kutschera 14c session megiddo - tau...megiddo, israel, 20-22 june2010 general introductionto...
TRANSCRIPT
Radiocarbon dating
Elisabetta Boaretto
Radiocarbon Dating and Cosmogenic Isotopes Laboratory
The Martin (Szusz) Department of Land of Israel Studies and Archaeology
Bar Ilan University
and
Kimmel Center for Archaeological Science
Weizmann Institute of Science
Walter KutscheraVienna Environmental Research Accelerator (VERA) Laboratory
Faculty of Physics – Isotope Research
University of Vienna
Synchronizing Clocks at ArmageddonWorkshop on Archaeological Dating
Megiddo, Israel, 20-22 June 2010
General Introduction to Radiocarbon
Standard Radiocarbon Dating
14Ct = 14CO e-λλλλt
t = 1/λλλλ x ln(14CO/ 14Ct)
t = t1 /2 /ln2 x ln(14CO/ 14Ct)
Conditions:
• 14CO must be known for all times. Because material of known age
(tree rings) is available back to about 12,500 years B.P., 14CO is well
calibrated for this period. Beyond this, the calibration has larger
uncertainties, but does exist now back to 50,000 years.
[Reimer et al., INTCAL09, Radiocarbon, 51/4 (2009) 1111-1150]
• t1 /2 need not to be known accurately, because the14C determination
– the uncalibrated, so-called ‘radiocarbon age‘ – is performed with
exactly the same procedure in unknown samples as in the tree-ring samples. The latter delivers the translation of the uncalibrated
radiocarbon age into a calendar date.
Absolute Radiocarbon Dating14Ct →→→→ 14N* + e- + ννννe
Total energy release: 156 keV
Maximum recoil energy of 14N*: 7.3 eV
_________________________________
14Ct = 14CO e-λλλλt = (14Ct + 14N* ) e-λλλλt
t = 1/λλλλ x ln(1 + 14N*/14Ct)
t = t1/2/ln2 x ln(1 + 14N*/14Ct)
Conditions:
• 14Ct and 14N* must be measured
• t1/2 must be accurately known
• 14CO need not to be known
12C12C 14C
12C 12C
12C
12C12C 14N*
12C 12C
12C
Benzene Pyridine
Change of chemical compound by in-situ decay of 14C
Reference: “An attempt at absolute 14C dating“, Jacob Szabo and
Israel Carmi (Weizmann Institute), Dror Segal and Eugenia Mintz
(Israel Antiquities Authority), Radiocarbon 40/1 (1998) 77-83.
O3 + hνννν →→→→ O2 + O(1D)
O(1D) + H2O →→→→ 2OH•
OH•/O2 ~ 10-13!
12,000 10,000 7500 5000 2500 0
Years before present
Reference value: 14C/12C = 1.2x10-12
Subfossil pine out of a gravel pit near Tapfheim, Danube river, grown11,200 years before present (BP).(B. Kromer, Universityof Heidelberg)
Natural 14C variations
14C Bomb Peak
Variation of the 14C content in atmospheric CO2
during the last 4000 Years
Long-term observations of ∆∆∆∆14C in atmospheric CO2
in the northern and in the southern hemisphereLevin and Hesshaimer, Univ. Heidelberg, Radiocarbon 42/1 (2000) 69
Natural 14C level
NTBT 1963
14C decay (t1/2 = 5740 a)
The Iceman “Ötzi“ two days after his discovery (Sept. 1991), emerging from an ice patch at 3120 m a.s.l. in the Ötztal Alps at the Austrian/Italian border
Bow
14C dating of bone and tissuefrom the Iceman Ötzi at theAMS labs of Oxford and Zürich in 1992
Uncalibrated (radiocarbon) age:4550 ± 19 yr BP (before present)
Calibrated age range:5300 to 5050 BP
Direct dating of Early Upper Paleolithic human remains from the Mladeč Caves in Moravia (Czech Republic)
Eva Maria Wild et al., Nature 435 (2005) 322
Sampled areas for 14C measurements at VERA
Radiocarbon ages determined for the human remains from the Mladeč site in Moravia (Czech Republic)
_____________________________________________________________________________
Lab Number Sample Name Sample material 14C-age(years BP)
_____________________________________________________________________________
VERA-2736 Mladeč 25c Ulna 26,330 ± 170
VERA-3073 Mladeč 1 Right molar M2 31,190 ± 400distal half of the crown
VERA-3074 Mladeč 2 Left molar M3 31,320 ± 400distal half of the crown
VERA-3075 Mladeč 8 Left molar M2 30,680 ± 380mesial-buccal root
