Cuddie Springs
Encyclopedia
Cuddie Springs is a notable archaeological
and paleontological
site in the semi-arid zone of central northern New South Wales
, Australia
(near Brewarrina). Cuddie Springs is an open site, with the fossil deposits preserved in a claypan
on the floor of an ancient ephemeral lake. The claypan fills with water after local rainstorms and often takes months to dry, a fact which facilitated the survival of fossils over a long period of time.
The site provided the first unequivocal association of stone artefacts with fossil remains of Australian megafauna
. Cuddie Springs has been known as a fossil megafauna locality since the late 1870s, when a well was sunk into the centre of the claypan. The Australian Museum
launched excavations in 1933 and while many bones were found, no significant discoveries were made in that initial research. More extensive excavations have been continuing since 1997 by a team from the University of Sydney
at Cuddie Springs suggests that climate changes that began before the human colonisation of Australia were responsible for the megafauna extinctions. Wroe and Field (2006) cite the staggered extinctions that have been occurring since at least 130,000 years ago and the fact that megafauna in Tasmania
do not occur after 46,000 years ago but people only arrived across a land bridge at 37,000 years ago. This staggered decline, mostly occurring in contexts independent of humans, is linked to environmental evidence for increasingly arid and erratic conditions since 400–300,000 years ago. The large body size of the megafauna suggests low fecundity
and low population densities which have been argued to have made them especially susceptible to extinction due to habitat loss from increasing aridity (Wroe and Field 2006).
The 10,000 years of co-habitation of humans and megafauna at Cuddie Springs that is the foundation of Wroe and Field’s argument has been the subject of intense critical examination. This critique has identified a number of details that weaken the integrity of the association between humans and megafauna. First are the finds themselves, such as relatively large number of grinding stone
s in Pleistocene
-age layers (Fullagar and Field 1997), as well as tula-adze-like flakes (David 2002). The Pleistocene grinding stones are notable because they imply a broad-spectrum plant-processing economy much earlier than previously known in Australia (Fullagar and Field 1997). These finds are anomalous because in other parts of Australia they are restricted to late Holocene
contexts (Gillespie and David 2001). Amongst the megafauna bone layers there is a tooth of a crocodile (Pallimnarchus
sp.) that became extinct long before 40,000 years ago (Gillespie and David 2001). The tooth is also exfoliated and heavily mineralised and the preservation is not consistent with other bone and teeth in the same level. There are stone artefacts with hair and blood adhering, but in the same layers there are megafauna bones with not even traces of protein remaining (Brook, et al. 2006; Coltrain, et al. 2004; Dodson, et al. 1993; Garling 1998).
These inconsistent finds suggest that the process of site formation may have involved some mixing of materials of different ages. This leads to the second important detail, the stratigraphy
. Cuddie Springs is unusual in having a dense deflation pavement that separates recent materials (such as cow bones) from the Pleistocene layers. The layers above the pavement contains cow bones mixed with megafauna bones but the layers below contain no cow bones. (Field and Dodson 1999). David (2002) has asked where the rocks in this pavement come from in a stone-poor riverine plain, and suggested that they may been carried by Aboriginal people from a gibber plain 4 km from the site or by farmers during the late 19th or early 20th century to create a firm footing for people or cattle. Gillespie and Brook (2006) also suggest that the stone artefacts in the pavement are unusually dense for a Pleistocene archaeological site
and may have been transported during well construction or represent an in situ but late Holocene archaeological site overlaying disturbed Late Pleistocene sediments. There is a long history of European activity at Cuddie Springs, with a well dug in 1876, ten metres from the 1990s excavation and trenches dug by the Australian Museum in 1933. These events likely caused disturbance of the stratigraphy. Gillespie and Brook add that cattle visiting the well may have pushed stone artefacts through the pavement into the Pleistocene layers during waterlogged conditions. Tracing the origins of the pavement is crucial to understanding the integrity of the Pleistocene layers.
