Barsø Rocks
A few of the large pieces of Rock on the beach.
North of Østerklev (on the east side of Barsø) you will find some very special rock blocks, both on the beach and on the slope.
These are formed when carbonated water on the surface has dissolved the lime there, and carried this lime further down into the layers in the slope. Later, this lime has been precipitated and has thereby glued it all together into one solid mass. Thats how the distinctive rock blocks have been founded. It's almost like when stalactites form - you know - the stalagmite and stalactite thing - just without anything dripping.
The rock blocks belong to a specific mountain type.
Examples of where the mountain types may have their origin.
3 different main types of rock
Geologically, the rocks are divided (classified) into 3 main types, according to how they were formed: igneous, sedimentary or metamorphic.
Igneous rocks
Magma is liquid rock mass from the earth's interior. When such magma cools down, it will solidify into a solid mass of rock - which in turn can be divided into 2 subgroups:
By rapid cooling, day rocks are formed (also called extrusive or volcanic rocks). These are typically formed at the surface in connection with volcanic eruptions and have a very fine grain size (less than 1 mm).
By slow cooling some distance down in the earth's crust, deep rocks are formed (which are also called intrusive or plutonic rocks). Due to the slower cooling, this subgroup forms coarser-grained structures, with larger, distinct crystals (over 5 mm in size).
Sedimentary rocks
These rocks are typically formed by smaller parts of rocks, organic material or chemical precipitation being deposited on the earth's surface. Many sedimentary rock types also have a clear layering.
Clastic sedimentary rocks are formed by dissolving rock fragments such as sand, clay, gravel or lime, is transported and deposited by the rivers, seas or winds that prevailed on the earth's surface at the time of formation. After deposition, the fragments (sediments) are cemented together by a binder (cement), which typically consists of silica or lime.
Biogenic sedimentary rocks consist of grains of calcareous shells from dead organisms, chalk, but can also be e.g. coal. which is similarly deposited and cemented into a cohesive rock mass.
Chemical sediments consist of material precipitated from an aqueous solution (in oceans or lakes). An example of this is gypsum.
Metamorphic rocks
These are formed through a transformation (metamorphosis) of other rock types. This alteration process is caused by changes in pressure and temperature conditions, where the minerals and structure of the parent rock are completely or partially changed, forming a new rock. The characteristics of the individual metamorphic rock are therefore highly dependent on the source rock and the pressure and temperature conditions it has been exposed to. Metamorphic rocks are typically found where the earth's surface has been subjected to major deformation such as mountain range folding.
Here it is very good to study the cliff or "rock" a little better.
Logging this EarthCache:
By the coordinates, you must answer the questions below.
You have to sent the answers to me either as a message or email - BEFORE you log the cache online.
You are welcome to log online before you get an answer from me, but the answers must be sent before you log the cache online. If there are problems with your answers, I will contact you.
The questions are answered based on the 2-3 large blocks on the beach and the hard cliff.
- What type of mountain/Rock is this?
- If there are subgroups of the mountain type - which subgroup is it?
- Justify your answers by describing a block/slope and use some of the terms in the description of the mountain types above.
- Do you know some of the stored stones? Which ones?
- There are 3 large blocks on the beach. What is the circumference of the largest of these 3 rock blocks?
- Can you see signs indicating whether pieces of the cliff breaks off where this mountain type is found, often (annually) or rarely? Justify your answer!
I will be happy if you attach a photo from the area in your online log, with or without you. It must not be a spoiler photo and reveal answers in relation to the tasks.
Enjoy the area.
Happy caching - micbladt c",)
|