Sip back as we discover Australia and explore the Gogo Formation exposed along the Lennard Shelf of the remote Canning Basin part of a once huge Late Devonian barrier reef complex on the northern margin of east Gondwana facing a warm Paleotethys Ocean in what is now the Kimberley of Western Australia. The Gogo Formation is an ancient reef platform rock and internationally a significant fossil location where an exceptionally preserved lagerstätte of soft tissue fossils from a biodiverse assemblage of invertebrates and vertebrate fauna exist dated from between the middle Givetian to early Frasnian Age’s of the Late Devonian Period some 384 – 382 million years ago.
The 430-meter thick Gogo Formation is made up of black fine-grained shales, siltstones and limestone that holds in its concretions fossils that have undergone the process of phosphatisation. This is where calcium-phosphate minerals have replaced decomposed soft tissues with apatite sitting alongside the other hard parts of teeth.
The marine fossils of the Gogo Formation helps to explain the origins of teeth, internal organ structures, bone, cartilage and provides insights into the fin-to-limb transition of early Gnathostomata or jawed vertebrates.
The Gogo Formation tells a story of pelagic or open water living Late Devonian reef faunas living in the sunlight zone of the water column that upon death sank to an oxygen depleted seabed to be fossilised in a calcium phosphate mud.
The Kimberley Region or simple, "The Kimberley" of Western Australia is one of the world’s most breath taking and remote travel destinations offering an unparalleled blend of rugged natural beauty, rich cultural heritage, and outdoor adventure. Spanning over 420,000 square kilometres this ancient landscape is home to dramatic gorges, pristine waterfalls, unique wildlife, and some of the world’s oldest Indigenous peoples and their rock art.
Among Kimberley’s stand out geodiversity is the Bungle Bungle Range in Purnululu National Park recognised as a UNESCO World Heritage Site. These striking orange-and-black striped sandstone domes are over 350 million years old and are best explored by foot or scenic helicopter flights.
The Karijini National Park and Australia's second largest National Park centred in the Hamersley Ranges of the Pilbara region in the north-western section of Western Australia. This is a vast area where the traditional owners of Banyjima, Innawonga and Kurrama people live.
Another must-see is the 1,000 tiny islands of the Buccaneer Archipelago where tidal currents create a natural phenomenon known as the horizontal waterfall best experienced by boat or seaplane.
The Kimberley is also renowned for its waterways, including the Ord River, Fitzroy River and Lake Argyle, offering opportunities for cruises, kayaking, and fishing. Visitors can marvel at the majestic Mitchell Falls or enjoy the cascading pools of Bell Gorge known as Dalmanyi a gorge in the Wunaamin Miliwundi Ranges Conservation Park whose traditional owners are the Ngarinyin people.
For those four-wheel drive (4WD) enthusiasts among you head for the Gibb River Road. Considered to be one of Australia's most scenic and adventurous outback drives. This 660Km route traverses the heart of the Kimberley.
Accessible from April to October after the wet season be prepared and plan ahead, changing road and weather conditions will be the norm and above all be aware of crocodiles. The Kimberley or Pilbara regions is also crocodile country home to both the estuarine or saltwater crocodile and the freshwater crocodile so be CrocWise.
Since the discovery of the Gogo fish fossils in the Gogo Formation in 1963 by British Museum palaeontologist Harry Toombs and where now these collections are housed at both the Natural History Museum in London and the Western Australia Museum.
The Gogo Fish Fossil Site has been described as ‘the world's most significant Devonian fish site’ with incredible diversity of species. Gogo fossils have helped to unlock knowledge about the evolutionary development of several fish groups including armoured fish, lungfish, early lobe-finned fish and early ray-finned fish.
The Gogo Formation was originally located during the Devonian Period on the edge of Gondwana in a subtropical zone facing a warm Paleotethys Ocean whose nutrient-rich environment fuelled the evolution of a wide variety of marine life. The Gogo Formation today is now part of a sequence of laminated sedimentary limestone rocks that flank the Kimberley Ranges for over 350Km.
