Near Grafenau there´s a rocking boulder which weighs several tons (according to our own calculation it should weigh approximately 20 tons). With some efforts and the use of of the right pressure point, it can be moved a little bit.
Very surprising however, is the fact, that this rocking boulder is not indexed by the "Bayerisches Landesamt für Umweltschutz" yet, although one of the tasks of this government agency, is to register such objects.
Link for "Bayerisches Landesamt für Umwelt"
Link zu den bislang erfaßten Geotope im Landkreis Freyung / Grafenau
So, it´s the ambition of this Earthcache to determine the dimensions of this rocking-boulder and then forward the information to the "Bayerisches Landesamt für Umwelt". Perhaps it will be added to its database.
But first of all, we would like to provide you with some information, how this rocking boulder came into existence.
Well, it´s a result of a so called woolsack weathering which gave this boulder its shape by several processes of mechanical and chemical weathering and erosion.
First, a massive rock, lying underneath the surface was split into cubes by physical means. Quite often, two of this means are water and frost = physical weathering.
In the next step, there´s an intrusion of rainwater enriched with oxygen, carbon dioxide and other aggressive substances. In the beginning the cubes will be corroded at the corners and angles. The rounded shape is now formed ( = chemical weathering) - underneath the surface - that's important to know!.
In the next step, the soil erodes, especially by means of water and wind. What rests are the rounded rocks which stay layered one upon another. In the case of this rocking boulder, it´s the very rare case to find one single boulder lying upon another single boulder.
The following picture should give you an impression of these processes
And these are the questions to be answered, to log this cache:
Go to the aforementioned coordinates which mark the rocking boulder.
1) which length and biggest width has the base of this boulder.
2) measure the length of the rocking boulder
3) measure the biggest width and biggest height of the rocking boulder
4) take a picture of you and/or your yardstick at the rock and post it with your log
Please send your solution to question 1) to 3) to:
or to our account at geocaching.com
Please don´t write the answers into your internet-log at GC!