This sandstone is located in the Sydney basin, which originated from sediments between 290 and 200 million years ago. 
The Sydney Basin stretches from Newcastle in the north to Durras Lake on Batemans Bay in the south. From Durras Lake it is as far as Ulan near Mudgee, and westwards to the Blue Mountains. The northern border leads along the Liverpool Range to Muswellbrook. Partially, lava entered the cleft of the sandstone layers and solidified into lava rock. The layers of Hawkesbury sandstone are up to 200 meters thick. The Hawkesbury sandstone is yellow to brown colored with fine to medium grains. The quartz content is different depending on the rock layer, it can be up to 95 percent. Feldspar is scarce. Up to 10 percent lime as well as clay as a binder in this rock were found. The Hawkesbury sandstone is very weather-resistant with high quartz content. The Sydney rock engravings in the Ku-ring-gai-Chase National Park have been endemic and have survived to this day. This is due to the fact that this sandstone has a high quartz content and is therefore highly weather-resistant. But it does not last forever. What is weathering?
Definition
Weathering is the breaking down of rocks, soil, and minerals as well as wood and artificial materials through contact with the Earth's atmosphere, waters, and biological organisms. Weathering occurs in situ (on site), that is, in the same place, with little or no movement, and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity and then being transported and deposited in other locations.
Wich classifications of weathering processes exist?
1.) Physical weathering
This is a purely mechanical destruction of the rock:
- During wind weathering, the grinding effect is increased by the presence of loose particles
- In the area of frost weathering, damage, sanding and flaking occurs in the surface area with a frequent frost / thaw change, as water will expand by 10% during the transition from liquid to solid state.
- In the case of salt weathering, a build-up of hydration pressure and crystallization pressure occurs during salt formation in the pore space since water accumulation is associated with volume enlarging.
-Thermal stress weathering results from the expansion and contraction of rock, caused by temperature changes. For example, heating of rocks by sunlight or fires can cause expansion of their constituent minerals. As some minerals expand more than others, temperature changes set up differential stresses that eventually cause the rock to crack apart.
2.) Chemical Weathering
Chemical weathering changes the composition of rocks, often transforming them when water interacts with minerals to create various chemical reactions:
- Mineral hydration is a form of chemical weathering that involves the rigid attachment of H+ and OH- ions to the atoms and molecules of a mineral. When rock minerals take up water, the increased volume creates physical stresses within the rock.
- Hydrolysis takes place when acid rain reacts with rock-forming minerals such as feldspar to produce clay and salts that are removed in solution. The only common rock-forming mineral that is not affected is quartz, which is a chemically resistant mineral. This is why quartz and clay are the two of the most common minerals in sedimentary rocks.
3.)Biological weathering
In biological weathering, microorganisms cause damage to the rock by various reaction processes:
Living organisms may contribute to mechanical weathering (as well as chemical weathering, see 'biological' weathering below). Lichens and mosses grow on essentially bare rock surfaces and create a more humid chemical microenvironment. The attachment of these organisms to the rock surface enhances physical as well as chemical breakdown of the surface microlayer of the rock. On a larger scale, seedlings sprouting in a crevice and plant roots exert physical pressure as well as providing a pathway for water and chemical Infiltration. Trees put down roots through joints or cracks in the rock in order to find moisture. As the tree grows, the roots gradually prize the rock apart. Even the tiniest bacteria, algae and lichens produce chemicals that help break down the rock on which they live, so they can get the nutrients they need.
What does this have to do with the sandstone rocks in Shark Bay?
Honeycomb weathering
The honeycomb weathering in the sandstone is not a rare phenomenon. 
It arises chiefly by chemical influences, and not, as was formerly assumed, by wind erosion. The percolating water transports the acid through the rock. Especially when it hits a clayey interlayer and does not penetrate further downwards, it moves horizontally through the rather loose sandstone. Where it emerges from the rock, the chemical reaction that produces this form of weathering begins. The water can evaporate. On the surface of the rock, salts are precipitated, forming small crystals that break the sandstone and thus accelerate the weathering. At the same time, the solidification of the rock occurs under the influence of silica. Cave-like structures develop over time. The typical honeycomb pattern is created. We usually observe these processes on steep walls or overhangs. If the honeycombs are of dark color, and the ground is not covered with bright, loose sand, the weathering has come to a rest. If one finds bright spots, the chemical weathering is still in progress.
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1.) Examine the size of the honeycombs. Estimate the sizes of the largest and the smallest you can see!
2.) Is the weathering process still active here, or do you think it has stopped? Give reasons for your opinion.
3.) Can you find other weathering processes here? If yes, wich?
Source directory:
-geolsoc.org
-wikipedia
-Foto by my own