RICE PEBBLE BEACH
Access:
Rice Pebble Beach is accessible from a 4WD road (see trailhead waypoint) or the Bicheno foreshore walk. If you choose to walk you will see another similar but smaller beach nearby - see the waypoints.
GEOLOGY:
The unique thing about this beach is that instead of the usual fine sand found nearby, there are rounded quartz pebbles.
These "rice pebbles" are approximately 4-8mm in size:
They were formed by "quartz cooling in an amorphous (without form) and non-crystalline state as a constant size" (Manchester 2010, p. 90).
You can see the nearby adamellite boulders which is what the pebbles were made from. They contain large mica and feldspar crystals which are on average 5cm in size and also some veins of quartz.
Adamellite, also known as quartz monzonite, is similar to granite and sometimes described as a type of granite however contains less quartz.
Layering is also visible in some of the adamellite boulders.
QUESTIONS:
To log the EarthCache, you must answer these questions by messaging me through Geocaching.com or via the Send Answers button in the app (Note: Try not to email me through geocaching.com and use the message center instead - there’s a chance if you send an email it’ll get lost in my inbox). Please do NOT post your answers in your log! You may log the find before you have sent the answers, however please do so within a reasonable timeframe (ie 7-10 days). I will contact you if there are any problems.
1. Have a close look at the pebbles. Are they all opaque, or are some of them translucent or transparent?
2. To the left (towards WP2) you will see some granite/adamellite boulders with an unusual colour. What is this colour, and what do you think has caused it?
3 (optional). Take a photo of yourself at Rice Pebble Beach. Be sure not to spoil questions 1 and 2.
REFERENCES:
Wikipedia - Quartz monzonite [accessed 9 September 2018].
Manchester, P. S. (2010), Created from Chaos: a geological trail of 100 sites in Tasmania, Hobart, Tasmania.
Congratulations The Moor We Hunt... on your FTF!