Monday, June 15, 2009

A tiny frozen microbe may hold clues to extraterrestrial life

A tiny frozen microbe may hold clues to extraterrestrial life
Jun 14th, 2009 |
A novel bacterium that has been trapped more than three kilometres under glacial ice in Greenland for over 120 000 years, may hold clues as to what life forms might exist on other planets.

Dr Jennifer Loveland-Curtze and a team of scientists from Pennsylvania State University report finding the novel microbe, which they have called Herminiimonas glaciei, in the current issue of the International Journal of Systematic and Evolutionary Microbiology. The team showed great patience in coaxing the dormant microbe back to life; first incubating their samples at 2˚C for seven months and then at 5˚C for a further four and a half months, after which colonies of very small purple-brown bacteria were seen.

H. glaciei is small even by bacterial standards – it is 10 to 50 times smaller than E. coli. Its small size probably helped it to survive in the liquid veins among ice crystals and the thin liquid film on their surfaces. Small cell size is considered to be advantageous for more efficient nutrient uptake, protection against predators and occupation of micro-niches and it has been shown that ultramicrobacteria are dominant in many soil and marine environments.

Most life on our planet has always consisted of microorganisms, so it is reasonable to consider that this might be true on other planets as well. Studying microorganisms living under extreme conditions on Earth may provide insight into what sorts of life forms could survive elsewhere in the solar system.

“These extremely cold environments are the best analogues of possible extraterrestrial habitats”, said Dr Loveland-Curtze, “The exceptionally low temperatures can preserve cells and nucleic acids for even millions of years. H. glaciei is one of just a handful of officially described ultra-small species and the only one so far from the Greenland ice sheet; studying these bacteria can provide insights into how cells can survive and even grow under extremely harsh conditions, such as temperatures down to -56˚C, little oxygen, low nutrients, high pressure and limited space.”

“H. glaciei isn’t a pathogen and is not harmful to humans”, Dr Loveland-Curtze added, “but it can pass through a 0.2 micron filter, which is the filter pore size commonly used in sterilization of fluids in laboratories and hospitals. If there are other ultra-small bacteria that are pathogens, then they could be present in solutions presumed to be sterile. In a clear solution very tiny cells might grow but not create the density sufficient to make the solution cloudy”.

Dianne Stilwell
diannestilwell@me.com
44-795-720-0214
Society for General Microbiology
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Saturday, June 13, 2009

Incisions on ochre from a South African cave suggest modern human behavior emerged around 100,000 years ago

Designs on pigment can be seen at the citation/cite.

Engraved pigments point to ancient symbolic tradition
Incisions on ochre from a South African cave suggest modern human
behavior emerged around 100,000 years ago
By Bruce Bower
Web edition : 1:03 pm


Line designsGeometric patterns incised on pieces of ancient pigment,
such as these 100,000-year-old finds, may reveal the surprisingly
ancient origins of modern human behavior.Courtesy of C. Henshilwood
and F. d’Errico


Scientists excavating a Stone Age cave on South Africa’s southern
coast have followed a trail of engraved pigments to what they suspect
are the ancient roots of modern human behavior.


Analyses of 13 chunks of decorated red ochre (an iron oxide pigment)
from Blombos Cave indicate that a cultural tradition of creating
meaningful geometric designs stretched from around 100,000 to 75,000
years ago in southern Africa, say anthropologist Christopher
Henshilwood of the University of the Witwatersrand in Johannesburg and
his colleagues. Their report appears online and in an upcoming Journal
of Human Evolution.


Much debate surrounds the issue of when and where language, religion,
symbolic decorations and other facets of modern human behavior
originated. Researchers such as Henshilwood hypothesize that modern
human behavior developed gradually in Africa, beginning more than
100,000 years ago. Others posit that a brain-boosting genetic mutation
around 50,000 years ago fostered modern behavior in Africa. Some
researchers suspect that behavioral advances first appeared in Europe,
Asia and Africa at that later time.


Possible examples of symbolic behavior from around 100,000 years ago —
such as proposed human burials in the Middle East and pigment use in
Africa — have been controversial.


“What makes the Blombos engravings different is that some of them
appear to represent a deliberate will to produce a complex abstract
design,” Henshilwood says. “We have not before seen well-dated and
unambiguous traces of this kind of behavior at 100,000 years ago.”


Further studies need to confirm that the ancient incisions were not
the result of, say, slicing into ochre with stone tools in order to
remove powder quickly, cautions anthropologist Curtis Marean of
Arizona State University in Tempe, who studies ancient human behavior
at another South African cave (SN: 10/20/07, p. 243).


Even if the Blombos pigments contain intentional designs, fully modern
human behavior — such as the use of figurative art (SN: 6/20/09, p.
11)  — didn’t emerge until tens of thousands of years later, contends
archaeologist Nicholas Conard of the University of Tuebingen, Germany.


Henshilwood and study coauthor Francesco d’Errico of the University of
Bordeaux I in Talence, France, disagree. In their view, the Blombos
pigments bear intentionally fashioned designs that held some sort of
meaning and were passed down the generations for 25,000 years. Thus,
the two researchers say, it’s likely that a 100,000-year-old society
already steeped in symbolic behavior originally produced the ochre
engravings.


In 2002, Henshilwood’s team described evidence of symbolic engravings
on two other ochre pieces from Blombos Cave. Those 77,000-year-old
finds were excavated in 1999 and 2000.


Engraved chunks of pigment in the new analysis were unearthed during
the same excavations. Specimens came from either of three sediment
levels with estimated ages of 72,000 years, 77,000 years and 100,000
years.


A microscopic analysis indicates that ochre designs were made by
holding a piece of pigment with one hand while impressing lines into
the pigment with the tip of a stone tool. On several pieces, patterns
covered areas that had first been ground down.


Geometric patterns on the ochre pieces include cross-hatched designs,
branching lines, parallel lines and right angles.


Pigment powder had also been removed from many of the recovered ochre
chunks. Incised patterns may have served as models for pigment designs
applied to animal skins or other material, the scientists speculate.


Excavations of Blombos Cave sediment from before 100,000 years ago
have begun. “The discovery of more, and perhaps even more striking,
engravings is very possible,” Henshilwood says.

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Tuesday, June 9, 2009

Archeological Evidence Of Human Activity Found Beneath Lake Huron

ScienceDaily (June 9, 2009) — More than 100 feet deep in Lake Huron, on a wide stoney ridge that 9,000 years ago was a land bridge, University of Michigan researchers have found the first archeological evidence of human activity preserved beneath the Great Lakes.



The researchers located what they believe to be caribou-hunting structures and camps used by the early hunters of the period.

