Nobby's Honeycomb EarthCache

Nobby's Beach, an iconic artificial landmark in the city of Newcastle is home to a rare geological process.

Honeycomb Rocks can be found along the esplande leading out to Nobby's Headland.

To understand the process of Haloclasty, we must first take a look into the formation of sedimentary rock. Over thousands of years, the Hunter River has been depositing layers of sand, clay and other materials on the sea floor. Accompanied with an adhesive, water, and the shear weight of the riverbed, the layers have compacted, creating Sandstone.

Honeycombing is a form of weathering, powered mainly by salt heaving. Salt carried into the supratidal zone (area just above the high tide mark) from Sea Spray lands on the soft sandstone rocks. The moist Sea Spray then infiltrates into the rock. Heat, generated by the sun, allows the salt water to evaporate thus leaving a slight pore in the rock where the salt crystal was.

Other natural processes such as wind and rain, aid in the erosion of the sedimentary sandstone. The wind carries sand particles into these combs and in a circular motion, the wind widens them, thus enlarging the diameter of the Honeycombs.

Over time, this process has duplicated itself thousands of times, creating "Honeycomb Rocks."

Please be mindful of the surrounding environment...please don't climb on the rocks or damage them.

To log this Earthcache, please EMAIL me the answers:

(Assuming you are facing East towards the beach)

1. Put your finger in the TOP RIGHT hand Honeycomb. Approximately how deep is it?

2. What is the approximate surface area of BOTH rocks. Please answer with working. eg: 4m² + 6m² = 10m²

3. What are the colours of i) The Sandstone ii) The sand inside a Honeycomb ?

4. OPTIONAL: Please provide a photograph of you (or GPS) near GZ

Please feel free to log your visit online before receiving confirmation of your answers from me, as I will contact you if there is a problem with any of them. If your email is not received within a timely manner of your online log...then your log will be deleted.

Thanks to Chippyroo for proofreading!!!