Our Geology & Soils
The NAR contains a diverse range of topography and soils, ranging from sandy beaches, gently undulating dunes and rocky promontories of the coastal areas to the inland semi-arid areas which are characterised by stony ridges, abrupt escarpments with broad valleys separated by stony, sediment plains with shallow soils. The region has a high level of cultural heritage as well as containing areas of significant natural beauty such as the coastline and offshore islands, the Moresby Ranges and a number of dissecting rivers and estuarine systems. Other key landscape elements include Mt Lesueur, Kalbarri gorges and the coastal areas of the NAR.
The NAR and Kalbarri in particular is home to many interesting fossil discoveries. The euthycarcinoid Kalbarria brimmelae discovered in the Tumbalgooda Sandstone of the Murchison River, was one of the first animals to live on land. Fossil tracks of a giant water scorpion called Eurypterid can be seen at Kalbarri National Park’s Ross Graham Lookout. In the early 90’s a new species of pliosaurid reptile was discovered in early cretaceous birdrong sandstone of the Carnarvon Basin, near Kalbari. The three partial skeletons of small pliosaurid plesiosaurs were found with two being described as Leptocleidus clemai sp. nov. The third is indeterminate. Read the full report. Dinosaur fossils have also been found around Geraldton and Dandaragan. The fossil remains of tibia (leg bone) uncovered from the Colalura Sandstone near Geraldton was from an Ozraptor subotai. The Ozraptor was a carnivore standing about three metres tall and was alive during the Jurassic period.
Data courtesy of the Department of Agriculture and Food WA. © State of Western Australia 2014.
Data courtesy of the Geological Survey of Western Australia, Department of Mines and Petroleum. © State of Western Australia 2013
Arramall Cave and Lake System
Arramall Cave is located just off the Brand Highway, around 30 km south of Dongara in ancient aeolian calcarenite limestone. Two major systems have been formed as a result of the overflow of Lake Arramall – River Cave and Arramall Cave, the latter of which contains the largest chambers and extends for approximately 1.8 km. Arramall caves flood infrequently when rains of sufficient volume to flood Lake Arramall are received. Details of the occurrence of selected fauna in Arramall and other caves in the surrounding area can be found on the Western Australian Speleological Group website.
Cattamarra Coal Measures
The Cattamarra Coal Measures was formed during the Jurassic period from volcanic and sedimentary rocks. The formation comprises of siltstone, shale, claystone, coal and sandstone.
Coalseam Conservation Park
A small reserve north of Mingenew that boasts a rich history (it is the site of the first coal mine in WA) and geology. The Park is surrounded by farmland and provides a sanctuary for wildlife, and is well known for its resident striated cliff faces, marine fossils and wildflowers.
A remnant of the western edge of the Victoria Plateau, the Morseby Range is a prominent landscape feature to the north and east of Geraldton, with high conservation value. The Range’s distinctive lateritic flat tops extend to around 200 m in height and run for about 33 km in length, roughly parallel to the coast and an average of 6 km inland. The geology is susceptible to erosion by the action of wind and water. See the Moresby Range Management Strategy and the Moresby Range Management Plan for more information.
Vegetation associated with the Northampton Block
The Northampton Black is a geological formation of the Perth Basin. The vegetation associated with the Northampton Block is rich and contains 3 Critically Endangered, 3 Endangered and 8 Vulnerable flora species, which are threatened by introduced animals and weeds along with inappropriate fire regimes, all of which require management to ensure conservation.
The Yarragadee formation was formed during the Jurassic period form volcanic and sedimentary rock. The Yarragadee formation consists of fine to coarse grained sandstone with thin interbeds of shale.
Named after the wreck of a Dutch East Indies trading ship, the Zuytdorp Cliffs originate just north of the Murchison River mouth at Kalbarri, and extend for approximately 150 km north to Steep Point. The Cliffs are part of the Tamala Limestone formation and are of heritage, cultural and geological significance.