"This is the first time we've identified structures like these on the lake bottom," said John O'Shea, curator of Great Lakes Archaeology in the Museum of Anthropology and professor in the Department of Anthropology. "Scientifically, it's important because the entire ancient landscape has been preserved and has not been modified by farming, or modern development. That has implications for ecology, archaeology and environmental modeling."

A paper about the findings is published in the Proceedings of the National Academy of Sciences. Co-authors are O'Shea and Guy Meadows, director of the Marine Hydrodynamics Laboratories and a professor in the departments of Naval Architecture and Marine Engineering, and Atmospheric, Oceanic and Space Sciences.

O'Shea and Meadows found features that they believe to be hunting pits, camps, caribou drive lanes and stone piles used to attract the caribou to the drive lanes. Drive lanes are long rows of rocks used to channel caribou into ambushes. The 1,148-foot structure they believe is a drive lane closely resembles one on Victoria Island in the Canadian subarctic.

The hunting formations are on the 10-mile-wide Alpena-Amberley ridge that stretches more than 100 miles from Point Clark, Ontario to Presque Isle, Michigan. The ridge was a bridge between 10,000 and 7,500 years ago when water levels were much lower. Its surface is relatively unspoiled, unlike coastal areas where scientists believe other archeological sites exist. These coastal sites would now be deeply covered in sediment, so they're often considered lost forever.

Scientists have hypothesized for some time that the ridge might hold signs of ancient occupations. But they didn't know what signs to look for. O'Shea and Meadows zeroed in on caribou-hunting structures after considering the region's climate at the time, which would have been similar to the subarctic. Subarctic hunters are known to utilize caribou drive lanes.

The U-M researchers then narrowed down where to look for these structures by modeling the lake ridge as it would have been when it was dry. They worked with a Robert Reynolds a professor of computer scientist at Wayne State University to reconstruct the ancient environment and then simulate caribou migrations across the corridor. Based on this, they picked three spots to examine.

O'Shea and Meadows used U-M's new, cutting-edge survey vessel Blue Traveler, sonar equipment and underwater remote-operated vehicles with video cameras to survey these areas.

"The combination of these state-of-the art tools have made these underwater archeological investigations possible," Meadows said. "Without any one of these advanced tools, this discovery would not have happened."

Archaeologist will begin examining these areas this summer.

The Paleo-Indian and early Archaic periods are poorly known in the Great Lakes region because most of their sites are thought to have been lost beneath the lakes. Yet they are also times of major shifts in culture and the environment.

The Paleo-Indians were nomadic and pursued big game, O'Shea said. With the Archaic period, communities were more settled, with larger populations, a broad spectrum economy, and new long distance trade and ceremonial connections.

"Without the archeological sites from this intermediate time period, you can't tell how they got from point A to point B, or Paleo-Indian to Archaic," O'Shea said. "This is why the discovery of sites preserved beneath the lakes is so significant."

Perhaps more exciting than the hunting structures themselves is the hope they bring that intact settlements are preserved on the lake bottom. These settlements could contain organic artifacts that deteriorate in drier, acidic soils on land.

The research is funded by the National Science Foundation.
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Monday, June 8, 2009

A Storm of Swords


This was probably the most action packed, as well as tragic, of the first three books, where many breath-holding subplots finally get their resolve after over 3000 pages of series, where age old conflicts come to climax, elusive secrets finally get revealed, and the true character of many enigmatic figures comes to light.
Here Martin succeeds in dashing virtually every hope of the armchair fan about two thirds through the book, no matter who he or she has been rooting for, but at the same time proves his writing mastery by keeping the reader from throwing the book down in utter disgust by the sheer power of several intriguing subplots that reader may not have even realized that he cared about until Martin so deftly and punctually turned up the flame.
Alot has been written about analogies in this series to the War of the Roses, using the literary device called "Historical Criticism," but in order to offer something new by way of review I would herein also like to put the book under the scrutiny of what I'll call "Prehistoric Criticism."
In a nutshell, this series can also be equated to the Pleistocene Ice Age of Europe, where winters really did last for hundreds or even thousands of years. The giants and children of the forest could well be seen as Neanderthals and/or other archaic humans, or possibly even the earliest so-called Cro-Magnons, or Aurignacions.
The First Men would be the tale end of the Aurignacion, or possibly the Gravettian, whereas the Andals represent later cultures such as the Solutrean (despite the Andal's metallurgy) or even the far later "Iron Age."
The Wall could be seen as a memory of the great glaciers that once lay across Europe, and for millenia seperated "Upper Paleolithic" homo sapien from the neanderthals, and later seperated both the Aurignacions and neanderthals from the invading Gravettians for a time.
If we are to look at the book as a memory of the real age of myth and legend, which some believe is the Pleistocene Ice Age, then The War of the Roses takes a back seat; since we have no details of the political history of Ice Age Europe, Martin had to create a probable one. And since history repeats itself, why not draw influence for the the sordid details of clan warfare from one of the ugliest snapshots of human pettiness and depravity we have available to us, The War of the Roses?
Surely Martin shows us here that Houses and Banners are no more civilized than Clans and Totems, and that both caves and castles can house the barbary of man.
And of course, Valyria can be equated to Atlantis and the Ironmen to the predecessors of the Vikings.
Further, Martin seems to have used more than just the War of the Roses to bring political life to this mythical memory of the Ice Age; to name just one instance, Oldtown with it's cobblestone streets and bribe to the Andlas reminds me much of my hometown of Savannah and it's similar bribe to Sherman...and being a decently well-off American Martin is sure to have heard the spiel of the tour guides from the Hostess City of the South on a vacation sometime in his life.
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Thursday, June 4, 2009

Ancient Art, Music Flowered as Communities, Not Brains, Grew

The other side of that coin:

“They have it wrong,” Klein said in a telephone interview. “This paper
does not belong in print.”


Klein is a proponent of a competing theory that attributes the
development of modern human behavior to a genetic change to human
brains 50,000 years ago.


“These behaviors appear to have been part of a package that
significantly enhanced human fitness -- the ability to survive and
reproduce,” Klein wrote in a study that was published last year in the
journal Evolutionary Anthropology. “It is in this sense that they
signal true evolutionary change as opposed to mere historical
change.”


Ancient Art, Music Flowered as Communities, Not Brains, Grew


By Ryan Flinn


June 4 (Bloomberg) -- An explosion of art, music, jewelry and hunting
technology appeared 45,000 years ago because of increased population
density, rather than the evolution of the human brain, a study said.


