SETI bioastro: Fw: Cornell News: The Sun, tree rings and history

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From: LARRY KLAES (ljk4@msn.com)
Date: Sat Dec 22 2001 - 18:18:09 PST


----- Original Message -----
From: cunews@cornell.edu
Sent: Thursday, December 20, 2001 3:39 AM
To: CUNEWS-PHYSICAL_SCIENCE-L@cornell.edu; CUNEWS-SOCIAL_SCIENCE-L@cornell.edu; CUNEWS-SCIENCE-L@cornell.edu
Subject: Cornell News: The Sun, tree rings and history

Archaeologists rewrite timeline of Bronze and Iron Ages, including
early appearance of alphabet

FOR RELEASE: Dec. 19, 2001

Contact: Blaine P. Friedlander Jr.
Office: 607-255-3290
E-mail: bpf2@cornell.edu

ITHACA, N.Y. -- Using information gleaned from the sun's solar cycles
and tree rings, archaeologists are rewriting the timeline of the
Bronze and Iron Ages. The research dates certain artifacts of the
ancient eastern Mediterranean decades earlier than previously
thought. And it places an early appearance of the alphabet outside
Phoenicia at around 740 B.C.

Writing in two articles in the forthcoming issue of the journal
Science (Dec. 21), archaeologists from Cornell University and the
University of Reading (England) and a physicist from
Ruprecht-Karls-Universität Heidelberg (Germany) have given a new
kind of precision to the timeline of the Bronze and Iron Ages in the
Aegean and the Near East.

"Establishing this chronology means that the objects -- metalwork,
furniture, woven textiles, and an alphabetic inscription found in a
tomb in central Turkey -- were older than previously thought by some
22 years," said Peter I. Kuniholm, Cornell professor of art history
and archaeology.

Among the artifacts found in the Midas Mound Tumulus at Gordion, the
capital of ancient Phrygia, a site west of Ankara, Turkey, is a
shallow, bronze bowl with a patch of beeswax on the rim carrying an
alphabetical inscription. The inscription is a precursor to -- or
contemporary with -- the earliest attested occurrences of the Greek
alphabet. In addition to letter forms known from ancient Greek,
there is a vertical arrow, known also from Etruscan inscriptions.

With the new chronology, the bowl now is independently dated circa
740 B.C., making its inscription as old as the oldest known artifacts
on which the Greek alphabet appears: an oinochoe (a wine pitcher)
from the Dipylon cemetery in Athens and a cup from Pithekoussai (now
Ischia) in the Bay of Naples. The estimated dates of these pots
previously had provided archaeologists with only an approximate date
for these early alphabetic inscriptions. "The alphabet, which
originated in Phoenicia at a time that is still disputed, was moving
west at a rapid pace, traditionally thought to be by sea but now
clearly by land as well. That's what this chronology shows: The
alphabet was really catching on," says Kuniholm. Scholars believe
that the birthplace of all Western alphabets, including the Greek and
Roman, was Phoenicia (present-day Lebanon, Israel and Palestine). The
oldest known Phoenician inscription was found in the Ahiram epitaph
at Byblos, Lebanon, dating from about the 11th century B.C. Scholars
think the alphabet was spread throughout the Mediterranean by traders
who found the new shorthand an improvement over the syllabic scripts
such as Linear B and cuneiform Hittite.

Kuniholm and his colleagues are using the science of both carbon
dating and dendrochronology, dating through tree rings, to calibrate
history. Their latest research involved carbon-14 analysis on
10-year slices -- that is rings covering 10 years of growth -- on
wood from pine trees from the Catacik Forest in Turkey and from oak
trees in Germany. By currently accepted models, the carbon-14
concentrations should have been identical in both the pine and the
oak. And while the scientists discovered that this was true in
general, they were surprised to find that for certain key periods,
the Turkish pine appeared to be older than the German oak by as much
as 17 years. "Those pieces of wood are the same tree-ring age, and
they should have the same radiocarbon age, but they don't," says
Kuniholm.

What happened, Kuniholm believes, is that the Turkish pine, growing
in a warmer climate and at a lower latitude, absorbed less carbon-14
during documented periods of so-called solar minima -- prolonged
cooling periods in the Northern Hemisphere, such as those in the
eighth and ninth centuries B.C. and in the 15th and 16th centuries
A.D. The German oak, which starts its growing season later in the
spring than does the Turkish pine, absorbed measurably more amounts
of carbon-14 during such cooling periods. "The trees are like a tape
recorder of the radioactivity of the cosmos," Kuniholm said, "but
they record only when they are growing."

Carbon-14, an isotope of the element carbon, is produced in the
Earth's lower stratosphere by the collision of neutrons, produced by
cosmic rays, with nitrogen. (An isotope is made up of atoms of the
same element but with different numbers of neutrons.) During periods
of high solar activity, the solar wind prevents charged particles
from entering the atmosphere -- thus producing little carbon-14.
However, carbon-14 production peaks during the solar minima, and it
enters the Earth's troposphere as carbon dioxide-14 during the late
spring in the Northern Hemisphere. By the following spring, the
higher concentration of carbon in the troposphere is diluted. Thus,
German oak, which grows late in the spring and summer, absorbs less
carbon dioxide-14 than Turkish pine or juniper, which grows from the
early spring to summer. "This is the first time scientists have been
able to note a regional difference in tree rings of the same
dendrochronological age," says Kuniholm. "Sadly, now, with all the
carbon in our atmosphere, with the pollution we have from our cars
and factories and energy facilities, the trees have all but given up
providing many of these valuable signals."

Kuniholm's co-authors on the Science papers were Sturt Manning of the
University of Reading, Bernd Kromer of
Ruprecht-Karls-Universität Heidelberg, and Maryanne Newton,
Cornell doctoral candidate. Research collaborators also include Marco
Spurk, Universität Hohenheim, Stuttgart, Germany, and Ingeborg
Levin, Universität Heidelberg, Germany. The concurrent Science
articles are titled, "Regional Radioactive Carbon Dioxide Offsets in
the Troposphere: Magnitude, Mechanisms and Consequences" and
"Anatolian Tree Rings and a New Chronology for the East Mediterranean
Bronze-Iron Ages."

The research was funded by the Institute for Aegean Prehistory, the
National Science Foundation, the Malcolm H. Wiener Foundation, the
Heidelberg Academy of Sciences and Germany's Federal Ministry of
Educational Research.

Related World Wide Web sites: The following sites provide additional
information on this news release. Some might not be part of the
Cornell University community, and Cornell has no control over their
content or availability.

o Aegean Dendrochronology Project: <http://www.arts.cornell.edu/dendro>

o A companion opinion piece in Science by Paula Reimer,
Livermore Laboratories:

<http://www.calib.org/paula>

-30-

EDITORS: This news release is not embargoed.

The web version of this release may be found at
http://www.news.cornell.edu/releases/Dec01/Carbon-14.bpf.html

Cornell University News Service
Surge 3
Cornell University
Ithaca, NY 14853
607-255-4206
cunews@cornell.edu
http://www.news.cornell.edu


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