Several authors have suggested that the Pleistocene stone artefacts and megafauna bones may have derived from separate contexts that have become mixed by underground water flow. Because it is a ground-fed spring and a site that is periodically inundated by rain, sediment at Cuddie Springs is highly likely to have been moved by water. The depth of the historic well suggests that the ground water level may have been near the level of the Pleistocene layers (Gillespie and Brook 2006). Gillespie and David (2001) suggest that the upright orientation of an unarticulated Genyornis
femur
in the Pleistocene layers at Cuddie Springs might be explained by sediment movement by water flow is responsible for. This suggests that the megafauna bones might derive from much older sediments and have been reworked into the stone artefact bearing layers. A more direct link between the stone artefacts and the bones would be cut marks on the bones, but there are ‘few cut marks on any bones’ at Cuddie Springs (Field, et al. 2001: 698). Evidence favour of an intact Pleistocene deposit comes from analysis of rare earth elements (REE) in the megafauna bones. The REE contents of the bones suggests that each depositional unit contains fauna with a discrete chemical signature and, therefore, a discrete and distinct postdepositional history, arguing against any postdepositional movement and mixing of bone between stratigraphic horizons (Trueman, et al. 2005). Gillespie and Brook (2006) comment that this still does not exclude an off-site origin of the bones (i.e. death of the animal) and subsequent fluvial transportation to Cuddie Springs. Field et al. (2006) dispute the proposal that flood movement caused the combination of megafauna and stone artefacts. They report that the sediments enclosing the bones and stones are fine-grained silts and clays resulting from a low-energy flow of water. They argue that if floods were responsible then larger sediments such as sands and gravels would have been found also.
The possibility of mixed Pleistocene deposits is also suggested by some interpretations of the chronology of the site, a third focus of the critiques (figure 6). So far, there are 20 radiocarbon dates and seven luminescence dates published for Cuddie Springs (Gillespie and Brook 2006). Statistical analysis by Gillespie and Brook (2006) of the 16 radiocarbon dates from the Pleistocene layers (ranging from 28 to 33,000 years ago) suggest that they do not increase in age as depth increases. They interpret this to mean that the sediments have been disturbed since they were first deposited. The luminescence dates also suggest mixing, with Roberts et al. (2001) finding that the sediments sampled for dating have multiple palaeodose populations, suggesting that sediments in the same sample were deposited at different times, rather than all at the same time. As mentioned above, the megafauna bones contain undetectable amounts of protein, so direct dating of the bones has so far been unsuccessful (Clarke 1999; Coltrain, et al. 2004).
The uniqueness of archaeological and palaeontological finds from Cuddie Springs and its unusual stratigraphy have attracted especially detailed critiques that cast doubt on the integrity of the human-megafauna coexistence. Despite these problems, Cuddie Springs is uniquely significant as a major focus of research into the question of how the Australian megafauna became extinct.
Archaeology
Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...
and paleontological
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
site in the semi-arid zone of central northern New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
(near Brewarrina). Cuddie Springs is an open site, with the fossil deposits preserved in a claypan
Claypan
In geology, a claypan is a dense, compact, slowly permeable layer in the subsoil having a much higher clay content than the overlying material, from which it is separated by a sharply defined boundary. Claypans are usually hard when dry, and plastic and sticky when wet. They limit or slow the...
on the floor of an ancient ephemeral lake. The claypan fills with water after local rainstorms and often takes months to dry, a fact which facilitated the survival of fossils over a long period of time.
The site provided the first unequivocal association of stone artefacts with fossil remains of Australian megafauna
Australian megafauna
Australian megafauna are a number of large animal species in Australia, often defined as species with body mass estimates of greater than 30 kilograms, or equal to or greater than 30% greater body mass than their closest living relatives...