Researchers used genetic estimates of ancient population sizes,
archaeological artifacts and computer simulations of social learning.
They found complex skills involving abstract thinking would be passed
down through generations and across groups only when populations reach
a critical level, according to the study in tomorrow’s edition of the
journal Science.


Increased interaction between groups, the sharing of ideas and the
exchange of raw materials that led to the flowering of human culture
may explain why concentrated centers of industry, such as California’s
Silicon Valley, produce technological innovations, said Mark Thomas,
44, a senior author of the study and a senior lecturer at University
College London in England.


“People learn from their parents or teachers in their group, and this
model demonstrates you have to have a critical number of people
learning to develop complexity,” Adam Powell, 28, a co-author of the
study and a doctoral student at the London university. “The actual
invention of all these technologies was probably very common, but was
only passed on as density increased.”


45,000 Years Ago


Anatomically, modern humans have been around for an estimated 200,000
years, yet scientists have found the first widespread evidence of
sustained symbolic behavior and abstract thinking emerged about 45,000
years ago. The findings include musical instruments, body decoration
with shell beads and tattoos, bows and arrows and microlithic stone
blades, according to the study.


An ancient example of figurative art was discovered recently in a
German cave, depicting a woman with enlarged breasts and genitals,
Powell said. One of the oldest of its kind, it dates back 35,000 years
ago, according to a May 14 study published in the journal Nature.


Powell said his study may explain why modern human behavior appeared
to emerge in different regions of the world at different times.
Evidence was seen sporadically as far back as 90,000 years ago in sub-
Saharan Africa, with a more sustained pattern 40,000 years ago, and in
Europe and western Asia 45,000 years ago. Archaeological samples
indicating similar skills were found in eastern and southern Asia and
Australia 30,000 years ago. Population densities would have reached a
critical point in sub-Saharan Africa and Europe at about the same time
periods, according to the study.


Popular Illustrations


The impetus for human development has been pondered throughout
history, Thomas said in an interview. The 1968 film, movie “2001: A
Space Odyssey,” illustrated the mystery with a scene of a symbolic
monolith slab on an ancient landscape that enabled humanlike apes to
make tools and think critically.


“In reality, what I suspect is these technologies were being invented
all the time, but they never hung on for more than a few generations.
You need sustained evidence for it to be visible in archaeological
record.”


Not everyone is convinced the demographic model caused the behavioral
change. Richard Klein, an anthropology and biology professor at
Stanford University, said the study is flawed because the examples it
cites of human behavior prior to 50,000 years ago are either misdated
artifacts or are open to interpretation as to their level of
advancement.


Competing Theory


“They have it wrong,” Klein said in a telephone interview. “This paper
does not belong in print.”


Klein is a proponent of a competing theory that attributes the
development of modern human behavior to a genetic change to human
brains 50,000 years ago.


“These behaviors appear to have been part of a package that
significantly enhanced human fitness -- the ability to survive and
reproduce,” Klein wrote in a study that was published last year in the
journal Evolutionary Anthropology. “It is in this sense that they
signal true evolutionary change as opposed to mere historical
change.”

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The study of time as it relates to archaeology is, to coin a phrase,

The study of time as it relates to archaeology is, to coin a phrase,
moving right along. The pottery clock, the various "rock" clocks,
added to the radiocarbon system now have a companion in the
examination of the entire mtDNA molecule.

"We can settle the debate regarding mankind's expansion through the
Americas. Researchers have been estimating dates from mtDNA that are
too old for the archaeological evidence, but our calculations confirm
the date to be some 15,000 years ago, around the time of the first
unequivocal archaeological remains.


"Furthermore, we can say with some confidence that the estimate of
humanity's 'out of Africa' migration was around 60-70,000 years ago –
some 10-20,000 years earlier than previously thought."


New 'Molecular Clock' Aids Dating Of Human Migration History


ScienceDaily (June 4, 2009) — Researchers at the University of Leeds
have devised a more accurate method of dating ancient human migration
– even when no corroborating archaeological evidence exists.


Estimating the chronology of population migrations throughout
mankind's early history has always been problematic. The most widely
used genetic method works back to find the last common ancestor of any
particular set of lineages using samples of mitochondrial DNA (mtDNA),
but this method has recently been shown to be unreliable, throwing 20
years of research into doubt.


The new method refines the mtDNA calculation by taking into account
the process of natural selection - which researchers realised was
skewing their results - and has been tested successfully against known
colonisation dates confirmed by archaeological evidence, such as in
Polynesia in the Pacific (approximately 3,000 years ago), and the
Canary Islands (approximately 2,500 years ago).


Says PhD student Pedro Soares who devised the new method: "Natural
selection's very gradual removal of harmful gene mutations in the
mtDNA produces a time-dependent effect on how many mutations you see
in the family tree. What we've done is work out a formula that
corrects this effect so that we now have a reliable way of dating
genetic lineages.


"This means that we can put a timescale on any part of the particular
family tree, right back to humanity's last common maternal ancestor,
known as 'Mitochondrial Eve', who lived some 200,000 years ago. In
fact we can date any migration for which we have available data," he
says.


Moreover, working with a published database of more than 2,000 fully
sequenced mtDNA samples, Soares' calculation, for the first time, uses
data from the whole of the mtDNA molecule. This means that the results
are not only more accurate, but also more precise, giving narrower
date ranges.


The new method has already yielded some surprising findings. Says
archaogeneticist Professor Martin Richards, who supervised Soares: "We
can settle the debate regarding mankind's expansion through the
Americas. Researchers have been estimating dates from mtDNA that are
too old for the archaeological evidence, but our calculations confirm
the date to be some 15,000 years ago, around the time of the first
unequivocal archaeological remains.


"Furthermore, we can say with some confidence that the estimate of
humanity's 'out of Africa' migration was around 60-70,000 years ago –
some 10-20,000 years earlier than previously thought."


The team has devised a simple calculator into which researchers can
feed their data and this is being made freely available on the
University of Leeds website.
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University of Florida: Epic carving on fossil bone found in Vero Beach Options

University of Florida: Epic carving on fossil bone found in Vero Beach


BY SANDRA RAWLS, CORRESPONDENT
© 2009, VERO BEACH 32963


In what a top Florida anthropologist is calling “the oldest, most
spectacular and rare work of art in the Americas,” an amateur Vero
Beach fossil hunter has found an ancient bone etched with a clear
image of a walking mammoth or mastodon.


According to leading experts from the University of Florida, the
remarkable find demonstrates with new and startling certainty that
humans coexisted with prehistoric animals more than 12,000 years ago
in this fossil- rich region of the state.


No similar carved figure has ever been authenticated in the United
States, or anywhere in this hemisphere.