VERA-3076A Mladeč 9a Right maxillary canine, Lingual half 31,500 ± 410of the root (white-coloured collagen)
VERA-3076B Mladeč 9a Right maxillary canine, Lingual half 27,370 ± 230of the root (brown-coulored collagen)
_____________________________________________________________________________
Radiocarbon calibration from 23,000 to 47,000 years BP (before present)E. Bard et al., A Better Radiocarbon Clock, Science 303 (2004) 178
Radiocarbon-Based Chronology for Dynastic Egypt
C. Bronk Ramsey, M. W. Dee, J. M. Rowland, T. F. G. Higham, F. Brock
Research Laboratory for Archaeology and the History of Art, University of Oxford, UK
S. A. Harris
Department of Plant Sciences, University of Oxford, UK
A. Quiles
Laboratoire de Mesure du Carbone 14, CEA, Saclay, France
E. M. Wild
Vienna Environmental Research Accelerator, University of Vienna, Austria
E. S. Marcus
The Recanati Institute for Maritime Studies, University of Haifa, Israel
A. J. Shortland
Centre for Archaeological and Forensic Analysis, Cranfield University, UK
SCIENCE, 328 (18 June 2010) 1554-1557
Comparison of Pharao accession dates from the Historical Chronology of Egypt(marked in red, blue and green) for the Old Kingdom (A), the Middle Kingdom (B)
and the New Kingdom with sequenced radiocarbon dates.
Distribution of uncalibrated radiocarbon dates against the modeled age,together with the calibration curve. Outliers are indicated in light gray.Total of 211 14C measurements, 188 accepted (23 outliers).
Investigating the likelihood of a reservoir offset in theradiocarbon record for ancient Egypt
M. W. Dee, F. Brock, C. Bronk Ramsey, T. F. G. Higham, J. M. Rowland,
Research Laboratory for Archaeology and the History of Art, University of Oxford, UK
S. A. Harris
Department of Plant Sciences, University of Oxford, UK
A. J. Shortland
Centre for Archaeological and Forensic Analysis, Cranfield University, UK
AMS radiocarbon measurements were made on 66 known-age samples of
short-lived plant species collected in Egypt between 1700 and 1900 AD.
Journal of Archaeological Science, 37 (2010) 687-693
Comparison between yearly averages and calibration curve values. An average offset of 19 ± 5 years was obtained.
Investigating the likelyhood of a reservoir offset in the radiocarbon record for ancient Egypt, Dee et al., J. Archaeol. Sci 37 (2009) 687-693
14C AMS measurements at Oxford of 66 short-
lived plants grown in Egypt between 1702 and
1881 resulted in an offset of 19 ± 5 years.
Regional offset in radiocarbon dates from the calibration curve(A) Modeled result (dark gray) with input of offset = 19 ± 5 yr (light gray)
(B) Modeled result (dark gray) with no input offset = 0 ± 10 yr (light gray)
A brief introduction to VERA,
the Vienna Environmental Research Accelerator
WIEN___________0.5 km
VERA
1.5 km
VERA 1993
Währinger Straße 17
Wolfgang AmadeusMozart composedhere Cosi fan tutte
in 1790
VERA 1993
Wolfgang AmadeusMozart composedhere Cosi fan tutte
in 1790
Ludwig van Beethovendied here in 1827
VERA 1993
Wolfgang AmadeusMozart composedhere Cosi fan tutte
in 1790
Ludwig van Beethovendied here in 1827
VERA 1993
800 m to birth place of
Franz Schubert, 1799
Wolfgang AmadeusMozart composedhere Cosi fan tutte
in 1790
Ludwig van Beethovendied here in 1827
500 m down this road,
Sigmund Freud livedfrom 1891 to 1938
VERA 1993
800 m to birth place of
Franz Schubert, 1799
Wolfgang AmadeusMozart composedhere Cosi fan tutte
in 1790
Ludwig van Beethovendied here in 1827
500 m down this road,
Sigmund Freud livedfrom 1891 to 1938
VERA 1993
Victor Hess discoveredCosmic radiation in 1912
800 m to birth place of
Franz Schubert, 1799
Primary cosmic ray (proton)
Victor HessBaloon flights
in 1912 up to 5000 m
Victor F. Hess shared the 1936 Nobel Prize in Physics (for thediscovery of cosmic rays) withCarl D. Anderson (for thediscovery of the positron)
Willard F. Libby (1905-1980)
