GEOLOGY & PALEONTOLOGY COLLECTIONS

The Museums Victoria geology and palaeontology collections are of scientific and historic significance and date to the foundation of the National Museum of Victoria in 1854.

Pictured here is a fossil claw of a Theropod, part of the Museums Victoria Vertebrate Palaeontology Collection. It was the first dinosaur bone found in Victoria and is commonly known as “the Cape Paterson Claw”.

Curation notes by: Lucinda Horrocks, Wind & Sky Productions and Museums Victoria.

THE PAST IS THE KEY TO THE FUTURE

What might the world look like in centuries to come as the Earth grows warmer?

One way to assess that is to examine the history of the planet for similar episodes.

Looking back over millions of years we can study periods when the Earth was quite different, when the continents and oceans were in different configurations and the climate was significantly warmer or cooler.

The late Early Cretaceous, roughly 125 to 105 million years ago, was a greenhouse world. Back then the atmosphere was humid and high in carbon dioxide, the oceans were warm and there was little or no continental ice. Oddly enough, though the climate then was much warmer than it is today, Victoria was one of the coldest places on the planet because it was close to the South Pole.

So what the situation here was like then is a guide for the future — not in Australia, but the current polar regions of the Northern Hemisphere.

This image is a visualisation of a summer’s day by a river bank for a group of dinosaurs 125 million years ago.

On a summer’s day in polar Australia the sun would shine nearly all day. As with polar regions today, the Cretaceous South Pole would be warmer in summer than during the long and gloomy winter.

The average annual temperature of the South Pole in that deep past was probably somewhere between freezing and 10 degrees Celsius.

Curation notes by: Thomas Rich, Curator of Vertebrate Palaeontology Museums Victoria and Stephen Poropat, Swinburne University with Kate Phillips, Senior Curator Science, Museums Victoria and Lucinda Horrocks, Wind & Sky Productions.

In this visual reconstruction of a winter’s day in Victoria 125 million years ago, a tiny mammal (Bishops whitmorei) watches a group of ornithopod dinosaurs foraging for food in the snow.

At this time polar Australia fell into total darkness for at least six straight weeks during winter.

This visual restoration of what Victoria was like 125 million years ago is based on fossils held in the Museums Victoria collection.

Fossils of the animal, plant and insect life of the period give a picture of the region and habitat of life at the time and show species adapted to cold conditions.

Geological investigations set the scene in a rift valley between Australia and Antarctica.

Curation notes by: Thomas Rich, Curator of Vertebrate Palaeontology Museums Victoria and Stephen Poropat, Swinburne University with Lucinda Horrocks, Wind & Sky Productions.

This fossil of the mammal Bishops whitmorei was the basis of the pictorial representation of the little mouse-like creature depicted in Victoria’s polar past shown earlier.

Its fossilised jaw bone was found at Flat Rocks near Inverloch in Victoria. The animal is not known to have existed outside of Victoria.

This tiny animal lived in the Early Cretaceous period about 125 million years ago.

The fossil is part of the Museums Victoria Vertebrate Paleontology collection.

Curation notes by: Thomas Rich, Curator of Vertebrate Palaeontology Museums Victoria and Stephen Poropat, Swinburne University with Lucinda Horrocks, Wind & Sky Productions.

This well-preserved brain cast is a fossil of a species called Leaellynasaura amicagraphica which lived in Victoria 105 million years ago.

Leaellynasaura was a member of the ornithopod family - most were small dinosaurs barely larger than a chicken. Several ornithopod fossils have been found in Victoria suggesting they were common in Australia.

The Leaellynasaura skull bone is unusually large for a dinosaur of this family and it bears marks of large optic lobes which indicates it had particularly big eyes. One possible explanation is that this enabled better night vision, an adaptation that helped Leaellynasaura forage for food in Victoria’s long dark winter months 105 million years ago.

The fossilised skull was found at Dinosaur Cove in the Otways, Victoria, and is part of the Museums Victoria Vertebrate Paleontology collection.

Curation notes by: Thomas Rich, Curator of Vertebrate Palaeontology Museums Victoria and Stephen Poropat, Swinburne University with Lucinda Horrocks, Wind & Sky Productions.

ANCIENT CLIMATE CHANGE & MASS EXTINCTIONS OF CORALS & REEFS

If geologists could choose a ‘canary in the coal mine’ for dramatic climate change, corals, and reefs in general, would be it.

This has been true throughout the past half a billion years of geological history, basically since animals evolved, during which time the world has experienced significant fluctuations in climate.

