The Drawing Room rocks are located on the southern Illawarra escarpment as part of the Barren Ground Reserve, these amazing unique rock formation have been formed over millions of years. This popular location offers fantastic sweeping views of the coastline and rugged escarpment with many visitor resting on the appropriately named “tables and chairs” to take in the vista.
The area is made up of Triassic period Hawkesbury Sandstone, the stone is notable for its geological characteristics and forms much of the Illawarra Escarpment. It is believed a freshwater delta (Ancient River) brought much of the grains of sand eastward millions of years ago. Rivers and creeks have since eroded the area to its present height and shape. The sandstone you see before you is said to be the cap-rock which controls the erosion of the Illawarra escarpment. Far beneath the sandstone lies igneous and metamorphic deposits.
The unique shapes of the rocks at the Drawing Room have been caused by weathering within the Hawkesbury Sandstone. Here the weathering has happened over a long period of time by a number of different actions which include wind, rain, cold, heat and the chemicals within the rain. The sandstone of the Drawing Room Rocks is of horizontal strata, so the flat table tops consist of stone made up of a harder more resistant mineral layer which has remained when the softer surrounding rocks have eroded.
Note: The walk to GZ can be steep, uneven and slippery at different times. Once at GZ there are numerous unfenced cliffs so please be aware of your surroundings and in no way damage or deface the rocks.
To claim a find on this earthcache you will need to answer the following questions:
- What period of time is represented by the Triassic period?
- At GZ you will notice the immediate area is made of large boulders which are different to those of the unique drawing room rocks, why do you think there is such a large difference between the large boulders and the smaller rocks when in some cases they are exactly the same rock?
- At the larger collection of unique rocks, how many flat top rocks do you count?
- In a south-westerly direction from GZ you will see a large flat top mesa. Do you think it is made of the same type of rock as where you are standing? Why has it or hasn’t it worn the same as where you are standing?
- Are these rocks going to remain in this shape over time? Why.
- (Optional) Include a photo of you and your GPS at GZ.
Email your answers to me via my profile, there is no need to wait for my response to log your find. If there are any issues with your answers I will contact you. Logs without emailed answers will be deleted.
reference: http://www.geomaps.com.au/scripts/drawingroomrocks.php