Applications of AMS There is a rich field of applications for AMS - - PowerPoint PPT Presentation

Applications of AMS

There is a rich field of applications for AMS due to the increased efficiency and accuracy of radiocarbon dating. It ranges from geology, hydrology,

• ceanology, climatology, and a wide

range of environmental applications to history and archaeology

Example 1: Frozen Ice Mummies

Tools and mummified body found in the Tyrolean Alps

Ötzi – the Iceman

Preservation of Ötzi

• The temperature of the glacier

at a height of 3200 m runs from 0° to -10° C with a maximum at

• 5° or -6° C.
• The humidity of the glacier

amounts up to 100%. Unique conditions for freezer like preservation Discovery came by lucky accident at unusual high temperatures, which melted the storage snow. Five days later the area was covered again with snow.

The Age of Ötzi

Ötzi is a unique discovery. The body material and material

• f iceman equipment was immediately radiocarbon dated.

AMS method was chosen because it required only miniscule body samples (≈1mg). AMS measurements were performed independently at five different AMS accelerator labs.

• 1. ETH, Zürich, Switzerland
• 2. University of Oxford, UK
• 3. Gif-sur-Yvette, France
• 4. University of Uppsala, Sweden
• 5. VERA, University of Wien, Austria

The combined un-calibrated radiocarbon age is 4546±17 y BP (BP: before present 1950) 2596±17 BC. Calibration is necessary to account for variations in atmospheric 14C concentration.

Tree Ring Calibration

Calibration curve from 4000 to 2000 BC

Intersection of un-calibrated radiocarbon age with tree ring calibration will show calibrated age of sample. Detail of calibration 3500-3000BC indicate three possible intersections due to the statistical uncertainty of ±17 years. Calibration Shows that Ötzi is about 650 years older than radiocarbon date.

The find may be dated

• 3350-3300 BC with 56%,
• 3210-3160 BC with 36%
• 3140-3160 BC with 8%

probability, respectively, taking into account statistical uncertainties of the various measurements as well as uncertainties associated with the tree ring calibration curve. Overall range of 250 years between 3100 an 3350 BC

Determination of Age

Average AMS dating Results

• f the Iceman

body & equipment

All materials show identical age range of 3100-3350BC

10000 years of transalpine trade

Results indicate that pass was used as transition route between the southern and northern slopes of the Alps at substantial earlier and later times 6000-1000BC.

Dating Results

• f other man-

related material found at the site

The Origin of Ötzi

• Both northern and

southern cultures possible.

• Pollen analysis of

the digested food indicates southern

• rigin.

Comparison with dates of known Neolithic alpine cultures

The Shroud of Turin

As many believe, the Shroud of Turin is the linen, which was used to wrap the body of Christ after crucification. The shroud shows an image (negative) of a man believed By many to be a mirror of the head and body of Jesus.

Gerard Davis, 15th century; The Deposition from the Cross; National Gallery, London

The Turin Shroud

The Image

Negative / Positive

On the left, is a photographic “negative image”, as it appears on the cloth itself. When photographed, a “positive” image emerges as the film is being developed. Claim is that negative resulted from chemical reactions between ammoniac evaporations from a tortured body (of Christ) and the cloth material.

The recorded History of the Shroud

In 1357, the Shroud is first mentioned, at Lirey, in the Champagne region of France. It was in the possession of Geoffrey de Charny, a French crusader, who claimed that he got it in Constantinople. Since that date the history of the Shroud is continuously known.

• From 1357 to 1418, at Lirey, Champagne, France.
• In 1532, a fire in the chapel of Chambery Castle, where the

Shroud was kept, damaged the Shroud.

• From 1418 to 1452, at Saint Hippolyte-sur-Doubs
• From 1452 to 1454, at Chambery
• From 1454 to 1578, it was on display at many locations.
• Since 1578, it has been kept at Turin in Italy.
• In 1997, fire broke out in the dome of Saint John the Baptist

Cathedral in Turin. The Shroud was not damaged in any way. The cloth measures 4.35 meters by 1.09 meters.

The believed History of the Shroud

Several theories exist, about the history of the Shroud before 1357. The most intriguing is that the Shroud is identical to the Mandylion. The main points in this account are :

• From 30 to 57: There are claims that a "portrait of Jesus" existed

in Edessa, on a cloth. It becomes known as the Mandylion.

• In 57, during Christian prosecution, the Mandylion disappeared.
• In 525, during reconstruction work, the Mandylion was found

hidden in the city wall.

• In August 944, the Mandylion arrives at Constantinople.
• Around 1025, a portrait is known that resembles the Holy Shroud.
• 12th April 1204, Crusaders sack the city of Constantinople,

and the Mandylion disappears.

• In 1357, the Shroud is on display at Lirey.

Travel Route of the Shroud

Mandylion Shroud Unrecorded claim

A detailed history of the shroud plus other information can be found at: http://www.shroud.com/history.htm

RELICS at the Mediaeval Ages

Relics developed such a major role in late antiquity

Dating the Shroud

The shroud was declared authentic by Pope Julius II in 1506.

A difficulty was the existence of several “medieval” shrouds at Besançan, Cadouin, Champiègne, Xabregas, who claimed to be of linen provided by Joseph of Arimathea for wrapping the body of Jesus after the crucification.

Radiocarbon dating was proposed in the 1960ies and 1970ies, But required too much material 500 cm2 (from 47415 cm2). 1987 AMS experiments were approved, and 1988/89 independent measurements were performed at three different AMS facilities.

