Aeolian Calcarenites
During the Pleistocene era, the remains of marine creatures drifted to the bottom of the sea and were compacted into limestone, a sedimentary rock formation, along the West Australian coast. In the Perth region, this limestone was uplifted, broken up and much of it was worn down into sand. The sand was windblown and mixed with the broken limestone, forming irregular pockets of rock embedded in coastal sand dunes. The rock is known as Aeolian Calcarenites, reflecting the involvement of the wind and the carbonate contained in shell particles.
The offshore reefs and islands in the region are old sand dunes that were deposited during periods of lower sea level. Rocks along the coastline within the Tamala Limestone can be seen along the river and ocean shorelines. A number of interesting features are developed within exposures of Tamala Limestone across the Perth Region. These include rhizoliths, calcreted surfaces (beach rock), karstic features (e.g. sinkholes, caves), raised beaches, and elevated shoreline platforms.
When free from impurities limestones are white, but they generally contain small quantities of other minerals which affect their colour. Many limestones are yellowish or creamy, especially those which contain a little iron oxide, iron carbonate or clay.
Definitions
Pleistocene : The first epoch of the Quaternary period, between the Pliocene and Holocene epochs.
Aeolian : Relating to or arising from the action of the wind.
Calcarenite : Carbonate rock made from pre-existing rock through the processes of weathering and erosion, formed of particles of sand-grain size.
Rhizoliths : Root systems that have been encased in mineral matter.
Please email me the answers to the following questions:-
1. What kind of rock form is Limestone? (Igneous/Sedimentary/Metamorphic)
2. Looking East from the jetty, study the rocks you can see. What are their primary colours? Why are they this colour
3. Moving to stage 2, look closely at the limestone. Can you see any fossilisation? If so, what are they?
4. What is the diametre of the rhizoliths in the limestone? Is it consistent or do they vary?
5. Take a picture of yourself on or near the jetty and upload it with your found log.
Reference:
https://library.dbca.wa.gov.au/static/FullTextFiles/626630.pdf
In accordance with the guidelines, the procedure for logging an Earthcache is:
- Send me the answers.
- Log your visit. "People do not need to wait for permission to log your EarthCache."
Please note : If answers have not been received within 10 days, you will risk having your found log removed.