Tasks:
1. Describe the mineral veins, how wide are the veins, do they run straight or are they curved/branched?
2. What colors do the mineral veins have compared to the surrounding rock?
3. How do you think these veins were formed? Are the veins evenly distributed or are there differences?
4. Please take a picture of yourself or an object on site to prove your visit and post it with your log.
Log this cache as “Found it” and send me the answers to the questions to “silka03.earthcache@gmail.com”, my profile e-mail or via Geocaching Message Center. Not in your log!
You may then log immediately. I will contact you if something is wrong.
If there are no answers after 14 days I have to delete your log.
Have fun!
What we see on site
On Penneshaw beach there are striking white lines in dark rock. These lines are called mineral veins and are the result of geological processes that take place over millions of years. The veins usually consist of minerals such as quartz, calcite or other precipitates that are deposited in cracks and fissures in the rock.
Mineral veins are formed when:
1. cracks in the rock are formed by tectonic forces (e.g. pressure or stresses).
2. water containing minerals or hydrothermal solutions penetrate these fissures.
3. the minerals crystallize out of the water as soon as the temperature or pressure drops.
The white veins you see here are most likely quartz, a common mineral formed by hydrothermal processes. Calcite is also a plausible option, as it readily precipitates from carbonated water. These processes are typically associated with volcanic or sedimentary areas.
Scientific significance
Mineral veins provide important clues to the geological past of a place:
-They show that the rock has been subjected to stresses that have caused cracks.
-The composition of the veins reveals something about the mineral-rich solutions that once circulated through the fissures.
-They can also provide evidence of volcanic or tectonic activity in the region.
picture: https://www.dreamstime.com/photos-images/quartz-vein.html
https://en.wikipedia.org/wiki/Vein_(geology)
https://www.alexstrekeisen.it/english/meta/veins.php