. Cuddie Springs has been known as a fossil megafauna locality since the late 1870s, when a well was sunk into the centre of the claypan. The Australian Museum
Australian Museum
The Australian Museum is the oldest museum in Australia, with an international reputation in the fields of natural history and anthropology. It features collections of vertebrate and invertebrate zoology, as well as mineralogy, palaeontology, and anthropology...
launched excavations in 1933 and while many bones were found, no significant discoveries were made in that initial research. More extensive excavations have been continuing since 1997 by a team from the University of Sydney
University of Sydney
The University of Sydney is a public university located in Sydney, New South Wales. The main campus spreads across the suburbs of Camperdown and Darlington on the southwestern outskirts of the Sydney CBD. Founded in 1850, it is the oldest university in Australia and Oceania...
Evidence for human co-existence with Australian megafauna
The excavators of Cuddie Springs reject humans as the primary cause of megafauna extinctions. They conclude that the 10,000 years of co-habitation of humans and megafaunaMegafauna
In terrestrial zoology, megafauna are "giant", "very large" or "large" animals. The most common thresholds used are or...
at Cuddie Springs suggests that climate changes that began before the human colonisation of Australia were responsible for the megafauna extinctions. Wroe and Field (2006) cite the staggered extinctions that have been occurring since at least 130,000 years ago and the fact that megafauna in Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
do not occur after 46,000 years ago but people only arrived across a land bridge at 37,000 years ago. This staggered decline, mostly occurring in contexts independent of humans, is linked to environmental evidence for increasingly arid and erratic conditions since 400–300,000 years ago. The large body size of the megafauna suggests low fecundity
Fecundity
Fecundity, derived from the word fecund, generally refers to the ability to reproduce. In demography, fecundity is the potential reproductive capacity of an individual or population. In biology, the definition is more equivalent to fertility, or the actual reproductive rate of an organism or...
and low population densities which have been argued to have made them especially susceptible to extinction due to habitat loss from increasing aridity (Wroe and Field 2006).
The 10,000 years of co-habitation of humans and megafauna at Cuddie Springs that is the foundation of Wroe and Field’s argument has been the subject of intense critical examination. This critique has identified a number of details that weaken the integrity of the association between humans and megafauna. First are the finds themselves, such as relatively large number of grinding stone
Grinding Stone
Grinding Stone is a 1973 debut album by Gary Moore, released under the "The Gary Moore Band" moniker.-Track listing:All songs by Gary Moore.# "Grinding Stone" – 9:38# "Time to Heal" - 6:19# "Sail Across the Mountain" - 6:58...
s in Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
-age layers (Fullagar and Field 1997), as well as tula-adze-like flakes (David 2002). The Pleistocene grinding stones are notable because they imply a broad-spectrum plant-processing economy much earlier than previously known in Australia (Fullagar and Field 1997). These finds are anomalous because in other parts of Australia they are restricted to late Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
contexts (Gillespie and David 2001). Amongst the megafauna bone layers there is a tooth of a crocodile (Pallimnarchus
Pallimnarchus
Pallimnarchus is a genus extinct mekosuchine crocodylian from the Pliocene and Pleistocene of Australia. Remains of this animal have been found in the Riversleigh lagerstätte of northwestern Queensland. It was medium-sized, up to 5 meters long...
sp.) that became extinct long before 40,000 years ago (Gillespie and David 2001). The tooth is also exfoliated and heavily mineralised and the preservation is not consistent with other bone and teeth in the same level. There are stone artefacts with hair and blood adhering, but in the same layers there are megafauna bones with not even traces of protein remaining (Brook, et al. 2006; Coltrain, et al. 2004; Dodson, et al. 1993; Garling 1998).
These inconsistent finds suggest that the process of site formation may have involved some mixing of materials of different ages. This leads to the second important detail, the stratigraphy
Stratigraphy
Stratigraphy, a branch of geology, studies rock layers and layering . It is primarily used in the study of sedimentary and layered volcanic rocks....