The sediments of the Gogo Formation represent a deep and stable water environment with an oxygen depleted seafloor of a large tropical reef composed primarily of algae and stromatoporoids an ancient sponge reef builder. This was an environment where organisms were rapidly buried by sediments that helped to create extraordinarily well-preserved fossils of both invertebrates and vertebrates.
Invertebrate fossils (a) Montecaris gogoensis, (b) Dithyrocaris sp. (field shot), (c) ‘Mushia’ an undescribed arthropod, (d) undescribed eurypterid, (e) Concavicaris sp., (f) maxilla of Montecaris gogoensis GLAHM 109466, (g) conularid, (h) field shot of Gogo mollusc and (i) field shot of Gogo brachiopod. Specimens in a and c–e are held in the collections of Museum Victoria, Melbourne, specimen f is in the Hunterian Museum, Glasgow, and the specimen in g is held at the South Australian Museum.
The invertebrates of the Gogo Formation were mainly arthropods including the bivalved arthropods of phyllocarids, thylacocephalans and an unusual fossil called ‘Mushia’. Consisting of soft tissue, muscle and having visible body segmentation this organism is believed to have been some form of crustacean based upon chemotaxonomy. This is a technique that compares the chemical compounds in organisms to identify similarities and differences but ‘Mushia’ had no apparent head of other features resembling a crustacean. Curious?
The vertebrate fauna of the Gogo Formation is dominated by arthrodire placoderms an extinct class of armoured fish that were some of the earliest jawed vertebrates and relative to Dunkleosteus regarded as a super predator of the latest Devonian period growing up to 6 meters in length.
The Gogo Formation also contains many species of lungfish, ptyctodonts and early actinopterygians. Along with these were also onychodonts, coelacanths, chondrichthyans, acanthodians, Antiarch placoderms, Conodonts (an extinct group of jawless vertebrates), a stem marine tetrapodomorph called Gogonasus andrewsae and an early lobe-finned fish called Moythomasia considered to be a precursor to the ancestors of amphibians - the detailed anatomy of these organisms including their lobed pectoral fins are similar to the limbs of modern tetrapods (four-limbed animals).
The Gogo Formation fossils key to understanding the evolutionary transition from aquatic to terrestrial life. Interestingly, the abundance and diverse size range of the actinopterygians suggests that they were schooling fish.
Gogo fish preservation (a) antiarch Bothriolepis sp. (WAM 90.12.136); (b) actinopterygian Moythomasia durgaringa (South Australian Museum specimen, yet to be registered); (c) arthrodire Latocamurus coulthardi (WAM 86.9.699); (d) chirodipterid lungfish Chirodipterus australis showing body and head in lateral view (left, NHM P56035) and palatal dentition (right, WAM 90.10.8); (e) long-snouted lungfish Griphognathus whitei: juvenile head in lateral view (left, Western Australian Museum specimen) and palatal dentition (right, ANU 49219).
Its among the fossils discoveries of the arthrodire placoderms and ptyctodonts that the presence of fossilised embryo’s and a preserved umbilical cord have been found. These tissues indicate that internal fertilization and live birth occurred much earlier than was previously considered. The discovery of detailed fossilised muscle tissue from the jaws, neck and abdomen of arthrodire placoderm suggests that would catch and trap live prey.
Among the placoderms is a predatory 25-centimetre-long Gogo Fish (Mcnamaraspis kaprios). First discovered in the Gogo Formation in 1986 by Dr John Long its genus was named several years later in 1995 to honour Dr Ken McNamara the former curator of invertebrate palaeontology at the Western Australian Museum.
Mcnamaraspis kaprios was among the first fish to have jaws and teeth and its fossil remains of soft tissue has shown a complex heart by comparison to other primitive fish. It is believed that the evolution of the heart help it move faster. The Gogo Fish is today the fossil emblem for the State of Western Australia (Page 50) and also holds a Guinness World Record for having the earliest heart.
Western Australia and the Kimberley region is an extraordinary place to have an adventure especially if you are interested in understanding the regions geodiversity and fossil record dating back to the Devonian Period.