This cache will lead you to an interesting geological phenomenon in Santa Maria island.
Thanks to the dimensions of the ground at the GZ, this area has the effect of a viewpoint of the phenomenon itself.
In this area you can observe an interesting geological structure called Columnar Jointing.
The formation of prismatic columns occurs during cooling of the lava from a volcano. When the lava cools the tension caused by thermal contraction exceeds the tensile strength of the rock, leading to fracturing. The formation of pentagonal or hexagonal prisms is motivated by the stability of these geometries in terms of a rupture surface. The development of the columns is generally perpendicular to the surface cooling. This usually coincides with the top or bottom of the draining area, and for that reason the observation of vertical structures is quite common. |
 |
 About the Earthcache
To claim this earthcache you need to fulfill the following tasks:
a) what is the number of columns you can observe?
b) what is the approximate height of this phenomenon?
c) what is the colour of the columns?
d) what is the name of the rocks that the columnar jointing is made of?
|
|
 |
Also, and despite being optional, please take a photo with your GPS in the stage you prefer with the phenomenon in the background.
Send the responses via my geocaching profile and enjoy the view.