The brown, mineral-hardened bone bearing the unique carving is a foot-
long fragment from a larger bone that belonged to an extinct “mammoth,
mastodon or ground sloth” according to Dr. Richard C. Hulbert, a
vertebrate paleontologist at the Florida Museum of Natural History
museum. These animals have been extinct in Florida for at least 10,000
years.


Etched into the bone by a highly sharpened stone tool or the tooth of
the animal is the clear image of a walking adult mammoth or mastodon.
Extensive tests over the past two months have shown that the image was
created when the bone was fresh, presumably right after the animal it
belonged to was killed or died.


Experts who have examined the bone, found at a location which has not
been publicly disclosed on the northern side of Vero Beach, concluded
the carving and surface are of the same age – 12,000 to 14,000 years
old — with no evidence of recent tampering (see accompanying story on
tests that have been performed to date).


Dr. Barbara Purdy, professor emerita of Anthropology at the University
of Florida, on May 19th told Vero Beach 32963 discovery of an image
carved into a bone by a prehistoric human is unprecedented in North
America, and she called the find by fossil hunter James Kennedy “the
oldest, most spectacular, and rare work of art in the Americas.”


“Never before in the Western Hemisphere, has there been a bone from an
extinct species incised with a recognizable picture of an animal,”
Purdy went on. “It would be ancient evidence that people living in the
Americas during the last Ice Age created artistic images of the
animals they hunted.”


The four-inch etching of the elephant appears faintly but clearly on
the surface of a fossil bone. The image, small yet showing the
perspective of one rear leg in front of the other, a dangling trunk
and a hint of a squinting eye, was apparently made by a prehistoric
resident of south central Florida.


The eyes of specialists around the world are now focused on the bone
and image as they subject it to every sort of analysis to determine
authenticity and consider its origins.


Purdy, a curator emerita in archaeology at the Florida Museum of
Natural History, has been overseeing the effort to painstakingly
examine the carving. As results from over a dozen specialists
accumulated, and her excitement and conviction of its authenticity
increased, she prepared to release news of the find to the scientific
community at large.


“I did everything in my power to show this thing was a fake. I was not
going to stick my neck out on something this rare unless I was as sure
as you can be in science.”


After sending out photos and detailed reports from University of
Florida labs, Purdy’s email box was soon filled with reactions from
her colleagues.


World renowned geochemist Thomas Stafford commended Purdy with
eloquence on her efforts from his lab in Colorado.


“You have done true and intense due diligence in determining whether
or not the object is ancient and therefore science is on your side,”
he said in the email read by Purdy to Vero Beach 32963. “If later
interpretations agree or disagree with your and others present
opinions, it is just the wondrous process of science, by which we
asymptotically approach truth. Sometimes this takes a few hours in the
case of a mathematical proof; sometimes it takes centuries in the case
of discerning evolution’s inner workings.”


In Britain, Dr. Paul G. Bahn, an archaeologist with a doctoral degree
from the University of Cambridge, is a specialist in prehistoric art;
he led the team that discovered the first Ice Age cave art in Britain
in 2003 and 2004. Purdy included him in the loop of information on the
Vero bone, and shared his reaction with Vero Beach 32963 as well.


It shows the requisite scientific skepticism of finds as rare as this,
and at the same time, his optimism that an amazing discovery has
indeed been made in Vero Beach. “When you see something like this,
your first thought is that it must be a fake. But there has to be a
first time, and this might be it.”


Dr. C Andrew Hemmings, an archaeologist at the University of Texas at
Austin, is a specialist in the Paleoindian period of prehistory and in
bone and ivory tools. He is especially interested in aspects of
ancient Florida, and has worked at underwater sites in the Aculla
River. He is currently working on an excavation off the west coast
near Tampa, and took a break from his work to send his approbation.


“Andy was cute,” Purdy says. “He took all my reports and said, ‘This
certainly looks like a perfectly good mammoth carving to me.’”


Meanwhile, Kennedy, the amateur finder of the fossil, is stunned at
the significance of his almost chance discovery of the etching. An
avid and longtime fossil hunter born and raised in Vero Beach, Kennedy
found the bone as long ago as four years in a northern area of the
city. He kept the bone fragment in a box at his home along with others
he had found, still caked with soil in places, awaiting closer
inspection.


One day in February, he closely examined the bone, wiping fine dirt
from the thick fragment. As he cleaned it carefully under the bright
light of a work table lamp, suddenly he saw a distinctive shape carved
into the smooth, curved side of the dark surface. Like a face arising
suddenly from a visual puzzle, the appearance of the animal image took
him by surprise.


The clear outline of a striding elephant with large tusks appeared
beneath the bright light. He knew he had something important in his
hands. Here was something more than man and mammoth together, but a
personal expression, a work of art or perhaps a religious presentation
from a lost and distant world thousands of years in the past.


“I knew this was the coolest thing I had ever found,” says Kennedy. “I
was holding something somebody made thousands of years ago.”


Kennedy immediately called an old friend, Vero attorney Gene
Roddenberry. A member of the Historical Society, Roddenberry had
helped James with other finds the younger man had made over the years.
A large mammoth tooth he found in the main canal as a teenager was
donated to the city museum, and other large bones had been donated to
the University of Florida.


Both men knew the carving needed to go quickly to Gainesville, the
state university system being the base of leading experts in
prehistoric Florida.


Right away, scientists wondered at so rare a find: Could the image
have been carved more recently into the rock-hard surface of the bone
that is at least 10,000 years old? Could an indigenous Floridian from
even the last millennium have chiseled an image of a creature that
disappeared with the Ice Age?


The image looked old and worn and seemed similar to European cave
paintings and to artifacts found far from the Americas, but was it
authentic?


The bone, currently housed in a vault locally, first went to Barbara
Purdy in early April. Even specialists can be fooled, but to her eyes,
it looked quite real. “The thing that struck me at the beginning was,
unlike forgeries generally, the image is not deep,” Purdy says. “It
could easily be missed. It looked naturally worn, the way a coin does
that has been handled a great deal, the image beginning to fade.”


Dr. Michael Warren, forensic anthropologist and director of the C.A.
Pound Human Identification Laboratory at the University of Florida,
has studied the incisions that form the image and the surface of the
bone, and has found both to be “ancient.”


In May, Dr. Kevin Jones, the chairperson of the Material Science and
Engineering Department at the University of Florida, as well as two
other scientists working with him there, also examined the carving.


Using a method called energy dispersive X-Ray spectroscopy and a
scanning electron microscope, they were able to study the object in
tremendous detail. All three scientists concluded that both the
carving and the bone’s surface were the same age, with no evidence of
recent tampering.


