🏴
This EarthCache takes you to the base of The Scotsman Steps, which is a geological delight of Scotland. There is plenty to see on the steps, though this EarthCache just concentrates on one aspect of geology.
The below photograph shows where to look.
🤔 What are we here to look at?
We are here to look at Tension Gashes.
🤔 What are tension gashes?
These are the evidence of the rock being under stress. A rock is only able to resist a certain amount of stress, before it starts to display signs of stress.
For example, imagine chocolate bar, in its resting state it appears perfect, though start to bend it, and eventually lines appear the more it bends. It is all to with how ductile an item is, this means how resistant it is to stress before signs of deformation develop.
➡️ Types of Tension Gashes.
🟦 Straight. These are simple fractures in the rock, that are straight lines.
🟦 Sigmoidal. These are S, or Z shaped, and occur when the tension gash rotates due to shearing forces.
🟦 En Echelon. This occurs when multiple tension gashes are arranged in a ladder like pattern, also described as a step like pattern.
STRAIGHT TENSION GASHES, ARRANGED EN ECHELON.
SIGMOIDAL TENSION GASHES, ARRANGED EN ECHELON.
This being an EarthCache, in order to log it, I ask that you complete the below tasks. Please send the answers to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile.
1. Please look at the indicated area, and explain what type of tension gashes there are here.
2. Why do they form?
3. Please have your photograph taken , or that of your device, or name , on the steps. Please do not reveal any answers to the EarthCache.