The Lancefield Swamp is a rich fossil deposit from the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

was discovered in the 19th century near

Lancefield Lancefield is a town in the Shire of Macedon Ranges local government area in Victoria, Australia north of the state capital, Melbourne and had a population of 2,743 at the 2021 census. History The area was used by the indigenous aborigin ...

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Description

The site consists of a bone bed lying directly atop a layer of

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

gravel between layers of clay.Gillespie R. et al. "Lancefield Swamp and the Extinction of the Australian Megafauna", ''Science'' 200, 1978, 1044-8. The layer of bones is estimated to contain the remains of perhaps 10,000 individual Pleistocene animals. A total of at least six

megafauna In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common threshold ...

species are represented, although the majority of bones are from the eastern grey kangaroo ('' Macropus giganteus'') or the extinct ''

Macropus titan ''Macropus titan'' is an extinct species of kangaroo (a marsupial) that lived during the Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11, ...

'', which was closely related to the eastern grey. Human artefacts were found in the bone bed and in the overlying clay, but evidence of reworking by water flow has been noted. Thus it appears possible such artefacts are intrusions. The Lancefield Swamp fossil site is important in the debate over the time of and causes of the extinction of

Australian megafauna The term Australian megafauna refers to the megafauna in Australia during the Pleistocene Epoch. Most of these species became extinct during the latter half of the Pleistocene, and the roles of human and climatic factors in their extinction are ...

. Humans are estimated to have arrived in

, or prehistoric

Sahul __NOTOC__ Sahul (), also called Sahul-land, Meganesia, Papualand and Greater Australia, was a paleocontinent that encompassed the modern-day landmasses of mainland Australia, Tasmania, New Guinea, and the Aru Islands. Sahul was in the south-we ...

, at anything from 60 ka to about 45ka. Initial radiocarbon dates yielded estimates of 31ka, a comparatively young age, approaching the

Last Glacial Maximum The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Ice sheets covered much of Northern North America, Northern Eur ...

. Horton therefore claimed that Lancefield is a decisive example of the survival of Australian Megafauna for many thousands of years after the arrival of modern humans in prehistoric Sahul. However, when Lancefield Swamp was investigated by van Huet, it was found that the bones had been reworked by fast-flowing water at some time after the animals had died. That conclusion was based upon observations that the bones show signs of post-depositional wear, that they are all disarticulated, that complete skulls are lacking, that the majority of bones are large, and that they tend to be aligned along a common axis, indicative of the direction of water flow. Therefore, it appeared probable that lighter bones had been washed away whereas heavier bones remained in situ. Dating of

Diprotodon ''Diprotodon'' (Ancient Greek: "two protruding front teeth") is an extinct genus of marsupial from the Pleistocene of Australia, containing one species, ''D. optatum''. The earliest finds date to 1.77 million to 780,000 years ago, but most speci ...

teeth from the bone bed yielded ages of 46-56ka by means of ESR, and a minimum of 32ka by means of

Carbon-14 Carbon-14, C-14, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and coll ...

dating. However, excavations begun in 2004 by Dortch et al. suggest that the Lancefield megafauna remains have not been disturbed since deposition.Dortch 2004:Formal Report
/ref> Therefore, is it is hoped that dates assigned to the Lancefield bones are reliable and therefore represent their true age since burial. If age estimates turn out to be on the high side, say 60ka or greater, the Lancefield bones may contribute less to our understanding of the effects of human activities upon the

Australian Megafauna The term Australian megafauna refers to the megafauna in Australia during the Pleistocene Epoch. Most of these species became extinct during the latter half of the Pleistocene, and the roles of human and climatic factors in their extinction are ...

, since such an age may pre-date the arrival of

modern humans Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, an ...

in Sahul. On the other hand, if the dates are comparatively recent, say less than 35ka, then humans would be exculpated as a causative agent of the decline of megafauna. However, if the estimate falls somewhere close to 46ka, then human arrival, and the final demise of the megafauna, could be associated.

References

{{reflist The Huet excavations were in a different part of the site to the original excavations. Also, Gillespie et al. did not find evidence of reworking, just the reverse. The deposits were clearly in situ in their part of the site.

External links

Dortch 2004:Lancefield Megafauna ExcavationMonash University PalaeontologyMonash Science Centre
Pleistocene paleontological sites of Australia

Description

See also

References

External links