The Radiocarbon Samples From The Acropolis Of Tel Yarmuth

CHAPITRE 23

 

THE RADIOCARBON SAMPLES

FROM THE ACROPOLIS OF TEL YARMUTH

 

Elisabetta BOARETTO

D-REAMS Radiocarbon Dating Laboratory

Weizmann Institute of Science, Rehovot

 

The Tel Yarmuth acropolis Sounding 2 was excavated during six seasons, exposing a

series of levels and contexts from which material was recovered for radiocarbon dating.

A total of ten samples were selected for final radiocarbon dating using either the decay

counting method or the accelerator mass spectrometry method. Under the supervision of

Dr Israel Carmi four samples were measured by decay counting (RT labelled samples in

Tables 23.1–23.2) in 1998 and six were measured by Prof. Elisabetta Boaretto by accelera-

tor mass spectrometry (AMS) with the D-REAMS accelerator (RTD labelled samples in

Tables 23.1 and 23.3) in 2013. All samples were measured at the Radiocarbon Laboratory

at the Weizmann Institute of Science (Israel).

 

23.1. THE SAMPLES

 

The samples were recovered from floors and from destruction events as identified during

the excavation. Samples were wood charred fragments or single seeds and were all botani-

cally identified by Nili Liphschitz.

The archaeological information of the radiocarbon dated samples, their botanical identi-

fication and expected age are shown in Table 23.1, in which they are ordered according to

the stratigraphic sequence, from the youngest (top) to the oldest (bottom).

All samples were pre-treated to remove all contamination. No information could be

recovered for the RT samples measured by decay counting beside the 14C age BP (Before

Present) and the stable isotope ratio δ13C. All the information about these samples are

reported in Table 23.2 together with the calibrated range for the ±1σ and ±2σ.

Samples labelled RTD were all short lived (seed or olive pit) and were prepared using the

Acid Base Acid pre-treatment procedure to remove all the contamination from the sample

prior to the radiocarbon dating. The samples were then prepared for the graphitisation and

finally measured by Accelerator Mass Spectrometry method at the D-REAMS radiocarbon

dating laboratory. The procedure for the sample preparation is reported in Yizhaq et al.

2005 and in Regev et al. 2017.

In 14 Table 23.3 , information about the samples’s context, material characteristic, C date

in year BP and the calibrated range for the ±1 σ and ±2σ are reported.

504 E. BOARETTO

 

The AMS samples (RTD label), although they were charred single seed or olive pit, pro-

vided enough material for the AMS measurement. The pre-treatment recovery of the sam-

ple or “efficiency percentage” (“Eff. %” in Table 23.3) was above 30% for all the samples

and the percentage of carbon after pre-treatment (“C %” in Table 23.3), was as high as

75% or higher. The high chemical efficiency and carbon percentage indicate a very good

state of preservation of the sample material.

Calibrated ranges were obtained using OxCal v4.3.2 Bronk Ramsey (2017) based on

Bronk Ramsey 2001 using the IntCal13 atmospheric curve in Reimer et al. 2013.

 

Lab # Basket No. Stratum Locus Type Context Date

expected (BCE)

RT-3029 9593 Acr-III 1130 Charcoal Destruction (beam) 11th cent.

RT-3030 9641 Acr-III 1149-1 Charcoal Destruction 11th cent.

RT-3031 9716 Acr-III 1171-2 Charcoal Destruction 11th cent.

RT-3032 10817 Acr-III 1149-1 Charcoal Mixed 11th cent.

RTD-6998 10888 Acr-III 1149-Floor a Olive pit OK : floor 11th cent.

RTD-6697 9649 Acr-III 1149-Floor b Olive pit OK : floor 11th cent.

RTD-6702 9653 Acr-IV 1150-Floor a Olive pit OK : floor End 12th cent.

RTD-6999 10621 Acr-V 1186-1 Seed OK Mid-12th cent.

RTD-6700 10659 Acr-V 1186-Floor a Olive pit OK : floor Mid-12th cent.

RTD-6701 10683 Acr-V 1186-Floor b Olive pit OK : floor Mid-12th cent.

 

Table 23.1. Archaeological context, botanical identification and expected age of the samples radio-carbon dated from Sounding 2 on the acropolis of Tel Yarmuth. The order follows the stratigraphic sequence. Samples labelled RT were measured by decay counting method; samples labelled RTD

were measured by accelerator mass spectrometry.