Over hundreds of millions of years many animals have built reefs, from sponges to corals to bryozoans to bivalves and back to corals. But just as today’s coral reefs are sickening from the impacts of human-induced climate change, the ancient ocean reefs of the Earth’s deep past suffered when their environment changed. This is because reef-forming animal groups are sessile, which means they grow fixed in one spot on the sea floor. So a catastrophic collapse of the base of the food chain or a change in environment that they can’t escape (such as loss of oxygen) will hit these reef builders the hardest.

The coral species pictured here lived four hundred million years ago. It belonged to the taxonomic order Rugosa. Rugose coral species were either solitary, like this one, or colonial.

The fossil specimen was found in Lilydale in Victoria. It is part of the Museums Victoria Invertebrate Palaeontology Collection.

Curation notes by: Dr Rolf Schmidt, Collection Manager Invertebrate Palaeontology, Museums Victoria, and Lucinda Horrocks, Wind & Sky Productions.

For half a billion years there have been animal reefs in the world’s oceans.

Over this vast time period different animal groups have been reef-builders. Today we have coral reefs.

Individual coral animals are usually small, but they can form vast colonies by producing hundreds of clones linked together in one large skeleton. Each individual is completely soft-bodied, but they form a hard skeleton ‘house’ which glues onto rock or dead coral skeletons to form large underwater rock like structures - reefs.

This coral species lived 400 million years ago. It belonged to the taxonomic order Tabulata, which along with the Rugosa (described in the previous image) was one of two major coral groups that formed reefs in the Palaeozoic Era of 540 million to 250 million years ago.

Although these ancient corals superficially looked like modern corals, they are actually quite unrelated, apart from all belonging to the larger grouping of the Cnidaria (which also include sea jellies). The Cnidaria, which includes all types of corals as well as sea jellies, branched away from all other animals very early in their evolutionary history, and their bodies have radial symmetry, as opposed to the bilateral symmetry of all other animals.

They also uniquely have explosive cells that shoot venomous darts into their prey called nematocytes.

This fossil is part of the Museums Victoria Invertebrate Palaeontology Collection.

Curation notes by: Dr Rolf Schmidt, Collection Manager Invertebrate Palaeontology, Museums Victoria, and Lucinda Horrocks, Wind & Sky Productions.

252 million years ago the biggest mass extinction of all time wiped out all of the reef-forming coral groups.

The mass extinction is known as the Permian-Triassic extinction event, or the Great Dying, and is thought to have been triggered by widespread environmental change including climate change.

Pictured here is a fossilised coral Stephanocyathus tatei, which lived 22 million years ago when sea levels were much higher than today.

It belongs to the modern Scleractinian or stony corals, which first evolved about 250 million years ago soon after the Permian-Triassic Extinction event. Scleractinian corals are the dominant reef builders today.

The fossil pictured here is one of the solitary forms of Scleractinian coral. Unlike most corals today, it did not join with other animals in a colony, instead it grew into a single animal, likely adapted to living on soft sea floor sediments, 22 million years ago.

The specimen was found in Spring Creek near Torquay in Victoria. It is part of the Museums Victoria Invertebrate Palaeontology Collection.

Curation notes by: Dr Rolf Schmidt, Collection Manager Invertebrate Palaeontology, Museums Victoria, and Lucinda Horrocks, Wind & Sky Productions.

Not only are reef-building animals the most likely to become extinct after rapid environmental change, there are even “reef gaps” in the geologic record following mass extinctions, where no animal-based reefs formed for millions of years.

The only organisms to benefit during these times are single-celled, photosynthetic bacteria, which re-emerge during these gaps and form their own ‘reefs’ of layered rocky structures called stromatolites. Various forms of stromatolitic structures have formed for over 3 billion years when layers of photosynthesising bacteria growing on the sea floor alternate with fine sediment that settled on them, to eventually grow structures that could be meters thick and kilometres wide. Over the past 500 million years such stromatolites only occurred when and where there are no animals present to graze on them; such as today in the locally hostile conditions in Shark Bay Western Australia, or globally after major mass extinctions wiped out most grazing marine animals.

A re-emergence of bacterial growth within previously thriving coral reefs today may be an indicator of the stress and decline these ecosystems are experiencing right now.

Pictured are the stromatolites of Hamelin Pool Marine Nature Reserve in Shark Bay, WA, one of the few places in the world where living marine stromatolites can be found. Hamelin Pool is hypersaline, having approximately double the salinity of normal seawater. It is so salty that it inhibits marine life that would otherwise eat the bacteria which is forming the stromatolites.

