Cause we change Rottnest Island, Western Australia, Australia
By Rottnest Islander on 11-May-15. Waypoint GA7210

The eastern end of the causeway that divides Herschel and Government House Lakes is a perfect vantage point to discover the shoreline features, notches and visors that are evidence of sea level change.

Earth Sciences Lesson: Geological Material

Shorelines are carved over time, leaving unique and oftentimes spectacular shoreline features. A wave-cut cliff is a steep rock face created by the eroding action of waves. As waves continue to hit the supporting rocks of the cliffs, a notch is carved into the cliff face. Rocks overhanging the erosion weaken and crumble, causing the cliff to retreat further inland.

Further Reading:

Guidebook to the Geology of Rottnest Island by Phillip E. Playford.

Questions:

1.  Estimate the measurements (answer to nearest 10cm) from the ground to the following features:

A)         Upper level platform

B)         Intermediate notch

C)         Lower notch

Instructions and How to Verify Your Find

Once you complete the “Cause we change” EarthCache requirements you can post your find without delay, as per the EarthCache guidelines. You will, however, need to verify your find by sending me a message with the GC code and cache name on the first line and provide your answers to the questions listed below, otherwise your log may be removed.

Adhering to the EarthCache guidelines, please be careful not to include any detail in your log or photos that may assist others in answering the questions without actually visiting the sites and carrying out the fieldwork.

This EarthCache presents a good opportunity to practise CITO (Cache In Trash Out), so please bring a rubbish bag and help save the environment. Take a photo of the rubbish you collect along the way and include in your log for bonus geo-karma points!

Make sure you stick to the designated paths and leave no trace. Please do not interfere with the geological material, vegetation or wildlife – the tasks can be completed without the need to damage the environment.