TECHNICAL COMMENTS
Roberts et al. (1) suggested an age date of
around 46.4 thousand calendar years ago (ka)
for extinction of at least six genera of Australian megafauna based on dated articulated
remains. Since the exploitation of animals by
people inherently involves the disarticulation
of faunal remains, this criterion excludes
most archaeological sites. The two best archaeological sites that provide evidence of
human/megafauna overlap and interaction
through the Late Pleistocene in the region are
thus either ignored [Nombe Rockshelter (2)]
or dismissed as disturbed (Cuddie Springs).
Cuddie Springs, dated to 36.4 ka in the
oldest human levels that also contain
megafaunal remains, has been rejected using
two assertions: (i) sediment mixing and (ii)
the redeposition of bones from older to
younger units. Neither assertion can be justified with the data available from the site. At
Cuddie Springs, megafauna and extant fauna
are present with stone artifacts in sequential
stratigraphic horizons that exhibit distinctly
different assemblage characteristics (3). In
the earliest archaeological level, some of the
megafaunal bones are in close anatomical
position (3). The human/megafauna overlap
is sealed at its upper and lower limits by
consolidated old land surfaces (3), precluding
movement of older or younger material into
that horizon after its formation. The argument
for disturbance made by Roberts et al. (1)
contradicts the archaeological, faunal, palynological, and geomorphological data compiled for the site (3– 6). In particular, pollen
data can be an indicator of disturbance, yet
the pollen record for Cuddie Springs shows
typical trends of increasing aridity leading up
to the Last Glacial Maximum (LGM), as
identified at other sites (3, 7).
Optically stimulated luminescence (OSL)
ages for Cuddie Springs show increasing age
with depth and are consistent with the established radiocarbon chronology. Even though
single-grain OSL analyses suggest a mixture
of younger grains with older ones, none of the
older grain ages approach the dates Roberts et
al. claimed for megafaunal demise across the
continent. There is thus no evidence of any
sediments older than the stated OSL ages for
the site. Although they asserted that bones
have been redeposited, Roberts et al. offered
no mechanism for the manner in which older
megafaunal bones could be fed into an accumulating younger deposit unaccompanied by
older sediments.
The stratigraphic integrity of a site cannot
be assessed by dating alone. Dating is only
one component of site analysis—all available
data must be considered in context, and Cuddie Springs is no exception.
Judith Field
Department of Archaeology
University of Sydney
Sydney, NSW 2006 Australia
E-mail: J.Field@chem.usyd.edu.au
Richard Fullagar
School of Geosciences
University of Wollongong
Wollongong, NSW 2522 Australia
References
1. R. G. Roberts et al., Science 292, 1888 (2001).
2. D. Gillieson, M. Mountain, Archaeol. Oceania 18, 53
(1983).
3. J. Field, J. Dodson, Proc. Prehist. Soc. 65, 275 (1999).
4. J. Dodson et al., Archaeol. Oceania 28, 94 (1993).
5. J. Field, J. Dodson, I. Prosser, Quat. Sci. Rev., in press.
6. J. Furby, thesis, University of New South Wales
(1995).
7. J. Dodson, R. V. S. Wright, Quat. Res. 32, 182 (1989).
5 July 2001; accepted 23 August 2001
Response: To minimize the risk of dating
deposits containing reworked megafaunal remains, we concentrated on sites with articulated bones (1). This approach does not necessarily exclude all archaeological sites from
consideration [e.g. (2, 3)]. Many animals also
died through causes other than human predation, and some of their remains would have
been preserved in primary deposition at nonarchaeological sites. But we found no articulated elements younger than about 46 ka in
our continent-wide survey, and Miller et al.
(4) found no Genyornis eggshells younger
than this in central or southeastern Australia.
Both studies included the Murray–Darling
Basin, where Cuddie Springs is situated, so
the claimed survival of megafauna to
35,000 –28,000 radiocarbon years ago [about
41 to 33 ka (5)] at this site (6) requires
scrutiny.
There is no direct evidence that humans
interacted with megafauna at Cuddie Springs.
