Discover Tasmania and Explore the Geodiversity of Eaglehawk Neck
- Wayne Munday
- 7 minutes ago
- 3 min read
Sip back and discover Tasmania and explore the geodiversity of stunning Eaglehawk Neck, featured in the Netflix series, The Survivors. Discover the role played by the coastal cliffs and iconic dolerite formations dating back to the Jurassic Period as an imposing backdrop to this slow-burning murder mystery. Based on Jane Harper’s bestselling novel this whodunit story follows Kieran Elliott (Charlie Vickers) and his partner Mia Chang (Yerin Ha) as they return to Kieran’s hometown where a tragic drowning and a girl’s disappearance from his youth still haunt him. When a young woman’s body washes up on the beach, the past resurfaces, and secrets begin to unravel, threatening the stability of the fictional Evelyn Bay community. As well as a strong cast the series was also filmed along the narrow isthmus connecting the Tasman Peninsula to the Forestier Peninsula in southeastern Tasmania and within The Tasman National Park and the Pirates Bay Coastal Reserve. Roughly a hours drive via Arthur Hwy/A9 and Tasman Hwy/A3 from Hobart this a place known as one of Tasmania's most iconic coastal locations.
Eaglehawk Neck lies within the Tasman Structural Zone a part of the Tasman Fold Belt System which extends through much of eastern Australia. This region’s geology is complex and defined by a combination of sedimentary, igneous and tectonic processes
The dominant rock type in the Eaglehawk Neck region is Dolerite described as a dark, medium-grained mafic intrusive igneous rock formed when magma cools relatively quickly beneath the Earth’s surface typically in dykes and sills. The presence of Dolerite is associated with tectonically active regions.
The Dolerite at Eaglehawk Neck is part of the widespread Jurassic dolerite province formed approximately 182 million years ago. These dolerite intrusions are part of the vast Karoo -Ferrar Large Igneous Province (FLIP) a magmatic region that once spanned much of the ancient supercontinent Gondwana linking Tasmania with parts of Antarctica and southern Africa.
This province is dominated by widespread sills of horizontal magma sheets between rock layers and dykes of vertical magma intrusions into pre-existing sedimentary siltstone, mudstone and sandstone laid down during the Permian–Triassic transition as part of the Upper Parmeener Supergroup a prominent sequence in Tasmania.
The Upper Parmeener Supergroup in Tasmania tells a story environmental transformation during the Late Paleozoic Ice Age from cold glacial and marine conditions to a warmer continental and vegetated freshwater lowland characterised by rivers, lakes and swamps depositing sandstones, mudstones and forming coal.
Between 183 – 165 million years ago with peak activity around 175 million years ago during the Middle Jurassic was the break-up of Gondwana. It was a time of extensive igneous intrusion and the appearance of Dolerite long with sills, dikes and columnar outcrops. As this mafic intrusive igneous rock with jointed and columnar structure became exposed to coastal erosion it formed vertical cliffs, blow holes, sea stacks and other erosional sea cave landforms with now the local names like the Blowhole, Tasman Arch and Devil’s Kitchen.
The Tessellated Pavement
One of the most famous geological features near Eaglehawk Neck is the Tessellated Pavement a dramatic checkerboard like rock platform at the northern end of Pirates Bay. Though it initially appears to be man-made this natural formation is composed of Permian Period siltstone that has fractured into a distinctive pattern of polygonal "tiles".
These shapes result from orthogonal jointing a natural process where the rock has fractured along perpendicular lines due to contraction and stress. Over time, weathering and coastal erosion have deepened and refined these joints creating two distinct surface textures. Firstly, the Pan Formations where the block edges are raised by salt crystallization in the cracks and secondly, Loaf Formations where the block centres are raised by tidal erosion of the edges.
The geodiversity of Eaglehawk Neck is visually striking with its imposing dolerite cliffs and iconic tessellated pavements. What a great location to choose where the backdrop of local geology has not only captured a sense of unease and suspense but also supports in shaping the narrative, tone and emotion of this story.