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IX International Symposium/XIX Nacional Meeting on Solid State Dosimetry
Mexico city, Aug. 29th – Sept. 1st.
13
DATING ARCHEOLOGICAL CERAMICS FROM THE VALLEY OF VITOR-
AREQUIPA BY THE THERMOLUMINESCENCE (TL) METHOD
N. F. Cano† , E. Cuevas Arizaca*, J.S. Ayala A* , J. M. Yauri†, and S. Watanabe†
†Institute of Physics, University of São Paulo, CP 66318, 05315-970, São Paulo-SP, Brazil
*University of San Agustín of Arequipa, Av. Independencia S/N, Arequipa, Perú
Abstract: In this work, we determined the age of an ancient pottery from the Valley of
Vitor in the region of Arequipa-Peru by the thermoluminescence method.
For dating 325°C TL peak was used and irradiation with γ-dose from 5 to 500 Gy
was carried out for the additive method and from 0.4 to 5 Gy for the regeneration method.
For these dose-values the TL intensity grows linearly, and we obtained the accumulated
dose of Dac = (1.62±0.09) Gy and Dac = (1.36±0.03) Gy for the additive and regeneration
method, respectively.
The age (E) of the sample was calculated by the two methods, being E = (984±184)
years A.C. for the additive method and, E = (1073±146) years A.C. for the regeneration
method. Both results are within 800 to 1200 years, which is period of the Wari culture.
Keywords: Thermoluminescence Dating; Ceramics; Quartz
1 Introduction
The northern Peru was intensely investigated by archaeologists and pre-historians; but that
is not the case of southern Perú. The cultural influence known until today, is mainly due to
historians and one of the first works on the culture of Arequipa is due to J. Haeberli [1],
who investigated seven typical textiles found in Siguas and Vitor Valley, close to Arequipa
City. Haerberli dated these textiles by C-14 method and concluded that they belong to the
early civilization. The present work proposes a study of an ancient pottery found in the
Valley of Vitor using the thermoluminescence dating method, and this is the first time that
the luminescence method is used in dating ceramics from South of Peru.
The Valley of Vitor is located 60 km northeast of the City of Arequipa, Peru. The
history tells that Arequipa has been under influences of two important cultures, Wari and
Tiahuanaco, in development stage called the Middle Horizon.
IX International Symposium/XIX Nacional Meeting on Solid State Dosimetry
Mexico city, Aug. 29th – Sept. 1st.
14
The Wari Culture developed in Huanta, Ayacucho country, between the years 800
to 1200 A.C. approximately. After this period, the empire extended to Cajamarca and
Lambayeque to the North and to Cuzco and Arequipa in the East. The origin of the culture
is a result of the mixture of Nazcas and Huarpas cultures [2].
The ceramics of the Wari culture was influenced predominately in the coloration by
the so called “Tiahuanaco coastal” of Nazca resulting a reciprocal cultural contributions.
The Wari Culture belongs to the Middle Horizon and is divided into different
periods. In the last periods it underwent a crisis, as result of the internal fights resulting in
an administrative dispersion in many localities. Consequently, the Chuquibamba society
arises in the South coast, developing another society that was the continuation of Wari in its
economic structure and customs, occupying mainly some Valleys of the country of
Arequipa (Siguas, Lluta, Majes, Colca, Ocoña and Cotahuasi). This society did not have
know of agricultural production but it had especial technique ceramics in quadrangular
form with red, white, black, yellow, green and predominately the orange color, and
emphasizing in its ceramics the typical heritage of the Wari stars of eight ends.
The thermoluminescence (TL) method will be used for the dating of Valley of Vitor
pottery, quartz grains being the TL material to be used in the dating.
2 Materials and experiments
Fragments of ancient potteries were collected at Valley of Vitor. To eliminate
possible sun light effect approximately 1 mm of external layer has been eliminated [3].
After crushing delicately, the powder was sieved to retain grains size between 0.080 and
0.0180 mm in diameter, then it was immersed in a 10% solution of hydrochloric acid for 45
minutes to eliminate as best as possible carbonates and organic materials. After rinsing in
distilled water, the sample was treated in 40% solution of hydrofluoric acid for 30 minutes,
to finally be washed in distilled water. The expected effect of HF is to corrode thin layer of
the surface of quartz grains, in order to clear the surface on one hand and to eliminate αparticles effect [4].
The TL measurements were carried out in a Daybreak TL reader, model 1100, in a
nitrogen atmosphere. A heating rate of 4oC/s was used for TL reading. Each point in the
glow curve is average of 5 reading.
IX International Symposium/XIX Nacional Meeting on Solid State Dosimetry
Mexico city, Aug. 29th – Sept. 1st.
15
The concentration in mol % of K2O was measured in a x-rays fluorescence system
and the concentration of U-238 and of Th-232 were obtained in a α-counter.
3 Results and discussions
Figure 1a shows glow curves of natural and natural plus additional dose samples, that have
been annealed at 240oC to eliminate all the peaks that occur at temperature below 240oC.
Figure 1b shows TL intensity as function of radiation dose, which is a straight line.
The TL values 100, 250 and 500Gy fall on this line and they are not shown. The
accumulated dose or archaeological dose Dac is the intersection of the above line with doseaxis. In the present case, Dac = (1.62±0.09)Gy was obtained.