1960 Nobel Prize in Chemistry
“for his method to use carbon-14
for age determination in
archaeology, geology, geophysics,
and other branches of science“
Photo by Fabian Bachrach circa 1952
12 April 2007
14Co
14Ct = 14Co e-λλλλt
Age determination by radiocarbon content: checks with samples of known age
James R. Arnold and Willard F. Libby, Science 110 (1949) 678-680
Isotope abundances of some light elements
Hydrogen 1H 99.985 %2H(D) 0.015 %
Carbon 12C 98.900 %
13C 1.100 %
14C 0.000 000 000 1 % (t1/2 = 5 730 a)
Nitrogen 14N 99.634 %15N 0.366 %
Oxygen 16O 99.762 %17O 0.038 %18O 0.200 %
6 6
6 7
6 8
Typical sample size:1 mg Carbon
5x1019 12C atoms
6x1017 13C atoms
6x107 14C atoms
1 14C decay/hour (liquid scintillation counting)
106 14C atoms/hour (atom counting with AMS)
Determination of the 14C content in carbon( 14C/12C = 1.2x10-12 )
Accelerator Mass Spectrometry (AMS) for “all“ isotopes: 10Be, 14C, 26Al, 36Cl, 41Ca, 55Fe, 129I,182Hf, 210Pb, 210Bi, 236U, 293-244Pu, SHE, (H2)
–, (43Ca19F4)– –, PIXE-ART, Nucl. reactions: 6,7Li
Negative-Ion Sources
Negative-Ion MassSpectro-meter(keV)
Positive-Ion MassSpectro-Meter(MeV)
Stripping and Molecule Dissociation
Detector area
1996: 1st operation2001: 1st upgrade2007: 2nd upgrade
Essentially all AMS facilities use negative ions
Isotope Abundance
12C– 98.9 %
13C– 1.1 %14C– 0.000 000 000 1 %12CH2
– ~0.1%13CH– ~0.001%14N– 0 !
Kavalierstrakt
Paul Damon, Univ. of Arizona Pioneer in 14C dating
V E R AVienna Environmental
Research Accelerator
wallsremoved
entrance foraccelerator
Positioning of the 3-MV Pelletron tandem accelerator from NEC in the“Kavalierstrakt“, Währingerstr. 17, A-1090 Wien (1995)
Column structure of the 3-MV tandem accelerator of VERA
Peter Steier
Robin Golser
Eva Maria Wild
Alfred Priller
Vienna EnvironmentalResearch Accelerator
(3-Million Volt Tandem)
KAVALIERSTRAKT
First Floor
Sample Preparation
Sample preparation for 14C measurements
1. Pretreatment
ultrasinic bath (removal of adherent particles)
ABA (acid-base-acid; removal of carbonates, humic acid)
“crude gelatine“ (collagen extraction from bone)
2. Combustion to CO2
sample (~10 mg) + CuO →→→→ (900 °C) →→→→ CO2 + H2O, N2,...
3. Catalytic “graphitization to elemental carbon
CO2 + 2H2 →→→→ (Fe, 580 °C) →→→→ C + H2O
4. Target pressing
iron-carbon mixture (~1 mg) is pressed into aluminum
target holders of the Cs-beam sputter ion source
Ion source
(MC-SNICS, NEC)
The Cesium-Beam Sputter Source for Negative Ionsas developed by the late Roy Middleton in the 1980s
at the University of Pennsylvania
Cesium Vapor
Acceleration Region
Carbon Target
50 µA 12C‾Cs+
400 14C‾/s
hot surface~ 1000 °C
The World of VERA
Staff of VERA
Eva Maria WildVice Head of Isotope Research
Group, Head of 14C dating, sample
preparation and stable isotope lab
Research interests
Archaeology (14C), paleodiet (δ13C, δ 15N), paleoclimate (10Be, 26Al)
Robin GolserHead of Isotope Research
Group
Research interests
Atomic physics (exotic ions),
ion beam analysis (PIXE
and PIGE)
Alfred PrillerTechnical Head of VERA
Research interests:
Accelerator development
(ion source, injector),
loess and paleoclimate
(10Be)
Peter SteierHead of VERA Operation
Research interests:
Glacier dating (14C),
DNA dating (14C),
environmental physics
(36Cl, 236U, 244Pu)
Anton Wallner
Research interest
Nuclear physics (fusion: 26Al, 53Mn), nuclear astrophysics
(supernova remnants: 244Pu;
stellar nucleosynthesis: 10Be, 14C, 26Al, 36Cl, 41Ca, 55Fe,
210mBi, 236U)
Oliver Forstner
Research interests
Instrumentation, detector
development, laser
interaction with negative
ions (HfFn–)
Radiocarbon dating of the Santorini eruption
Black Sea
Mediterranean Sea CreteCyprus
Nile Delta
Anatolia
Santorini
Tell el-Daba
Palestine
Cairo
Luxor
(West Thebes)
Greece
Santorini Eruption Radiocarbon Dated to 1627-1600 BC
W. L. Friedrich, T. Pfeiffer
