PALAEONTOLOGY
Java man not so old after all
erectus at Sangiran, ranging from 1.3 to
0.6 million years old.
To figure out whether the fossils were
older or younger, Shuji Matsu’ura from the
National Museum of Nature and Science
in Tsukuba City, Japan, and colleagues
used two separate dating techniques not
previously employed at the site.
Uranium-lead dating, which measures
the crystallisation age, and fission track
dating, which measures the volcano
eruption age, of zircon grains show that
volcanic ash just below the fossil-bearing
layers are only 1.3 million years old.
The younger age of first appearance at
Sangiran fits with other remains on Java that
have been dated to 1.49 million years old.
It also puts to bed ideas that the
birthplace of Homo erectus could have been
in Southeast Asia. It now seems much more
likely that Homo erectus arose in Africa
and dispersed out through Georgia in the
Caucasus, where the oldest Homo erectus
remains – aged 1.85 million years – have
been found. From there, they dispersed
into Asia. – DYANI LEWISStudying wasp
nests to put an
age on art
Rock paintings are younger than
suspected, scientists say.Scientists believe famous pre-historic
rock paintings in Western Australia’s
Kimberley region are younger than
previously thought after dating the
remnants of mud wasp nests found over
and beneath them.
The Gwion Gwion paintings have been
notoriously hard to date, but evidence has
suggested they were painted as far back
as 17,000 years ago and over the span of
several thousand years.
Now a team led by Damien Finch from
the University of Melbourne, with input
from the Australian Nuclear Science and
Technology Organisation, has presented
findings in the journal Scientific Advances
suggesting they were more likely painted
during a narrow timeframe about 12,
years ago.
Working with the traditional owners of
the sites, they analysed mud nests of wasps
built on rock walls, which sometimes
incorporated charcoal from regular local
brushfires.
By dating the charcoal in the nests,
they estimated when the nests were built.
By dating nests that had been painted
over, they determined the maximum age
of the artwork.
By dating nests on top of paintings,
they found minimum ages.- NICK CARNE
ARCHAEOLOGY
HISAO BABA/NATIONAL MUSEUM OF NATURE AND SCIENCE; MARK JONESFirst human species out of Africa
reached Asia later than thought.The oldest human remains in Southeast
Asia may not be as old as we thought they
were.
An Indonesian-Japanese team of
scientists has overturned a decades-old
estimate of Homo erectus remains from
Central Java province in Indonesia, shaving
off several hundred thousand years from
the age of the globe-trotting hominin, the
first to disperse out of Africa.
The new estimate, published in the
journal Science, puts Homo erectus at the
fossil-rich Sangiran dome by around
1.3 million years ago, and certainly no
earlier than 1.5 million years ago
That’s at least 300,000 years younger
than a long-standing estimate from the
1990s, which suggested the oldest Homo
erectus remains at Sangiran could be up to
1.8 million years old.
The age has remained controversial,
though, because some studies have come
up with much younger estimates for HomoDIGEST
10 – COSMOS Issue 86