• ETH, Zürich, Switzerland
• University of Oxford, UK
• University of Arizona, USA

Reminder about 14C Dating Method

Sample Requirements for AMS

AMS is a more suitable method, with 7 cm2 it needs two orders of magnitude less material, because you count the number of 14C atoms N in the sample rather than counting the number

• f decay processes A=λ·N (with λ being a small

Number λ=1.745·10-4 year-1) Samples were carefully removed from an edge

• f the shroud untouched by burning marks to

avoid possible contamination with more recent carbon (which would have a higher 14C content).

Preparation of the Sample

Experimental Procedure

Three ~50mg samples (Sample 1) were taken and distributed to the labs together with three different control samples. All for samples remained unidentified.

• Sample 2: Linen sample from a Nubian tomb

from the 11th to 12th century AD, ~ 950 years old

• Sample 3: Linen from an Egyptian mummy wrapping

from the early 2nd century AD, ~ 1900 years old

• Sample 3: Threads from a cope of St. Louis d’Anjou

from 1290-1310 AD, ~ 700 years old The labs split the samples into 3-5 probes and prepared the graphite pellets using different chemical preparation methods for the extraction of the carbon in form of C02.

For details see: Nature, Vol. 337, No. 6208, 1989, pp. 611-615

AMS Dating of the Shroud

Summary of Results

Sample 1 Age 1 Sample 2 Age 2 Sample 3 Age 3 Sample 4 Age 4 Pretreatment and replication codes Arizona AA-3367 AA-3368 AA-3369 AA-3370 A1.1b* 591±30 A2.1b 922±48 A3.1b 1,838±47 A4.1b 724±42 A1.2b 690±35 A2.2a 986±56 A3.2a(1) 2,041±43 A4.2a 778±88 a, method a A1.3a 606±41 A2.3a(1) 829±50 A3.3a 1,960±55 A4.3a(1) 764±45 b, method b A1.4a 701±33 A2.4a(2) 996±38 A3.4a(2) 1,983±37 A4.4a(2) 602±38 ( ), same subsample A2.5b 894±37 A3.5b 2,137±46 A4.5b 825±44 Ó13C (0/00)

• 25
• 23
• 23.6
• 25

Oxford 2575 2574 2576 2589 O1.1u 795±65 O2.1u 980±55 O3.1u 1,955±70 O4.2u 785±50 u, unbleached O1.2b 730±45 O2.1b 915±55 O3.1b 1,975±55 O4.2b(1) 710±40 b, bleached O1.1b 745±55 O2.2b** 925±45 O3.2b 1,990±50 O4.2b(2) 790±45 ( ), same pretreatment/ run combination Ó13C***(0/00)

• 27
• 27
• 27
• 27

Zurich ETH-3883 ETH-3884 ETH-3885**** ETH-3882 Z1.1u 733±61 Z2.1u 890±59 Z3.1u 1,984±50 Z4.1u 739±63 Z1.1w 722±56 Z2.1w 1,036±63 Z3.2w 1,886±48 Z4.1w 676±60 u, ultrasonic only Z1.1s 635±57 Z2.1s 923±47 Z3.2s 1,954±50 Z4.1s 760±66 w, weak Z1.2w 639±45 Z2.2w 980±50 Z4.2w 646±49 s, strong Z1.2s 679±51 Z2.2s 904±46 Z4.2s 660±46 Ó13C***** (0/00)

• 25.1
• 23.6
• 22
• 25.5

Each laboratory performed 3-5 independent measurements

Statistical Uncertainties

Sample 1 2 3 4 Arizona

646 ± 31 927 ± 32 1,995 ± 46 722 ± 43

Oxford

750 ± 30 940 ± 30 1,980 ± 35 755 ± 30

Zurich

676 ± 24 941 ± 23 1,940 ± 30 685 ± 34 Unweighted mean* 691 ± 31 936 ± 5 1,972 ±16 721 ± 20 Weighted mean** 689 ± 16 937 ± 16 1,964 ± 20 724 ± 20 X 2 value (2 d.f.) 6.4 0.1 1.3 2.4 Significance *** level (%) 5 90 50 30

While the Arizona and Zürich results are in statistical

• agreement. The Oxford results indicate a higher age.

Excellent agreement between the results of the three laboratories is obtained for all three test samples.

14C dating of the shroud

Sample 2: Linen sample from a Nubian tomb Sample 3: Linen from an Egyptian mummy wrapping Sample 3: Threads from a cope of St. Louis d’Anjou

610-780

Double peak in calibration curve

Final results

Sample Mean Date (yr BP) Calendar date ranges 1*

691 ± 31 68% AD 1273 - 1288 95% AD 1262 - 1312, 1353 - 1384 cal

2 **

937 ± 16 68% AD 1032 - 1048, 1089 - 1119, 1142 - 1154 cal 95% AD 1026 - 1160 cal

3**

1,964 ± 20*** 68% AD 11-64 cal 95% 9 cal BC - AD 78 cal

4**

724 ± 20 68% AD 1268 - 1278 cal 95% AD 1263 - 1283 cal

These results indicate a medieval forgery – typical for these times! Objections were raised on statistical grounds and on the grounds

• f the assumed fractionation values or 14C/12C-ratios

The Critics – Fire of 1532; Centuries of Exposure to Incense & Candles

• The shroud was exposed to high temperatures

above 300oC (burn marks, molten silver spots), ⇒ chemical fractionation between 14C and 12C can occur which would reduce the age.

• Incense and candle burning

in front of the shroud adds modern age contaminants with lower 14C abundance which would reduce age. The shroud would need a doubling of 14C abundance to obtain the required age.