The disarticulated remains do not show extensive predepositional fragmentation or evidence
of selection of the most important meat- and
marrow-bearing elements [compare to (2)], and
the cut marks on bone relate to an extant species
of kangaroo (6). But considerable evidence exists for postdepositional disturbance of the human/megafauna units (5, 6a, and 6b). Some
bones are oriented vertically, and many exhibit
signs of postdepositional crushing, attributed to
trampling (6). Field and Dodson also acknowledged that some megafaunal elements are probably intrusive (6), and the single-grain optical
ages indicate some intrusion of sediments after
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Archaeology and Australian
Megafauna
36 ka (1). The variable degree of bone mineralization (6) and extensive degradation of proteins in the skeletal remains (7, 8) also cast
doubt on the entire assemblage dating to only
41 to 33 ka. We interpret the megafaunal material in the human/megafauna units as a lag
deposit, sourced from older bone-bearing sediments. Such sediments underlie the lowest cultural levels, with a stratigraphic break in the
critical period between .76 and 41 ka (6). We
propose that the sediments deposited during this
period were mostly removed by wind or water,
while the bones were concentrated and incorporated in sediments deposited after 41 ka. The
optical dating signal in sediments is reset upon
exposure to sunlight, so optical ages greater
than 41 ka would be obtained only if the grains
had been incompletely bleached.
Pollen from the human/megafauna units
can reveal little about any climatic trends
leading up to the LGM (23 to 19 ka), because
these units were mostly deposited between 41
and 33 ka (6). The evidence for subsequent
disturbance provided by optical dating (1)
need not be reproduced in the pollen data,
because each unit may have been contaminated by pollen of similar composition. There is
a stratigraphic break of at least 9 ka with the
overlying deposits, which accumulated after
24 ka (6 ). These deposits could contain
pollen of LGM age, but the incoherent
pattern of 14C ages and the presence of
glass flakes and modern cow bone above
the contact with unit 5 (6 ) indicate that the
pollen record is insensitive to substantial
postdepositional disturbance.
Reliable ages for the disarticulated remains at Cuddie Springs and Nombe Rockshelter can be determined only by direct dating, such as that used at Lancefield Swamp to
revise the age of the disarticulated assemblage from 31 ka to about 50 ka (8, 9).
Richard G. Roberts
Hiroyuki Yoshida
School of Geosciences
University of Wollongong
Wollongong, New South Wales 2522,
Australia
E-mail: rgrob@uow.edu.au
Timothy F. Flannery
South Australian Museum
Adelaide, South Australia 5000, Australia
Linda K. Ayliffe
Department of Geology and Geophysics
University of Utah
Salt Lake City, UT 84112, USA
www.sciencemag.org SCIENCE VOL 294 5 OCTOBER 2001
Jon M. Olley
CSIRO Land and Water
Canberra, ACT 2601, Australia
Gavin J. Prideaux
Department of Earth Sciences
University of California
Riverside, CA 92521, USA
7a
TECHNICAL COMMENTS
Geoff M. Laslett
CSIRO Mathematical and
Information Sciences
Melbourne, Victoria 3168, Australia
Alexander Baynes
Western Australian Museum
Perth, Western Australia 6000, Australia
M. A. Smith
National Museum of Australia
Canberra, ACT 2601, Australia
Barton L. Smith
Department of Earth Sciences
La Trobe University
Melbourne, Victoria 3086, Australia
3.
4.
5.
6.
7.
8.
9.
Hunting in Prehistoric New Zealand (Cambridge Univ.
Press, Cambridge, 1989).
D. J. Stanford, J. S. Day, Eds., Ice Age Hunters of the
Rockies (Denver Museum of Natural History/University Press of Colorado, Denver, CO, 1992).
G. H. Miller et al., Science 283, 205 (1999).
J. W. Beck et al., Science 292, 2453 (2001).
J. Field, J. Dodson, Proc. Prehist. Soc. 65, 275 (1999).
S. J. Clarke, thesis, University of Wollongong, New
South Wales (1999).
R. Gillespie, Radiocarbon, in press.
S. Van Huet, R. Grün, C. V. Murray-Wallace, N. Redvers-Newton, J. P. White, Aust. Archaeol. 46, 5
(1998).
References
1. R. G. Roberts et al., Science 292, 1888 (2001).
2. A. J. Anderson, Prodigious Birds: Moas and Moa-
23 July 2001; accepted 23 August 2001
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Rhys Jones
Department of Archaeology and
Natural History
Research School of Pacific and
Asian Studies
Australian National University
Canberra, ACT 0200, Australia
7a
5 OCTOBER 2001 VOL 294 SCIENCE www.sciencemag.org
Archaeology and Australian Megafauna
Judith Field and Richard Fullagar (October 5, 2001)
Science 294 (5540), 7. [doi: 10.1126/science.294.5540.7a]
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