 

Lab # Field ID. δ13 14 C C age Calibrated range Calibrated range

(‰) year BP ± 1σ ± 2σ

Bask. No. 9593 1260 BC (45.1%) 1190 BC 1375 BC ( 2.1%) 1355 BC

RT-3029 L.1130 -22.2 2980 ± 35 1180 BC (12.8%) 1160 BC 1300 BC (92.8%) 1075 BC

Str. Acr-III 1145 BC (10.3%) 1130 BC 1065 BC ( 0.6%) 1060 BC

Bask. No. 9641

1440 BC (47.0%) 1385 BC 1495 BC ( 3.1%) 1480 BC

RT-3030 L.1149-1 -22.5 3125 ± 35

1340 BC (21.2%) 1310 BC 1460 BC (92.3%) 1290 BC

Str. Acr-III

Bask. No. 9716 1390 BC (16.7%) 1340 BC

1370 BC ( 2.7%) 1365 BC

RT-3031 L.1171-2 -21.7 3020 ± 25 1315 BC (77.9%) 1195 BC

1290 BC (65.5%) 1220 BC

Str. Acr-III 1140 BC ( 0.9%) 1135 BC

Bask. No. 10817

1195 BC (16.2%) 1145 BC

RT-3032 L.1149-1 -23.5 2910 ± 20 1125 BC (68.2%) 1050 BC

1130 BC (79.2%) 1020 BC

Str. Acr-III

 

Table 23.2. Wood charcoal samples measured by decay counting method by I. Carmi.

For these samples the stable isotope ratio 13 δC was determined by conventional mass spectrometry.

23 . THE RADIOCARBON SAMPLES FROM THE ACROPOLIS OF TEL YARMUTH 505

 

Lab # Field ID Type Calibrated range ± 1 σ Eff. 14 C C age Calibrated range ± 2σ

% % year BP

 

RTD-6998.2 Bask. No. 10888, 2900 ± 40 Olive RTD-6998.1

1195 BC ( 9.0%) 1140 BC

L.1149-floor a 66 76.7 2880 ± 40 1120 BC (68.2%) 1020 BC

RTD-6998 pit 1130 BC (86.4%) 980 BC

Str. Acr-III 2890 ± 29

combine

Bask. No. 9649, 1380 BC ( 4.4%) 1345 BC

Olive 1260 BC (68.2%) 1125 BC

RTD-6997 L.1149-floor b 63 80.0 2975 ± 45 1305 BC (91.0%) 1050 BC

pit

Str. Acr-III

Bask. No. 9653,

Olive 980 BC (52.4%) 890 BC

RTD-6702 L.1150, floor a 70 83.6 2775 ±45 1025 BC (95.4%) 820 BC

pit 880 BC (15.8%) 845 BC

Str. Acr-IV

Bask. No. 10621, 1270 BC (58.0%) 1155 BC 1380 BC ( 5.3%) 1345 BC

RTD-6999 L.1186-layer 1 Seed 35 74.6 2985 ± 40 1150 BC (10.2%) 1130 BC 1305 BC (90.1%) 1055 BC

Str. Acr-V

1375 BC ( 6.9%) 1355 BC

Bask. No. 10659, 1390 BC (15.7%) 1335 BC

Olive 1300 BC (58.9%) 1195 BC

RTD-6700 L.1186-floor a 27 77.0 3010 ± 40 1325 BC (79.7%) 1125 BC

pit 1140 BC ( 2.3%) 1135 BC

Str. Acr-V

Bask. No. 10683, 1110 BC ( 4.5%) 1100 BC

Olive 1195 BC ( 6.4%) 1140 BC

RTD-6701 L.1186-floor b 36 76.4 2855 ±50 1090 BC (54.2%) 970 BC

pit 1135 BC (89.0%) 900 BC

Str. Acr-V 960 BC ( 9.5%) 935 BC

 

Table 23.3. Short lived samples measured by AMS by E. Boaretto. Pre-treatment data together with the sample archaeological information, radiocarbon age and calibrated ranges are presented. The

samples are ordered according to the stratigraphic sequence.

 

23.2. DISCUSSSION

 

The calibrated ranges in year BC are presented in Fig. 23.1 and are ordered according to

the stratigraphic sequence, from the oldest, at the bottom, and the youngest, at the top. Sam-

ples of wood charcoal are represented in black, while short lived (seed and olive pit) are

shown in green.

