SETI bioastro: FW: Cornell Chronicle: Tree rings rewrite history

From: LARRY KLAES (ljk4_at_msn.com)
Date: Thu Oct 25 2007 - 05:39:02 PDT

  • Next message: LARRY KLAES: "SETI bioastro: FW: CU-BOULDER: FIRST-KNOWN BELT OF MOONLETS IN SATURN RINGS"

    >From: Cornell Chronicle Online <cunews_at_cornell.edu>
    >Reply-To: Cornell Chronicle Online <cunews_at_cornell.edu>
    >To: CUNEWS-CAMPUS-L_at_cornell.edu
    >Subject: Cornell Chronicle: Tree rings rewrite history
    >Date: Wed, 24 Oct 2007 20:19:55 -0400
    >
    >Chronicle Online e-News
    >
    >How old trees and ancient wood are helping rewrite history explained by
    >tree-ring lab director
    >http://www.news.cornell.edu/stories/Oct07/ManningTrustees.kr.html
    >
    >Oct. 24, 2007
    >
    >By Krishna Ramanujan
    >ksr32_at_cornell.edu
    >
    >Cornell archaeologists are rewriting history with the help of tree rings
    >from 900-year-old trees, wood found on ancient buildings and through
    >analysis of the isotopes (especially radiocarbon dating) and chemistry they
    >can find in that wood.
    >
    >By collecting thousands of years worth of overlapping tree rings, with each
    >ring representing a tree's annual growth, the researchers have created
    >long-term records in the eastern Mediterranean that allow them to precisely
    >date such seminal milestones in history as when Hammurabi, "the law-giver,"
    >reigned, when the massive Santorini volcanic eruption occurred, and the
    >timelines of the Bronze and Iron ages, as well as many more recent events.
    >
    >Sturt Manning, director of the Malcolm and Carolyn Wiener Laboratory for
    >Aegean and Near Eastern Dendrochronology at Cornell, summarized his work
    >for Cornell council members and trustees, Oct. 19 in Statler Hall.
    >Dendrochronology is the science of comparing growth patterns in tree trunks
    >to date past events or climate changes. Cornell's dendrochronology
    >laboratory now holds more than 40,000 tree-ring samples, including many
    >from the eastern Mediterranean.
    >
    >Trees of the same species from the same geographical area have fairly
    >similar ring patterns, Manning said, because they are exposed to similar
    >climatic conditions. By starting with living trees and then finding samples
    >from slightly older trees used in buildings and still older trees from more
    >ancient sites, archaeologists have been able to overlap tree-ring data to
    >create chronologies that date back thousands of years.
    >
    >Radiocarbon dating, statistical analysis, researchers' trained eyes and
    >prior knowledge of events in the area are then used to match new samples
    >with tree-ring chronologies from the same area. Manning and his staff in
    >the lab have used such techniques to verify, for example, the likely
    >origins of a Circle of Rembrandt painting (referring to an elite group of
    >students that worked directly with the artist). He showed that the oak
    >board of the painting came from the same tree as the board of another
    >painting, whose origins are known and which hangs in a museum in Krakow,
    >Poland.
    >
    >Similarly, scholars have debated for more than 150 years about the dates of
    >the ancient civilizations of the Babylonians, the Assyrians and the
    >lifetime of Hammurabi, the Babylonian king who helped create the oldest set
    >of written laws. Mainstream scholars have proposed dates for his reign that
    >differ by 300 years.
    >
    >"You can't do history if you have a difference of 300 years or so," said
    >Manning. "That would place George Washington as a contemporary of some
    >person living right now. ... You'd get entirely the wrong historical
    >reconstruction if you didn't have the dates sorted out."
    >
    >Using ancient beams from palaces of known contemporaries of Hammurabi,
    >Cornell researchers combined radiocarbon dating techniques with
    >dendrochronological evidence to date Hammurabi to around 1792 B.C., Manning
    >said.
    >
    >Similar techniques used on wood buried beneath volcanic ash allowed Manning
    >and others to date the Santorini volcanic eruption, one of the largest in
    >the last 10,000 years, as most likely occurring in the late 17th century
    >B.C., 100 years earlier than previously believed. The discovery may rewrite
    >the late Bronze Age history of Mediterranean civilizations, he said.
    >
    >--
    >
    >
    >Chronicle Online
    >312 College Ave.
    >Ithaca, NY 14850
    >607.255.4206
    >cunews_at_cornell.edu
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    >
    >


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