‘[Insert Figure 1a and Figure 1b]’
Besides the additive method, regenerative method was also used to cross-check the
above result. The powdered sample and treated in acids solution as described materials
section, was annealed at 450oC for 30 minutes to clear previously induced
thermoluminescence and then irradiated to 0.4 up to 5Gy γ-dose. Fig. 2a shows glow curves
registered after 240oC pre-annealing, again to isolate 325oC peak. Fig. 2b presents the TL
intensity vs. Dose. Comparing TL-value of non-annealed natural sample in Fig. 2a and the
straight line in Fig. 2b, the value of Dac=(1.36±0.03)Gy is obtained.
‘[Insert Figure 2a and Figure 2b]’
From K2O content in the pottery, determined by x-rays fluorescence and U-238 and
Th-232 concentrations determined by α-counting an annual dose rate of Dan = (1.42 ± 0.23)
mGy/y was found [5]. Thus, the age (E) of the sample was calculated by the two methods,
being E= (984±184) years A.C. for the additive method and, E= (1073±146) years A.C. for
the regeneration method.
The age found for the pottery samples is approximately 1100 years A. C. ,
indicating that these samples were manufactured in the time when was development the
Wari culture in the south region of Peru. Historical antecedent’s show that in the Valley of
IX International Symposium/XIX Nacional Meeting on Solid State Dosimetry
Mexico city, Aug. 29th – Sept. 1st.
16
Vitor in Arequipa City was development a new society, which was continuation and
conserved all the costumes of the Wari Culture lived development on the called Middle
Horizon ( 800- 1200 A.C.).
Previous Investigations were carried out from typical textiles of the region formed
by Siguas and Vitor, both in Arequipa City. These investigations demonstrated that the first
cultural influence in the Valley of Vitor would be of the cultures belong to the Early
Horizon, that involved the formative period of the Andean world, which did not have a time
of urbanism
4 Conclusions
The two methods used demonstrated that the ceramic obtained of the Valley of
Vitor in the Arequipa City have an age that correspond to the rank belonging to the time
called Middle Horizon, to which one belong the Wari Culture considered one of the most
important cultures of Peru. The age calculated to the ceramic using the TL Dating method
is E=(984±184) year A.C. for the additive dose and E=(1073±146) years A.C. for the
regeneration technique.
Acknowledgements
The authors wish to thank Ms E. Somessari and Mr C. Gaia, Instituto de Pesquisas
Energeticas e Nucleares (IPEN), Brazil, for kindly carrying out the irradiation of the
samples.
References
[1] Haeberli J. (2001) Tiempo y tradición en arequipa, Perú, y el surgimiento de la
cronología del Tema de la Deidad Central, Boletín de Antropolia 5.
[2] Maximo Neyra (1990), Historia General de Arequipa, Fundación MJ Bustamante,
Arequipa.
[3] Aitken M.J. (1985), “Thermoluminiscence Dating”, Academia Press, England.
[4] Shea-Hua Li (2001), Quaternary Science Reviews, 20, 1365.
[5] Ikeya M. (1993), New Applications of Electron Spin Resonance, World Scientific
Publishing.
IX International Symposium/XIX Nacional Meeting on Solid State Dosimetry
Mexico city, Aug. 29th – Sept. 1st.
17
Figures Caption
Figure 1a. Glow curves of samples ceramic irradiated with doses of natural, 5, 10, 25 and
50 Gy, submitted to a pre-heating at 240 oC.
Figure 1b. Growth of the glow curve of the peak of de 330oC as a function of doses.
Figura 2a. Glow curves of samples annealed at 450 oC/30 min and then irradiated to doses
indicated in the figure. The curved is that of non-annealed natural sample.
Figura 2b. Behavior of the of the TL response as function of dose of samples in Figure 2a.
IX International Symposium/XIX Nacional Meeting on Solid State Dosimetry
Mexico city, Aug. 29th – Sept. 1st.
18
150 200 250 300 350 400 450
0
5
10
15
20
25
30
35
40
TL
In te ns ity
(a .u .)
Temperature (oC)
e - Nat + 50 Gy
d - Nat + 25 Gy
c - Nat + 10 Gy
b - Nat + 5 Gy
a - Nat + 0 Gy
a b c d e Figure 1a
0 10 20 30 40 50
0
5
10
15
20
25
30
I(D) = Io + AD
Io = 0.86 ± 0.04
A = 0.53 ± 0.02
Dac = 1.62 ± 0.09T
L
In te ns ity
(a .u .)
Dose (Gy)
Figura 1b
IX International Symposium/XIX Nacional Meeting on Solid State Dosimetry
Mexico city, Aug. 29th – Sept. 1st.
19
150 200 250 300 350 400 450
0,0
0,5
1,0
1,5
2,0
2,5
TL
In te ns ity
(a .u .)
Temperature (oC)
g - 4.0 Gy
f - 3.0 Gy
e - 2.0 Gy
d - natural
c - 1.2 Gy
b - 0.8 Gy
a - 0.4 Gy
a b c d e f g Figura 2a
0 2 4 6
0
1
2
3
TL
In te ns ity
(a .u .)
Dose (Gy)
y=Ax
A=0.502 ± 0.012
DAC=1.36 ± 0.03 Gy
Figura 2b

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