Around the country and abroad, Purdy sought out experts in Upper
Paleolithic art, Late Pleistocene geology, paleontology and
Paleoamerican archeology. She asked them to examine photographs and an
electron microscope picture of the bone and carved image. None so far
has voiced a reason to doubt the object’s authenticity, although tests
and examinations continue.


One test, a rare earth element analysis, is expected to be concluded
this week to determine where in Florida’s geological strata or layers
the bone was originally located. This powerful new method utilizes the
process of fossilization itself.


When bones become fossilized, calcium is slowly replaced by minerals
including rare earth elements like scandium and cerium. Bone takes up
these rare earth elements, or REEs, in direct proportion to the amount
present in the particular strata of earth where the bone was
originally located.


This gives the bone a unique REE signature that confirms the earth
layer where a bone originally lay and gives an idea of its age.
Scientists can then compare the results to those of others fossil
bones found in similar settings in Vero Beach.


The discovery of the etching brings a vivid clarity to the idea that
early humans lived in our county among the extinct animals of
Florida’s Pleistocene epoch.


The Pleistocene spanned from 1.8 million to about 10,000 years ago.
Many types of trees, mosses, insects, mollusks, flowering plants,
birds, and mammals survive today from the last years of that era.


The Pleistocene was also characterized by large land mammals. Mammoths
and their cousins the mastodons, as well as bison, llamas, saber-
toothed cats, giant ground sloths, and other large animals, roamed the
then-drier landscapes of Florida.


Native horses and camels galloped across Florida grasslands that
resembled today’s African savannahs. They disappeared at the end of
the last Ice Age with the advent of a wetter climate. Shorelines
retreated to what they are today as water held in ice returned to the
seas.


No one knows when the first people arrived in Florida, or how many
waves of such people may have lived here as climate and geography went
through tremendous changes.


The first inhabitants of North America were small groups of nomadic
huntergatherers; few signs of their existence have been found. Most
linguists and physical anthropologists believe these people originally
came primarily from Siberia. Moving eastward across the wide Bering
land bridge known as Beringia, they may have arrived in North America
as much as 30,000 years ago or even before.


The earliest people’s remains and artifacts are rare amid the more
abundant evidence of those who lived much later. In Florida, rapid
commercial development has sometimes led to disruption or even
destruction of fossil sites. When professionals are called in,
sometimes they must work in haste as projects want to push forward.


Despite that, a wealth of spearheads, knives, blades, scrapers and
other tools made of stone, as well as tools made of ivory or the bones
of extinct animals have been found throughout the United States and
from Florida. Yet, nothing like the carved mammoth image has ever been
found. Such evidence of artistic representation is known from the
caves of Europe and the steppes of Asia, but not North America.


This is hardly the first time an important fossil find has occurred
here. Amateur fossil hunters other than James Kennedy have found the
bones of large Pleistocene mammals at various locations around the
county.


The unique characteristics of Florida’s geology account for this
improbable sounding reality. The peninsula is formed entirely of
sedimentary rock lying upon a foundation of thick limestone. The
limestone was laid down when the state was covered by shallow seas
between 65 and 20 million years ago.


There are no dinosaur fossils in Florida, but plentiful mammals are
often discovered in old streambeds and sinkholes. Fresh water was more
scarce during the Pleistocene than today, and animals and people
flocked to sources of the precious liquid. These circumstances mean
that mammal fossils are not generally encased in rock or found deep
below the surface as they can be elsewhere.


Vero Beach is already one of the best known and most discussed fossil
sites in Florida, producing two fossilized partial skeletons, the
older of which became known as Vero Man.


Isaac M. Weills and Frank Ayers found the fossil human bones here
nearly 100 years ago where the Indian River Farms Company was
constructing a drainage canal that intersected the old streambed of
Van Valkenburg Creek.


The site is near U.S. One and the new county administration complex. A
great number of extinct mammal bones were also found along the old
creek-bed, including the first find of a sub-species of North American
tapir that would be named after its location: Tapirous veroensus.


Years of contention about the age and nature of the partial sets of
human bones followed.


Although the anthropologists and paleontologists who study the
Pleistocene have long agreed about the co-mingling of early human
groups and extinct mammals in Florida, questions lingered over the old
local finds.


Back in 1915 some scientists questioned whether the bones of Vero Man
were carried into deposits older than the bones actually were, by
accidental mixing of ground layers or other means. Skull measurement
techniques, since discredited, were used by one scientist to estimate
the age of the bones, and contradict a Florida geologist who said Vero
Man was much older, a premise now widely held.


The bones and skull were dated at the time by acclaimed state
geologist Elias Sellards as being at least 10,000 years old. The
bones’ antiquity was questioned by Ales Hrdicka of the Smithsonian
Institution who believed they were much younger. He asserted the
heavily mineralized human bones, clearly fossils, were of recent
origin. His view was the fossilization had happened quickly and humans
never lived here in the Pleistocene.


Over the next 30 years the bones and skull were housed by numerous
persons and institutions. There was even some evidence the bones had
actually belonged to a woman and not a man. The skull was cast in
cement, damaged, and then disappeared. Femurs and the other remaining
bones today are scattered at different state institutions and at the
Smithsonian in Washington D.C.


Although Sellard’s assessment is now generally accepted, there are
still those who have questioned the presence of man living here with
the great mammals long gone. James Kennedy’s discovery appears to
offer unequivocal evidence that human beings lived in our area during
the Pleistocene, and that Sellards analysis was likely correct.


Barbara Purdy has spent years studying and analyzing the earliest
Floridians and the evidence they left behind. Her most recent book,
“Florida’s People during the last Ice Age,” released last year, offers
an overview of the last 100 years of research into Florida’s earliest
people.Fossil sites and finds in Vero Beach and Melbourne are among
the many she describes in detail.


Purdy would like to see a new, more complete excavation of the old
Vero site that has continued to yield fossil animal bones and human
artifacts like spear points. She calls for a new “well-designed
project incorporating the expertise of individuals from various
disciplines using 21st century techniques.” She estimates a thorough
scientifically executed excavation would cost around $150,000.


“What we need down there requires going down eight feet or more into
the deposits,” she says. “All material needs to be screened with fine
mesh. It all needs to be carefully done, not contract archeology, but
a painstaking University-type project.”


The question of pre-historic man living here during the late
Pleistocene now may be resolved, but scientists wonder what other
finds might be discovered. The famous site of Vero Man, where human
fossils were first found, will likely be disrupted this year due to
expansion of the Vero Beach water plant. Other scientists interested
in the age of bones and the surrounding sediments found there plan to
begin work in June. Any excavation will be the last opportunity to
properly examine the site before the water plant project.