Curation notes by: Dr Rolf Schmidt, Collection Manager Invertebrate Palaeontology, Museums Victoria, and Lucinda Horrocks, Wind & Sky Productions.

In today’s tropical waters we see coral bleaching which is associated with climate change.

Coral bleaching occurs when corals expel microscopic algae-like organisms called zooxanthellae which live inside the coral and give the coral reefs their colour.

Corals have evolved a symbiotic relationship with their zooxanthellae. Zooxanthellae convert the sun’s energy into nutrients the coral absorbs, a bonus in nutrient-poor tropical waters, and the coral host provides nutrients and access to sunlight to the organism in return.

Corals will expel the tiny organisms if they experience environmental stress such as high water temperature, cyclones, and pollution. This helps the corals survive in the short term as they no longer have to feed the zooxanthellae. However, this puts the corals on a course to starvation as zooxanthellae provide corals with crucial nutrients. Corals can recover and absorb new zooxanthellae if conditions become right again but their chances of survival are low if the poor environmental conditions persist.

Coral bleaching is triggered by environmental changes such as warming water associated with climate change.

Curation notes by: Dr Rolf Schmidt, Collection Manager Invertebrate Palaeontology, Museums Victoria, and Lucinda Horrocks, Wind & Sky Productions.

MÖSSBAUERITE: NATURAL WATER PURIFIER

Reducing the amount of nitrate in global waters could significantly help prevent algal blooms.

Recently Dr Stuart Mills, Senior Curator, Geosciences, Museum Victoria, along with Prof Jean-Marie Génin (University of Lorraine), Dr Andrew Christy (University of Queensland) and Dr. Odile Guérin (Sorbonne) discovered a mineral, mössbauerite, which could be a natural solution to purifying water that is affected by excess nitrate.

Nitrate pollution is caused by fertilizer runoff and is a major global problem responsible for algal blooms, which are a serious contaminant of many of the world’s water resources, including the Murray-Darling Basin.

Algal blooms are predicted to get more severe as climate change progresses. The increasing effects of climate change such as warmer water temperatures, increased freshwater salinity due to drought, sea level rises, higher atmospheric carbon dioxide levels and increased nutrient runoff from intense flooding are predicted to create conditions perfect for the growth of algae and lead to more algal blooms.

Pictured here is an aerial view of Reindeer Island, Lake Winnipeg, Canada, taken by the European Space Agency in 2017. The swirling shades of green in the water indicates a toxic algal bloom.

Curation notes by: Stuart Mills, Senior Curator Geology Museums Victoria with Lucinda Horrocks, Wind & Sky Productions.

Mössbauerite was discovered on the famous Mont Saint-Michel coastline of Normandy, France. It belongs to a group of compounds known as ‘green rust’.

Mixed with other green rust minerals mössbauerite forms a layer of greenish clay under the sand of the bay where it is unknowingly walked on by the 3.5 million tourists who visit the UNESCO world heritage site every year.

It has also been discovered on l'Île d'Aval, one of the localities where King Arthur is thought to be buried.

Mössbauerite and the green rust minerals play an important role in the natural purification of waters by converting nitrate from the water into harmless nitrogen gas, which is released into the atmosphere.

Curation notes by: Stuart Mills, Senior Curator Geology Museums Victoria.

Types of green rust also naturally occur in Australia.

Pictured here is Yanga Lake in New South Wales. Yanga Lake is the first locality in the world where pure, natural mössbauerite has been found, and the first locality where mössbauerite has been found in an inland setting.

Green rusts are already being used to naturally remove algae from major problem areas in Brittany and plans are in place for using synthetic versions of the mineral in water plants in France.

Ongoing research into the properties of green rusts such as mössbauerite have the potential to shape the way we treat and consume water into the future.

Curation notes by: Stuart Mills, Senior Curator Geology Museums Victoria.

Samples of mössbauerite have been collected by Dr Mills and now are part of the Museums Victoria Mineralogy Collection.

Because mössbauerite is a new scientific discovery the sample has been classified as a holotype specimen - the single physical example from which the mineral is defined. Holotypes are important reference items for scientific analysis and museums play a crucial role in collecting, storing and cataloguing type specimens.

Mössbauerite is named after Professor Rudolf Ludwig Mössbauer (1928–2011) who won the 1961 Nobel Physics Prize.

Curation notes by: Stuart Mills, Senior Curator Geology Museums Victoria with Lucinda Horrocks, Wind & Sky Productions.