Department of Earth Sciences, University of Aarhus, Denmark
B. Kromer, S. Talamo
Heidelberger Akademie der Wissenschaften und Institut für Umweltphysik
Universität Heidelberg, Germany
M. Friedrich
Institut für Botanik, Universität Hohenheim, Germany
J. Heinemeier
Accelerator Mass Spectrometry 14C Dating Centre
Department of Physics and Astronomy, University of Aarhus, Denmark
Science 312 (28 April 2006) 548
TreeTree
Minoan Pumice
Tom Pfeiffer
Olive branch in pumice
Pumice section on Santorini
(Thera) showing the location of
the olive tree branch (lowermost
hole) and the presumed position
of the tree (ghosted)
Walter Friedrich
Olive tree branch
X-ray tomography, cross section
of the olive tree branch
X-rayimage
1750 1700 1650 1600 1550 15003150
3200
3250
3300
3350
3400
3450
3500
Outermost ring set to 1525
Santorini Olive
14C
age B
P
cal BC
-150 -100 -50 0 50
3150
3200
3250
3300
3350
3400
3450
3500
Santorini
German oak Heidelberg
Age of the outermosttree ring:
1613 ± 13 yr BC
Chronology for the Aegean Late Bronze Age
1700 – 1400 BC
S. W. Manning
Department of Classics, Cornell University, Ithaca, NY, USA and
Department of Archaeology, School of Human and Environmental Sciences
University of Reading, UK
C. Bronk Ramsey, T. Higham
Oxford Radiocarbon Accelerator Unit, Research Laboratory for Archaeology
and the History of Art, Oxford University, UK
W. Kutschera, P. Steier, E. M. WildVienna Environmental Research Accelerator (VERA) Laboratory
Institut für Isotopenforschung und Kernphysik, Universität Wien, Austria
B. Kromer
Heidelberger Akademie der Wissenschaften und Institut für Umweltphysik
Universität Heidelberg, Germany
Science 312 (28 April 2006) 565-569
127 14C dates from these sites were measured and analysed with the Bayesian method
Schematic representation of the Aegean early Late Bronze Age
archaeological chronology derived from 127 high-precision 14C measurements
Average of 28 short-livedsamples from the TheraVolcanic Destruction Layer(VDL)
Acrotiri (1660-1612 BC)
Average of 28 short-livedsamples from the TheraVolcanic Destruction Layer(VDL)
Acrotiri (1660-1612 BC) Olive tree (1627-1600 BC)
Tell el-Daba in the Nile Delta
Tell el-Daba
Tell el-Daba excavation area
Manfred Bietak“King“ of
Tell el-Daba
1868 BC 1540 BC
(2006): 5 1 3 2 4 2 2 1 4 6 6 1 2 1
Stele
(Sesostris III)
Destruction layer
(Ahmose I)
TheraPumice
White slip wareand Minoan-style paintingThera
eruption
S. W. Manning et al., C14 – VDL date, Science 312 (2006) 565W. L. Friedrich et al., C14 - Olive tree, Science 312 (2006) 548
Middle Kingdom Second IntermediatePperiodHyksos
Samples per phase: 5 1 3 2 4 2 2 1 4 6 6 1 2 1
Short-lived plant material (seeds) was selected for 14C measurements
Middle Kingdom Second Intermediate PeriodHyksos
Comparison of 14C dates (calibrated 2-sigma ranges) with the historicalchronology of Egypt linked through the stratigraphy of Tell el-Daba phases
Middle Kingdom Second intermediate periodHyksos
Comparison of 14C dates (calibrated 2-sigma ranges) including 5 splits of samples measured at the Oxford AMS Lab with the historical chronology of
Egypt linked through the stratigraphy of Tell el-Daba phases
Middle Kingdom Second Intermediate PeriodHyksos
Comparison of 14C dates (2-sigma ranges after Bayesian sequencing)with the historical chronology of Egypt linked through
the stratigraphy of Tell el-Daba phases
Middle Kingdom Second Intermediate PeriodHyksos
Comparison of 14C dates (2-sigma ranges after Bayesian sequencing)with the historical chronology of Egypt linked through
the stratigraphy of Tell el-Daba phases
~120 year shift
Middle Kingdom Second Intermediate PeriodHyksos
Chronology of Dynastic Egypt and the Santorini eruptionFrom: Hendrik J. Bruins, Science 328, 1489, 18-June-2010
“It is better to be roughly right
than precisely wrong.“
- Einstein