Scuba diving to the depths of human history
Jack Linthicum
a ship off Cape Geledoniya in Turkey. The equipment and the methods
have improved and now there are serious looks at the area where the
sea is now but used to be dry land. The area between the present
shoreline and 50 to 150 meters down is where people lived prior to the
rise of the sea, 4000 years more or less. I, for one, would like to
learn more about the shipyard from 8000 years ago.
Scuba diving to the depths of human history
* 19 November 2009 by Dan Jones
Searching the seas. Artifacts found underwater are often better
preserved than relics found on land (Image: Jon Henderson/University
of Nottingham)
1 more image
KITTED out with the latest scuba gear, Garry Momber peers through the
murky water to the seabed below. It's dark - Momber is 11 metres below
the water's surface and the black peat of the seabed absorbs what
little light reaches the bottom. Then the tide turns, and as clearer
water flows in from the open seas, the decaying remains of an ancient
forest emerge from the gloom. Working quickly, he records details of
the exposed material before the strengthening current forces him away
from the site.
This is all in a day's work for Momber, who is director of the
Hampshire and Wight Trust for Maritime Archaeology in Southampton, UK.
His job is to search for clues to a prehistoric world lost beneath the
waves in the channel that separates the Isle of Wight from the south
coast of England - to be precise, at a location 300 metres off the
port of Yarmouth.
Momber's work is just part of a growing trend for searching the deep
for clues to our distant past. The field of underwater archaeology is
perhaps best known for unearthing relics from more recent history,
like Henry VIII's ship the Mary Rose, yet the seabed is stuffed with
clues to prehistory too - especially a murky period 11,500 years ago,
at the end of the last ice age, when early Europeans were slowly
changing from being nomadic hunter-gatherers into settled farmers.
Back then, sea levels were 50 metres lower than today, and the vast
majority of early societies would have lived on fertile land by the
coast. But as the ice sheets melted, millions of square kilometres of
coastal territory would have been flooded. By 4000 BC, when the
coastline had stabilised to roughly its current form, 40 per cent of
prehistoric Europe was submerged - along with much of the evidence for
their way of life.
"Anybody who was doing anything on the shore more than 6000 years ago
was doing it below present sea levels," says Nic Flemming of the UK's
National Oceanography Centre in Southampton.
The result is that remains found on land today are not going to tell
you much about these early societies. "If you leave out 40 per cent of
the data, you're going to make some serious mistakes," says Flemming.
What's more, finds from the sea floor are well preserved. Indeed they
are often in better condition than similar discoveries on land, since
the low-oxygen conditions in mud and peat sediments slow the decay of
organic material. Underwater sites can therefore provide unparalleled
insights into the lifestyles of our ancestors as the ice age ended.
"Underwater archaeology can open the door to how societies evolved and
developed," says Momber.
Underwater goes mainstream
Despite the treasures on offer, however, widespread acceptance of
prehistoric underwater archaeology has been a long time coming. Until
recently, underwater digs were regarded as dangerous and expensive,
with the evidence hard to find. "With that attitude, people just
didn't look under water," says Flemming, a pioneer of marine
archaeology.
Now the tide is turning. Chance finds made by recreational divers and
fishermen have whetted the appetite, and systematic investigations
around the Baltic, together with improved underwater imaging
techniques, have identified the best sites to look for human remains
(see "Rebuilding the prehistoric world"). The final turning point came
in 2003, when a multinational conference on the prehistoric potential
of the North Sea and an accompanying book highlighted the new
possibilities. "This really lit the blue touchpaper," says Flemming.
"It has taken some time for the scientific community to acknowledge
how important this is - and is going to be," says Jonathan Benjamin of
the University of Edinburgh, UK, "but underwater research is just now
becoming accepted in the mainstream of prehistoric archaeology."
Jeffrey Rose, an archaeologist at Oxford Brookes University, UK,
agrees: "This is the next big story in archaeology."
According to mainland archaeology, tribes living at the beginning of
the Mesolithic period were mobile hunter-gatherers, preying on deer
and wild boar in the continental heartland of Europe. Over the
following millennia, they began to concentrate on the newly formed
coastlines of northern Europe, becoming dedicated fishermen in the
process. Understanding this transition, and how people adapted to
coastal life, is tricky because rising sea levels had submerged these
coastal Mesolithic sites. "We've been missing virtually all of the
relevant evidence," says archaeologist Geoff Bailey of the University
of York, UK.