Sometimes people do find the thing that dreams are made of. For
Barbara Purdy and James Kennedy, the image under the light in February
revealed a once in a lifetime discovery. The elephant carving will
bring new interest in the geology and fossil beds of Indian River
County. Hopefully the bone will find a permanent home at the Natural
History Museum of the University of Florida.


This extraordinary and rare piece of human history will put Vero Beach
in textbooks for years to come. Stories will be written and more
extensive explorations will certainly follow. Barbara Purdy dedicated
her recent book to Elias Sellards whom she calls “a visionary.”


Today, with amateurs and pros looking at an old bone and an ancient
hand’s depiction of an awesome beast, he would certainly be smiling.


What experts say


Dr. Kevin S. Jones, chairperson of the University of Florida
Department of Materials Science and Engineering:


“I am quite convinced this carving is genuine. Nothing we know here
indicates anything other than great age for both the bone and the
drawing. The image is hard to see and does not stand out, the way you
think it might if it had been created for that purpose. But more
importantly the coloration, the degradation of the image, and wear
patterns inside and outside the cut surfaces are completely
consistent. I feel along with my colleagues J.J. Mecholsky and Gerald
Borne, who have also worked on it, that this image is very ancient.
The results we got from the Energy Dispersive X-ray spectroscopy
analysis of the surface conducted in a scanning electron microscope
eliminate any possibility a polymer coating was used to make the
inside and outside of the cuts look the same. I am very comfortable
saying that this bone and its image are both very old.”


Dr. Michael W. Warren, forensic anthropologist and Director of the
C.A.Pound Human Identification Laboratory at University of Florida:


“In my line of work, we try to be quite conservative in our
statements. I worked on this image in the bone with our cut mark
specialist Dr. Laurel Freas. What you see in this image are cut marks
eroded over a very long period of time. There are no distinct edges
and they are worn and eroded in a manner not only consistent with a
long process but exposure to water. The appearance is of gradual
alteration has been going on a very long time. It was exciting for us
to work on this because it became more and more clear that it was an
authentic image of great age.”


James Kennedy: ‘I’ve always been good at finding things’


James Kennedy’s first fossil might have jumped up and bit him, as the
saying goes, but for the old cement mixing tub he was floating in,
down a canal just north of downtown Vero Beach.


He was sixteen years old, and taking a break in a day of fishing.
Suddenly, the bottom of the tub hit a bump. The boy hopped out to
investigate. Where the tub had scraped, a large, layered tooth of a
mammoth, rock- hard, with a surface of serpentine folds, emerged from
the sandy water.


Kennedy could hardly imagine what his wet hands held: a piece of the
very body of a massive Ice Age mammal, a beast that had trumpeted and
thundered up some prehistoric precursor to nearby US 1. For James
Kennedy it was a revelation, and the beginning of a ceaseless quest.


The cement tub is long gone, but Kennedy has never stopped searching,
digging in canals, riverbanks, and old streambeds across the
geologically unique landscapes of Florida, among the richest fossil
beds in the country.


The arid scrub-covered ridge along Old Dixie Highway and US 1, visible
between Fort Pierce and Vero Beach, was once an ancient shoreline, one
of several left in Florida where the rising and falling tides caused
by ice sheets far away left crests of higher ground. But it is the
rare watering holes of fresh water that mammals — including people —
congregated near, undulating old stream beds often just four to eight
feet beneath the surface today, where many remains still lie.


James Kennedy, 39, was born and raised in Vero. Through a tight-knit
network of supporters of his passion, he has persevered as doggedly as
anyone in a field of highly trained specialists. With books and
computer, pamphlet and lecture, he has learned about the lost past of
ancient Florida.


And he has more than that. He has instincts, maybe even a sixth sense
of how people and animals got around here in Vero a very long time
ago.


Amateur fossil hunters like James Kennedy have always been important
in the discovery of valuable artifacts. “Sue”, the gigantic
Tyrannosaurus now at the Chicago Field Musuem, was found by an
amateur, Sue Hendrikson. Locally, lore has it that much of a mastodon
sits in a middle-class Vero home, unearthed from a local site, and
million-dollar homes sit on fossil beds where many a bone or spearhead
has turned up in swales and ditches.


“You wouldn’t believe some of the things I’ve seen,” says Kennedy,
sitting at his work table littered with bones, books, and tools.
Plastic cigarette lighters and an ashtray sit next to a spear point
and several fossil vertebrae.


From his finds he has learned to imagine, and reconstruct scenarios of
prehistory.


“Up on one of the northern rivers, there is a place with a bluff and a
big hole underwater where a whole bunch, and I mean a big bunch, of
mammoth and mastodon bones are,”


he says. “It looks clear to me checking out some of those bones, they
might have been driven there and slaughtered by people long ago, just
like a butcher room for a kitchen”.


Kennedy has been resourceful when money was hard to come by for
supplies. He seems to retain good friends; some are earnest and eager
to help.


“Everybody that knows me knows how much I love this stuff,” he says.
“I know a private land owner who’s let me dig around on his property
where there are quite a few fossils. He gave me a birthday present of
permission to dig over there. People just know that is what I love to
do.”


While researchers often use calibrated brass sifters, Kennedy’s tools
are ambitious if makeshift methods to aid in his searches.


“I’ve made myself all sorts of sifters, wire screen sifters and things
like that, to help look for bones,” Kennedy says. “I wanted to control
the water pressure,” he said. “So I took a small water pump, and a
three-horse-power engine, some PVC pipe, and wire, and a garden hose,
and I made this thing to wash away sand.”


Sometimes a site draws him back again and again, like a superstition
makes a child skip over cracks.


“I get an itch to go, and I go,” he says. “I’ve been to some places a
hundred times in a year.”


“I’ve always been good at finding things, all my life,” he says. “I
have a sort of instinct, a kind of gut feeling about whether or not
something is going to turn up.”


He toys with a cardboard box of bone pieces and giant sharks teeth he
has pulled out of a drawer. Kennedy lives in a quiet area of South
Vero near his mother. It is from her, some say, that he inherited a
keen insight to the past and future.


James Kennedy claims to have his own cataloguing methods that allow
him to keep track of his many digs and finds.


He was not prepared for the news that greeted him in Gainesville about
the extreme rarity of the carved elephant image.


Nor was his friend, Gene Roddenberry, a local attorney with a long,
deep interest in Vero’s history, who had driven Kennedy and the etched
bone up to Gainesville and Dr. Barbara Purdy for initial analysis.


