The Lancefield Swamp is a rich fossil deposit from the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

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 b ...

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, 33.6km south of Puckapunyal and had a population of at least 2,743 at the 2021 census. History The are ...

Victoria Victoria most commonly refers to: * Queen Victoria (1819–1901), Queen of the United Kingdom and Empress of India * Victoria (state), a state of Australia * Victoria, British Columbia, Canada, a provincial capital * Victoria, Seychelles, the capi ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

Description

The site consists of a

bone bed A bone bed is any Geology, geological stratum or deposition (geology), deposit that contains bones of whatever kind. Inevitably, such deposits are Sedimentary rock, sedimentary in nature. Not a formal term, it tends to be used more to describe esp ...

lying directly atop a layer of

fluvial A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...

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 zoology, megafauna (from Ancient Greek, Greek μέγας ''megas'' "large" and Neo-Latin ''fauna'' "animal life") are large animals. The precise definition of the term varies widely, though a common threshold is approximately , this lower en ...

species are represented, although the majority of bones are from the eastern grey kangaroo (''

Macropus giganteus The eastern grey kangaroo (''Macropus giganteus'': gigantic large-foot; also great grey kangaroo or forester kangaroo) is a marsupial found in the eastern third of Australia, with a population of several million. Although a large ''M. giganteus ...

'') or the extinct '' Macropus titan'', 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 (continent), Australia during the Pleistocene, Pleistocene Epoch. Most of these species became extinct during the latter half of the Pleistocene, as part of the broader global L ...

. 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- ...

, 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 Last Glacial Coldest Period, was the most recent time during the Last Glacial Period where ice sheets were at their greatest extent between 26,000 and 20,000 years ago. Ice sheets covered m ...

. 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 In medical terminology, disarticulation is the separation of two bones at their joint, either traumatically by way of injury or by a surgeon during arthroplasty or amputation. See also * Joint dislocation * Acrotomophilia * Apotemnophilia * Amputa ...

, 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 is a Latin phrase meaning 'in place' or 'on site', derived from ' ('in') and ' ( ablative of ''situs'', ). The term typically refers to the examination or occurrence of a process within its original context, without relocation. The term is use ...

. 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, C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic matter 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 (continent), Australia during the Pleistocene, Pleistocene Epoch. Most of these species became extinct during the latter half of the Pleistocene, as part of the broader global L ...

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

modern humans Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are great apes characterized by their hairlessness, bipedalism, and high intelligen ...

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