Shipshape At Shiprock
Introduction
Welcome to Shiprock, a ship that never sailed. It is a striking sandstone formation along the Port Hacking estuary. This site is part of the Sydney Basin. The Shiprock feature and surrounding landforms expose Hawkesbury Sandstone, the famous golden-brown stone that dominates Sydney’s landscape.
Shiprock gets its name from its shape, which resembles the bow of a ship jutting into the waters of Port Hacking, in southern Sydney. It is not only a scenic landmark, but it is also part of the Shiprock Aquatic Reserve protecting underwater habitats. Below the surface it is home to an abundance of aquatic flora and flora. Above the surface, Shiprock provides a clear window into the geological story of the Sydney Basin. It tells the story of deposition, cementation, and erosion that shaped the Sydney coastline.
Location and access
Shiprock is located at the end of Shiprock Rd, Port Hacking in southern Sydney, NSW, Australia. Access is by a gate and staircase that provides a safe pathway between Shiprock Road and the water's edge. There is a platform around Shiprock, that allows you to get a closer look, and for divers and snorkellers to enter the water. Check the tides and regulatory signage at the reserve to confirm the activities that are permitted and prohibited. The gates are locked each evening. Opening hours are from Sunrise - 9.30pm.
SHIPROCK AS SEEN FROM THE PORT HACKING RIVER
Geology of the Region
The cliffs of Port Hacking belong to the Sydney Basin, a large geological structure formed during the late Permian to Triassic periods (around 250–200 million years ago). At that time, ancient braided rivers carried huge volumes of sand, silt, and clay across broad floodplains. Over millions of years, these sediments compacted and cemented into the solid rock we see today.
The dominant geological feature here is Hawkesbury Sandstone:
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A coarse-grained, quartz-rich sandstone.
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Often shows cross-bedding and ripple marks that reveal the direction of ancient river currents.
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Iron minerals within the sandstone give the rock its warm red, orange, and yellow colours.
SHIPROCK FROM THE STAIRCASE
Formation of Shiprock
Shiprock itself is a feature formed by erosion. It was once attached to the adjoining cliff face, but over time has eroded away to its current stand alone position. The headland that forms Shiprock projects into the estuary because it is made up of more resistant sandstone layers than the softer surrounding material that has eroded away. The sandstone here often shows cross-bedding, evidence of ancient river currents. Over millions of years, wind, rain, and tidal waters have worn down the weaker sections of the cliff, while Shiprock’s harder layers remained, leaving the distinctive “ship’s prow” shape.
Erosion continues to shape the features of Shiprock. Tidal action, wind, and rain continue to erode the cliffs, sculpting new shapes. Blocks may fracture and fall away, undercutting can occur along joints, and weathering creates rough textures on the rock surface. If you look closely at Shiprock you will see evidence of rock layers, folding and erosion along the walls of Shiprock.
Shiprock has a unique marine environment due to a combination of strong currents, clean seawater and complex rocky habitats extending deep into the water. There are over 130 fish species in this small area amongst the underwater cliffs, caves, crevicdes and bommies. Almost every bit of space on teh rocks is covered by marine plants and enrusting animals. Colourful sponges, corals and anemones can be seen in the deeper waters. Tropical fish species can be seen during the summer months.
NB: Check out this video of some snorkellers at Shiprock Aquatic Reserve.
To Log This EarthCache
To claim this EarthCache, please visit the listed coordinates and make careful observations of the Shiprock formation. You can walk around the platform by the water to get close up observations. Take care near the edge at all times as it can be very slippery. Answer the following questions:
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Regional Geology: What major rock type dominates Shiprock and much of the Sydney Basin, and how did it originally form?
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Formation Process: why do you think Shiprock “sticks out” more prominently into the estuary compared to surrounding cliff face?
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Observation: Looking closely at Shiprock. Describe at least one visible feature of the sandstone (e.g., colour variation, layering, cracks, erosion pattern, or surface texture).
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Photo: Post a photo of yourself or something with your geocaching name on it, along with the date of your visit, with SHIPROCK in the background, without revealing answers. See the examples below.
You may log your visit immediately to track your geocaching progress. However, to complete your EarthCache experience, please send your answers to the logging tasks via email or GC Messenger within 5 to 7 days. Failure to do so may result in your log getting deleted.
Important Notes on Preservation
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Shiprock is within a protected aquatic reserve. Please do not climb on, damage or remove rocks.
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Stay on designated paths and respect the environment.
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Leave the site exactly as you found it.
CONGRATULATIONS: FTF goes to Gatherer Hade
Resources:
https://www.abyss.com.au/blog/dive-sites/shiprock-aquatic-reserve
https://www.sutherlandshire.nsw.gov.au/play-and-explore/the-outdoors/parks-and-reserves/all-parks-reserves/shiprock-reserve-port-hacking
https://www.youtube.com/watch?v=1Gx6-OqGa2w
https://www.dpi.nsw.gov.au/fishing/marine-protected-areas/aquatic-reserves/shiprock-aquatic-reserve
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Did you know that NSW has a geocaching association? Geocaching NSW aims to enhance and improve the activity of geocaching and holds regular events where geocachers meet to enjoy their common interests. Visit the association website here. |