The Loop Trail, Kalbarri NP (Top trail)

A Geological Treasure 

Kalbarri National Park provides one of Australia's best opportunities to observe ancient sedimentary environments, early evidence of life on land and the powerful effects of erosion operating across vast timescales. From fossil-bearing sandstone and meandering river gorges to dramatic sea cliffs and natural rock sculptures, the park preserves a geological record that spans hundreds of millions of years. 

Where Ancient Life First Left Its Footprints

The park’s spectacular cliffs, gorges and coastal formations are made of Tumblagooda Sandstone - a distinctive red and white banded sedimentary rock that was deposited during the Silurian Period, approximately 400-430 million years ago. 

The Tumblagooda Sandstone is one of Australia's most significant geological formations because it preserves evidence of some of the earliest life to venture onto land. Fossil trackways and burrows found within the sandstone record the movements of ancient arthropods, including eurypterids (sea scorpions), trilobite-like animals and worm-like organisms that once inhabited this ancient coastline. These trace fossils provide valuable insights into ecosystems that existed long before dinosaurs appeared. 

Carving the Murchison River Gorge

The park's most famous geological feature is the Murchison River Gorge, a spectacular canyon system extending for approximately 80 kilometres. 

The formation of the gorge itself is relatively recent in geological terms. Geoscience studies indicate that tectonic movements elevated the landscape, which then allowed the river to erode deeply into the sandstone plateau, creating the steep-sided gorge seen today. 

Trails such as The Loop, Nature's Window, Z Bend and Hawks Head provide outstanding views into the gorge and reveal the horizontal layers of Tumblagooda Sandstone. 

Coastal Cliffs and Ocean Erosion

The park's coastal section showcases a different chapter of Kalbarri's geological story. Along the Indian Ocean shoreline, cliffs rise more than 100 metres above the sea, where relentless wave action, wind erosion and weathering continually reshape the coastline. 

Features such as Natural Bridge, Island Rock, Mushroom Rock, Rainbow Valley and Shellhouse demonstrate the power of this coastal erosion. Fractures within the rock are gradually enlarged by waves and weathering until arches, sea stacks and isolated rock remnants form.