So where to look? The Baltic Sea seemed a good bet. Its brackish
waters are particularly low in oxygen, while bays created by the
convoluted coastline proved to be perfect havens for archaeological
material for thousands of years.
One of the first important discoveries was made back in the 1970s,
when Danish researchers unearthed a spectacular prehistoric site named
Tybrind Vig, 300 metres from the current Danish coastline. Inhabited
between 7500 and 6000 years ago, Tybrind Vig yielded three exquisitely
preserved canoes made from hollowed-out lime trees, up to 9 metres
long and each equipped with a stone fireplace, as well as paddles,
fish hooks and fish traps.
It looked as though at least some of the Baltic Mesolithic tribes were
intimately acquainted with the sea, but whether that was
representative of Mesolithic life further afield remained unclear,
until recent systematic excavations.
For example, the Sinking Coasts project, or SINCOS, has been
undertaking rigorous excavations along the German coast for the past
seven years. These have unearthed sophisticated wooden fish traps and
weirs, as well as fish hooks made from deer bone and harpoons made
from antlers. The remains of literally thousands of bones of butchered
fish suggest the prehistoric diet here was largely cod, flatfish, eels
and dogfish, and, later on, included seals, porpoises and perhaps even
killer whales.
Futher evidence from SINCOS confirms that the shift to seafaring was
accompanied by a transition from nomadic life to a more settled
existence. Large dumps of shells - the remains of harvested oysters,
limpets and scallops - point to prolonged occupation of sites, and
evidence of hunting camps indicate that settlement here was at least
seasonal. It is likely that the inhabitants lived in wooden huts,
although the evidence so far has been sparse.
Momber's work at the Bouldnor Cliff site, near Yarmouth, paints a
similar picture of a settled seafaring existence. Dives in the 1980s
revealed the remains of an ancient forest here, but the real lucky
break came in the late 90s, when archaeologists discovered dozens of
flint tools from early human occupation, unearthed by burrowing
lobsters.
Continued work at Bouldnor Cliff has paid off. The site also yielded
the remains of what is believed to be an ancient log boat, and earlier
this year Momber's team discovered a complex of intersecting timbers
embedded in protective sediment, together with evidence of burnt wood,
flint, pegs and string. Roughly 8150 years old, the timbers feature
distinctive cut marks, a sure sign that they were worked by human
hands. It looks as though the site was an area of specialised
industrial activity, and possibly a waterside platform where boats
could be assembled. If so, Bouldnor Cliff was home to one of Europe's
oldest boatyards, underscoring the advanced craftsmanship of the
Mesolithic people. "It's an absolute gem," says Flemming.
So it seems Mesolithic humans were sophisticated seafarers, but this
existence wasn't to last. Over the next couple of thousand years,
these tribes would face a second, equally monumental shift to farming,
as Neolithic agricultural cultures spread from western Asia across
Europe, finally reaching northern Europe and mainland Britain about
6000 years ago. The exact nature of this transition, though, is
something of a mystery.
"One of the most important questions in prehistoric archaeology is how
this transformation to early agriculture took place," says Benjamin.
"Did migrating Neolithic people replace Mesolithic communities? Did
they interact and trade with each other? Did Mesolithic people adopt
Neolithic practices and technologies from neighbouring regions?"
Going Neolithic bit by bit
Once again, underwater archaeological projects such as SINCOS provide
some clues, if not neat answers. "It's a very complicated picture,"
says SINCOS team member Harald Lübke of the Centre for Baltic and
Scandinavian Archaeology at Schleswig-Holstein State Museum in
Germany. Genetic analyses have produced conflicting results, but the
underwater archaeological record hints at periods of interaction.
"If incoming Neolithic groups simply replaced Mesolithic groups, then
we'd expect to see a rapid change in technology, but this is not what
we see," says Lübke. Instead, it looks as if bit by bit, late
Mesolithic groups assimilated distinctive Neolithic styles of pottery
and flattened axes, as well as domesticated animals and cereals.