The result could not have been more reassuring. Purdy and the UF
scientists were in full discovery mode, excited and anxious to apply
all the methods of current science to confirm or deny the extreme
rarity of the drawing and its possible enormous significance.


The news of just how rare their find appeared to be left Kennedy and
Roddenberry completely agog.


“I was in shock,” said Kennedy. “I mean, I just had no idea how few
things like that there are. Gene was with me and we started talking
about it, the magnitude of it. And Gene is very well-spoken,” said
Kennedy. “But he almost started stuttering. We were both in shock.”

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Ha-Ha! Ape study traces evolution of laughter

When scientists set out to trace the roots of human laughter, some chimps and gorillas were just tickled to help. Literally.

That's how researchers made a variety of apes and some human babies laugh. After analyzing the sounds, they concluded that people and great apes inherited laughter from a shared ancestor that lived more than 10 million years ago.

Experts praised the work. It gives very strong evidence that ape and human laughter are related through evolution, said Frans de Waal of the Yerkes National Primate Research Center at Emory University in Atlanta.

As far back as Charles Darwin, scientists have noted that apes make characteristic sounds during play or while being tickled, apparently to signal that they're interested in playing.

It's been suggested before that human laughter grew out of primate roots. But ape laughter doesn't sound like the human version. It may be rapid panting, or slower noisy breathing or a short series of grunts.

So what does that have to do with the human ha-ha?

To investigate that, Marina Davila Ross of the University of Portsmouth in England and colleagues carried out a detailed analysis of the sounds evoked by tickling three human babies and 21 orangutans, gorillas, chimps and bonobos.

After measuring 11 traits in the sound from each species, they mapped out how these sounds appeared to be related to each other. The result looked like a family tree. Significantly, that tree matched the way the species themselves are related, the scientists reported online Thursday in the journal Current Biology.

They also concluded that while human laughter sounds much different from the ape versions, its distinctive features could well have arisen from shared ancestral traits.

Jaak Panksepp of Washington State University, who studies laughter-like responses in animals but didn't participate in the new work, called the paper exciting.

It's the first formal study of how chimps and other apes respond to tickling, a highly detailed examination that compares an unusually wide range of species to humans, he said.

Panksepp's own work concludes that even rats produce a version of laughter in response to play and tickling, with chirps too high-pitched for people to hear. So he believes laughter goes even farther back in the mammalian family tree than the new paper proposes.

Robert Provine, a neuroscientist at the University of Maryland, Baltimore County, who wrote the 2000 book, "Laughter: A Scientific Investigation," said the new paper reveals some important insights, like details of the ape sounds that hadn't been appreciated before.
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Ancient Humans Knew Sustainable Fishing

Ancient Humans Knew Sustainable Fishing
Michael Reilly, Discovery News


June 1, 2009 -- Early humans living off the coast of California may
have been the first "farmers" of the sea.


By managing sea otter populations they maximized their harvest of
abalone and mussels, making them pioneers in the art of sustainable
fishery management, according to a new study.


Jon Erlandson of the University of Oregon and team of researchers
collected thousands of shells from ancient settlements of the Chumash
people in the Channels Islands near Santa Barbara, Calif., dating back
to around 12,000 years ago.


They found that while people were harvesting millions of shellfish
annually from the local kelp forest ecosystem, shell sizes remained
relatively stable even as the local population grew and became more
technologically advanced.


The trend suggests Channel Island settlers may have been the first to
work out a sustainable form of fishing. When certain areas became
depleted, they simply moved to another, effectively imposing a "no-
take zone" in the old fishing grounds. And when harvests dwindled
throughout the region, they switched to hunting and eating otters
until shellfish numbers recovered.


In previous studies, researchers have documented human impacts on
shellfish populations in the Mediterranean Sea as long as 25,000 years
ago. And evidence from South Africa suggests humans were hunting the
seas up to 120,000 years ago.


"For most of the 20th century, we thought any intensive use of marine
resources was limited to the last 10,000 years, the same time as the
agricultural revolution," Jon Erlandson of the University of Oregon
said. "But you have to understand that humans have been messing with
Mother Nature for a long time."


Erlandson presented his findings last week at the Oceans Past 1/
conference in Vancouver, British Columbia.


Daniel Pauly of the University of British Columbia argues the shells
are signs of opportunism, not management.


"Management implies you do something intentionally, you have a plan, a
goal," he said. "I think these people had a strategy to exploit
resources, and when it had a bad result, they switched from shellfish
to otters."


Still, Pauly said the work could teach us a valuable lesson about
managing modern day fisheries. About one-third of the global fish
catch goes to feeding farmed animals like pigs, chickens, salmon and
tuna. And it takes about four kilograms (8.8 pounds) of smaller fish
like sardines or anchovies, to produce one kilogram (2.2 pounds) of
tuna or pork.


Just by eating those smaller fish, Pauly said we might greatly reduce
pressure on global fisheries.
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Wednesday, June 3, 2009

David Eddings Is Dead

David Eddings Is Dead
Wednesday June 3, 2009

David Eddings
© Ballantine Books
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Beloved and influential fantasy author David Eddings, who in tandem with his late wife Leigh managed to garner both commercial and critical success with several series of best-selling novels, has passed away at the age of 77.

Eddings is best known for The Belgariad series, the first installment of which, The Pawn of Prophecy (1982), prompted Lester del Rey to tell him, "You've written a classic." The series introduced many to fantasy, and inspired some to write themselves (including Stephen Hunt, whose tribute to Eddings is here). Eddings was himself inspired by the success of The Lord of the Rings, which he was startled to discover was in its 78th printing when he encountered a display copy in a bookstore.

The Eddings' work includes The Belgariad series (5 books, 1982-1984) and The Malloreon series (5 books, 1987-1991), with three related books in the 1990s; The Elenium and The Tamuli (two trilogies, 1989-1994); and The Dreamers series (4 books, 2003-2006).

Eddings was famously old-fashioned, never using a typewriter or computer (he wrote out his scripts in long-hand) and was well-known for being self-effacing, once remarking, "I'm never going to be in danger of getting a Nobel Prize for literature." He was most pleased when told that his books had turned nonreaders into booklovers. "I look upon this as perhaps my purpose in life," he explained in a 1997 interview. "I am here to teach a generation or two how to read. After they've finished with me and I don't challenge them any more, they can move on to somebody important like Homer or Milton."

When asked in a recent interview what made his books so successful, Eddings replied with the same answer many of his fans would give: "Characters. My people are as real as I can make them." Source
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Cantabrian cornice has experienced seven cooling and warming phases

Cantabrian cornice has experienced seven cooling and warming phases
over past 41,000 years


03 June 2009 Plataforma SINC


The examination of the fossil remains of rodents and insectivores from
deposits in the cave of El Mirón, Cantabria, has made it possible to
determine the climatic conditions of this region between the late
Pleistocene and the present day. In total, researchers have pinpointed
seven periods of climatic change, with glacial cold dominating during
some of them, and heat in others.


