cliffs fine-grained or with thicker, bigger grains?
4. What is your hypothesis, based on what you read above, for why the grains might be fine or thick?
5. When you compare the texture of ANY oft he lava formations in the fields (these are all of the stone/rock formations that are large, covered in moss, that you see everywhere around you on the *land*, not on the beach), to the texture of ANY of the basalt cliffs near the ocean shore, what are the differences that you notice?
6. Concerning the differences you noticed in question 5, WHY do you think the basalt cliffs near the ocean are the way they are, given what you have read above?
7. At the posted coordinates, if you stand facing the small pool, with your back to the ocean, and look to your right, you will see what appears to be a man-made structure. Examine the stones used to make this abandoned structure - are they the same or different than the rest of the stones strewn on the beach? Think of colour, shape, and size.
8. When you look at the basalt cliff formations near the ocean, are the bands of oxidized lava at the TOP or BOTTOM of the formations?
9. Consider your answer from question 8 - why do you think the bands of red are in the location that you see them?
10. Mandatory: Provide a photo of your GPS, car keys, guidebook, Trackable or a "thumbs up" at GZ with the basalt cliffs or lava formations in the background.