The remains of cattle bones suggest that domesticated animals may have
been introduced to coastal Mesolithic life by 6000 years ago, though
fish and seal remains from this time indicate that marine resources
were still important. New types of pottery, imported from south-
eastern Neolithic neighbours, also begin to make an appearance.
"Between 7000 and 6000 years ago, these Mesolithic people adopted some
elements of the Neolithic, such as new ceramics and perhaps imported
cattle, but they didn't immediately change their entire subsistence
system," says Lübke.
It was only later, when people on the Baltic coast came to rely
heavily on domesticated animals such as sheep and goats, that yet more
Neolithic tools, such as polished axes, make their way into the
archaeological record. By 5500 years ago, it seems the transition was
complete, and coastal sites became less important as they were
abandoned in favour of early Neolithic farms.
These results from northern Europe are only the beginning of the
story. Benjamin, for example, has been researching and compiling
geographical, geological and archaeological data in the eastern
Adriatic, where he hopes to find insights into the final stages of the
transition from Mesolithic to Neolithic in this region. "After a lot
of research and preparation, we've isolated a few areas where we think
there should be prehistoric material under water," he says. Others
hope to investigate the coastline of North America to reveal how
tribal peoples migrated across the continent 15,000 years ago.
The best finds may be yet to come, but there is no time to lose. Much
of the submerged Mesolithic treasure which has remained undisturbed in
sediment for thousands of years is disappearing, says Anders Fischer,
an archaeologist with the Heritage Agency of Denmark in Copenhagen.
Construction, dredging and trawling along coastlines are one set of
problems. Then there is pollution, which destroys the underwater
vegetation that helps preserve archaeological sites by stabilising the
sediment. These problems are well documented in the Baltic and may be
just as crucial in coastal waters elsewhere, according to Anders.
Pollution destroys underwater vegetation that helps preserve
archaeological sites
Limited efforts have been made to protect some sites, by covering them
with protective sheets for example. But preventing erosion and damage
to sites on a broad scale around Europe is going to prove extremely
difficult, says Fischer. "If we don't act soon, we're going to lose an
important part of this cultural heritage forever," he says.
Rebuilding the prehistoric world
Underwater archaeology has huge potential, but it is a time-consuming
and costly way to study the past. So resources need to be directed to
the areas where researchers are most likely to hit pay dirt.
In practice, this means reconstructing palaeolandscapes to identify
potential archaeological hotspots. "We're all looking for predictive
models," says Michael Faught, a maritime archaeologist with
Panamerican Consultants in Pensacola, Florida. "We're not going to
simply stumble on these sites."
A first step in narrowing the search is to look for protected offshore
regions - bays and convoluted coastlines - adjacent to land rich in
archaeological material. Areas where little sediment has been laid
down recently are preferable too, as fresh sediment can make accessing
remains difficult.
Sonar is then used to generate maps of the seabed. This information,
in combination with cores from the sea floor, can be used to
reconstruct the submerged landscape and, crucially, to identify
features associated with evidence of human prehistory on land.
Fresh water is a particularly useful clue. "Seventy-five per cent of
archaeological sites are found within 500 metres of rivers," says
Faught.
One of the most important areas to have emerged is Doggerland, the
vast expanse of terrain that joined Britain to mainland Europe 10,000
years ago. With its rich landscape of rivers, lakes and marshes, as
mapped out by Vince Gaffney and Simon Fitch of the University of
Birmingham, UK, it would have been an ideal place for Mesolithic
peoples to settle. Indeed, Doggerland may have been the Mesolithic
heartland of northern Europe, with people hunting, gathering and
fishing in the sort of craft found at Tybrind Vig and Bouldnor Cliff
(see map).
Other features, such as outcrops of chert, a rock resembling flint,
suggest quarries for making stone tools. In his studies of Apalachee
Bay in the Gulf of Mexico off Florida, Faught has looked for such
features to find artefacts crafted by Palaeoindian societies 13,000
years ago. The vast amount of seabed data amassed by oil and gas
companies in regions such as the North Sea has also proved invaluable.
Looking to the future, marine archaeologists still face a key
challenge, namely to develop a global database for future research.
http://www.newscientist.com/article/mg20427351.000-scuba-diving-to-the-depths-of-human-history.html
Hayabusa
<jackli...@earthlink.net> wrote:
Jack,
just wanna say, you are great, thank you.
Hayabusa