In 1996, an international team of scientists led by the University of
Zaragoza (UNIZAR) started to carry out a paleontological survey in the
cave of El Mirón. Since then they have focused on analysing the fossil
remains of the bones and teeth of small vertebrates that lived in the
Cantabrian region over the past 41,000 years, at the end of the
Quaternary. The richness, great diversity and good conservation status
of the fossils have enabled the researchers to carry out a
paleoclimatic study, which has been published recently in the Journal
of Archaeological Science.


"We carried out every kind of statistical analysis over a six-month
period at the University of New Mexico, analysing around 100,000
remains, of which 4,000 were specifically identified, and catalogued
according to species and the number of individuals in each stratum",
Gloria Cuenca-Bescós, lead author of the study and a researcher in the
Paleontology Department of the UNIZAR's Institute for Scientific
Research (IUCA), tells SINC.


The resulting study involves climatic inferences being drawn on the
basis of the fossil associations of small mammals whose remains have
been deposited in El Mirón over the past 41,000 years. The fossil
associations of these mammals reveal the composition of fauna living
around the cave at the time, and have made it possible to develop a
paleoclimatological and paleoenvironmental reconstruction of the
environment.


The research shows that there have been seven periods of cooling and
warming in the Cantabrian cornice over the past 41,000 years. An
analysis carried out by other authors on data relating to pollen,
marine isotope stratigraphy, and materials deposited by glaciers backs
this up this result.


The water rat was king of the Late Pleistocene


According to the study, there were four unstable cold periods, two
more stable ones, and a temperate climatic period at the El Mirón
cave. The scientists are unsure about dating the seventh and last
period ended, as this "could correspond with the Bronze Age, the Ice
Age, or the start of agricultural expansion by human beings, which
certainly would have impacted on the wild animals living close to the
caves.


However, the study shows that during earlier periods at the end of the
Late Pleistocene, the species that predominated during cold periods
were rodents and insectivores that were well-adapted to environments
with only sparse vegetation. "When climatic conditions became more
mild at the end of the last cold pulse of the Late Pleistocene, known
as the Dryas III, forest-dwelling rodents and insectivores flourished
and become more frequent in the associations", explains Cuenca-Bescós.
We now know that the water vole (Arvicola terrestris) dominated in
this period.


According to the researcher, this domination by woodland species
started to decline in the area only at the end of the Holocene, when
human activities began to change the landscape, and when deforestation
resulting from permanent settlements and agriculture can be observed
"even though the climate continued to be favourable to these kinds of
organisms".


The study has also shown that the majority of the Pleistocene taxa
became extinct around 10,000 years ago while "some cold-adapted
species, which had managed to survive, moved to the north of Europe,
leaving our warmer latitudes behind", the scientist concludes.

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Tuesday, June 2, 2009

'Oldest pottery' found in China

Examples of pottery found in a cave at Yuchanyan in China's Hunan province may be the oldest known to science.

By determining the fraction of a type, or isotope, of carbon in bone fragments and charcoal, the specimens were found to be 17,500 to 18,300 years old.

The authors say that the ages are more precise than previous efforts because a series of more than 40 radiocarbon-dated samples support the estimate.

The work is reported in the Proceedings of the National Academy of Sciences.

The Yuchanyan cave was the site where the oldest kernels of rice were found in 2005, and it is viewed as an important link between cave-dwelling hunter-gatherer peoples and the farmers that arose later in the basin of the nearby Yangtze River.

Archaeologists before haven't looked at this closely enough to realise what's going on in caves

David Cohen
Boston University
The previous oldest-known example of pottery was found in Japan, dated to an age between 16,000 and 17,000 years ago, but debate has raged in the archaeological community as to whether pottery was first made in China or Japan.

The most recent dig at Yuchanyan was in 2005 by a team led by Elisabetta Boaretto of the Kimmel Center for Archaeological Science at the Weizmann Institute of Science in Israel. They believe they have found a more precise way to read the history of human activity written in layers of sediment, or stratigraphy.

'Layer cake'

"The way people move around and mess up caves is very difficult to see archaeologically," David Cohen, an archaeologist at Boston University and a co-author on the research, told BBC News.

"Imagine you have a fire and then people come in again have another fire and another, so you have the ashes of all these fires building up but at the same time people are digging and clearing, pushing things to the side; this messes things up.


Fragments from a 1995 dig at Yuchanyan form a cauldron
"If you have an open-air site, you sometimes get a very clean 'layer cake' stratigraphy. Archaeologists before haven't looked at this closely enough to realise what's going on in caves so they interpret this stratigraphy as a layer cake. But in actuality, it's 'lenses' of stuff that's been mixed up and moved around."

It is comparatively easy to find evidence of human occupation in caves through the dating of charcoal from fires or bones from long-ago dinners, Dr Cohen said. However, because of the unclear layering of sediment it is not easy to correlate well-dated layers with the pottery that may be nearby.

Part of the problem lies in the areas over which previous digs have searched: squares of perhaps five metres on a side.

"It's an issue of association, knowing where everything comes from in space across the cave," Dr Cohen explained. "If you're excavating in a huge unit, you can only say it comes from within this 5m area and this 20cm of sediment, and that's not good enough for understanding human activity."

Instead, the team worked in sub-divisions of just a quarter of a metre square, painstakingly collecting bone and charcoal fragments. The samples were then radiocarbon dated, revealing a clean distribution stretching between 14,000 and 21,000 years ago.

'Fantastic cave'

One fragment of pottery was found in a layer between two radiocarbon-dated fragments that both measured about 18,000 years old, taking the record for oldest pottery.

The team hope that their smaller-scale searching and taking into account the effects of human activity on cave stratigraphy will help with future digs at Yuchanyan, and elsewhere.

"It's a fantastic cave, and we hope that the way these excavations were done would set a precedent for how other caves will be looked at," said Dr Cohen.

Dr Tracey Lu, from an anthropologist at the Chinese University of Hong Kong, who was not an author on the latest study, noted that the dates reported in this paper were slightly older than dates on pottery found in Japan.

However, she said the accuracy of radiocarbon dates in the limestone area has been under debate for many years.

"I agree that pottery was made by foragers in South China," she told the Associated Press news agency.

"But I also think pottery was produced more or less contemporaneously in several places in East Asia... from Russia, Japan to North and South China by foragers living in different environments."
The BBC Story
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