According to the archaeological context and stratigraphy:

– Samples from Stratum Acr-III (RT-3029, RT-3030, RT-3031, RT-3032, RTD-6998

and RTD-6997) were expected to date in the 11th century BC;

– The single sample from Stratum Acr-IV (RTD- 6702) was expected to date at the end

of 12th century BC;

– Samples from Stratum Acr-V (RTD-6999, RTD- 6700 and RTD- 6701) were expected

to date in the middle of the 12th century BC.

In general, there is poor agreement between the archaeological expected age and the cali-

brated radiocarbon dates. In Stratum Acr-III only two, RT-3032 and RTD-6998, out of

six samples are in the expected 11th century BC range. The three charcoal samples,

RT-3029, RT-3030 and RT-3031, are older than expected, but it could be due to the so

called “old wood effect”, as the possibility exists that the tree had a significant age when it

was cut for presumably building purposes in antiquity. Also, the re-use of beam for con-

506 E. BOARETTO

 

struction is a possibility that should be considered. The short-lived sample, RTD-6997,

could possibly be also in the 11th century BC considering the ±2 σ calibrated range.

Stratum Acr-IV is represented by a single sample, RTD-6702, which is definitely much

later in the 10th and 9th century BC. This olive pit must be an intrusive sample in the

context.

Stratum Acr-V has three samples, of which only one (RTD-6999) is in the middle of the

12th century BC. Samples RTD-6700 and RTD-6701 are respectively too old and too

 

Fig. 23.1. Probability distribution of the calibrated ranges of the dated samples. The order is according to stratigraphy, from the earliest (bottom) to the latest (top). The calibrated ranges for the ±1 σ standard deviation (68.2% probability that the right time is included in the interval) and the ±2σ standard deviation (94.5% probability) are indicated below the probability distribution curves as segments. The segment related to ±1σ is the internal one, and the segment related to ±2σ is

the external one.

23 . THE RADIOCARBON SAMPLES FROM THE ACROPOLIS OF TEL YARMUTH 507

 

young in comparison to the expected age, although they cover the middle of the 12th cen-

tury BC if the ±2 σ range would be considered.

Based on these set of dates, it would be very difficult to build a chronological frame for

the Tel Yarmuth Iron Age acropolis. These dates are not in agreement with their strati-

graphic sequence or the expected ages. At large they cover the time frame associated to the

cultural material, but it would be difficult to give more precise ranges. If renewed excavation

uncovers good contexts with dateable material, then an improvement of the chronology will

be possible.

 

REFERENCES

 

BRONK RAMSEY, C.

2001 “Development of the radiocarbon calibration program OxCal,” Radiocarbon, 43(2A):

355–363.

REGEV, L., STEIER, P., SHACHAR, Y., MINTZ, E., WILD, E. M., KUTSCHERA, W. and BOARETTO, E.

2017 “D-REAMS: A new compact AMS for Radiocarbon measurements at the Weizmann

Institute of Science, Rehovot, Israel,” Radiocarbon 59(3): 775–784.

REIMER, P. J., BARD, E., BAYLISS, A., BECK, J. W., BLACKWELL, P. G., BRONK RAMSEY, C., GROOTES, P. M., GUILDERSON, T. P., HAFLIDASON, H., HAJDAS, I., HATTÉ, C., HEATON, T. J., HOFFMANN, D. L., HOGG, A. G., HUGHEN, K. A., KAISER, K. F., KROMER, B., MANNING, S. W., NIU, M., REIMER, R. W., RICHARDS, D. A., SCOTT, E. M., SOUTHON, J. R., STAFF, R. A., TURNEY, C. S. M. and VAN DER PLICHT, J.

2013 “IntCal13 and Marine13 Radiocarbon Age Calibration Curves 0-50,000 Years

Cal BP,” Radiocarbon 55(4): 1869–1887.

YIZHAQ, M., MINTZ, G., COHEN, I., KHALAILY, H., WEINER, S. and BOARETTO, E.

2005 “Quality Controlled Radiocarbon Dating of Bones and Charcoal from the early

Pre-Pottery Neolithic B (PPNB) of Motza (Israel),” Radiocarbon 47(2): 193–206.