. Cuddie Springs is unusual in having a dense deflation pavement that separates recent materials (such as cow bones) from the Pleistocene layers. The layers above the pavement contains cow bones mixed with megafauna bones but the layers below contain no cow bones. (Field and Dodson 1999). David (2002) has asked where the rocks in this pavement come from in a stone-poor riverine plain, and suggested that they may been carried by Aboriginal people from a gibber plain 4 km from the site or by farmers during the late 19th or early 20th century to create a firm footing for people or cattle. Gillespie and Brook (2006) also suggest that the stone artefacts in the pavement are unusually dense for a Pleistocene archaeological site
Archaeological site
An archaeological site is a place in which evidence of past activity is preserved , and which has been, or may be, investigated using the discipline of archaeology and represents a part of the archaeological record.Beyond this, the definition and geographical extent of a 'site' can vary widely,...
and may have been transported during well construction or represent an in situ but late Holocene archaeological site overlaying disturbed Late Pleistocene sediments. There is a long history of European activity at Cuddie Springs, with a well dug in 1876, ten metres from the 1990s excavation and trenches dug by the Australian Museum in 1933. These events likely caused disturbance of the stratigraphy. Gillespie and Brook add that cattle visiting the well may have pushed stone artefacts through the pavement into the Pleistocene layers during waterlogged conditions. Tracing the origins of the pavement is crucial to understanding the integrity of the Pleistocene layers.
Several authors have suggested that the Pleistocene stone artefacts and megafauna bones may have derived from separate contexts that have become mixed by underground water flow. Because it is a ground-fed spring and a site that is periodically inundated by rain, sediment at Cuddie Springs is highly likely to have been moved by water. The depth of the historic well suggests that the ground water level may have been near the level of the Pleistocene layers (Gillespie and Brook 2006). Gillespie and David (2001) suggest that the upright orientation of an unarticulated Genyornis
Genyornis
Genyornis was a monotypic genus of large, flightless bird that lived in Australia until 50±5 thousand years ago. Many species became extinct in Australia around that time, coinciding with the arrival of humans....
femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
in the Pleistocene layers at Cuddie Springs might be explained by sediment movement by water flow is responsible for. This suggests that the megafauna bones might derive from much older sediments and have been reworked into the stone artefact bearing layers. A more direct link between the stone artefacts and the bones would be cut marks on the bones, but there are ‘few cut marks on any bones’ at Cuddie Springs (Field, et al. 2001: 698). Evidence favour of an intact Pleistocene deposit comes from analysis of rare earth elements (REE) in the megafauna bones. The REE contents of the bones suggests that each depositional unit contains fauna with a discrete chemical signature and, therefore, a discrete and distinct postdepositional history, arguing against any postdepositional movement and mixing of bone between stratigraphic horizons (Trueman, et al. 2005). Gillespie and Brook (2006) comment that this still does not exclude an off-site origin of the bones (i.e. death of the animal) and subsequent fluvial transportation to Cuddie Springs. Field et al. (2006) dispute the proposal that flood movement caused the combination of megafauna and stone artefacts. They report that the sediments enclosing the bones and stones are fine-grained silts and clays resulting from a low-energy flow of water. They argue that if floods were responsible then larger sediments such as sands and gravels would have been found also.
The possibility of mixed Pleistocene deposits is also suggested by some interpretations of the chronology of the site, a third focus of the critiques (figure 6). So far, there are 20 radiocarbon dates and seven luminescence dates published for Cuddie Springs (Gillespie and Brook 2006). Statistical analysis by Gillespie and Brook (2006) of the 16 radiocarbon dates from the Pleistocene layers (ranging from 28 to 33,000 years ago) suggest that they do not increase in age as depth increases. They interpret this to mean that the sediments have been disturbed since they were first deposited. The luminescence dates also suggest mixing, with Roberts et al. (2001) finding that the sediments sampled for dating have multiple palaeodose populations, suggesting that sediments in the same sample were deposited at different times, rather than all at the same time. As mentioned above, the megafauna bones contain undetectable amounts of protein, so direct dating of the bones has so far been unsuccessful (Clarke 1999; Coltrain, et al. 2004).
The uniqueness of archaeological and palaeontological finds from Cuddie Springs and its unusual stratigraphy have attracted especially detailed critiques that cast doubt on the integrity of the human-megafauna coexistence. Despite these problems, Cuddie Springs is uniquely significant as a major focus of research into the question of how the Australian megafauna became extinct.