31st International Symposium on Archaeometry Budapest, 27 April 1 May 1998


Analysis of some Metallic Objects from the Necropolis of Saticula (Sant'Agata Dei Goti, Benevento, Italy)



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10. Analysis of some Metallic Objects from the Necropolis of Saticula (Sant'Agata Dei Goti, Benevento, Italy)


Giuseppina Balassone*, Giovanni Di Maio**, Maria Boni*, Maria Fariello***

*Dipartimento di Scienze della Terra Universitá di Napoli

**GEOMED S.A.S.

***Sovrintendenza Archeologica per le province di Salerno, Avellino e Benevento

In some of the tombs (T. 26 and T. 139) of the Sannitic necropolis of Saticula (Sant'Agata dei Goti, Benevento), spanning in age between the 6th and the 4th century B.C., a few very peculiar rings have been found, made of a dark, partly altered metal alloy, and with a circular or ellipsoidal setting hosting various figures in relief (athlete, running animal, human face etc.). More in particular, owing to their association with well dated ceramic material, the rings can be assigned to the second half of the 4th century B.C.

On these objects several types of chemical and mineralogical studies have been performed, ranging from X-ray diffractometry, to SEM and Electron Microprobe semiquantitative and punctual quantitative analysis, in order to investigate the nature (and the proportions) of the metals present in the alloy, as well as their alteration products. On the following Table are listed the more characteristic compositions recorded on some of the analyzed ring fragments.







A

B

C

D

E

Pb

94.95

94.9

82.01

0.71

95.75

Total

96.82*

99.07

97.32*

100.14

100.4

* some Pb can be found as oxides, carbonates etc.


A: bronze-coloured matrix

B: silver-grey areas at the border of A

C: dark-grey areas with high relief

D: inclusions in A with very high reflectivity

E: punctual analyses in A with variable chemical composition

As can be seen, the alloy consists mainly of Pb, in dominant proportion on Sn, less Ag (probably associated to Sn) and sporadic Cu. The proportion of tin in the alloy, however, is not always constant, ranging from an average of few % to almost 100% in selected areas of the rings, probably due to immiscibility processes during imperfect smelting.


11. Geophysical Studies of Archaeological Structures under the Pavement at Mexico City


Luis Barba, Agustin Ortiz

Laboratorio de Prospección Arqueológica, Instituto de Investigaciones Antropológicas, UNAM. Ciudad Universitaria. México D.F. 05410, email: barba@servidor.unam.mx, Tel/Fax: (5)622-9651

Old cities around the world share problems like the overlapping of several cultural layers. This implies the question, how to study previous structures preserving modern constructions? High resolution geophysical techniques provide some answers. Preserving buildings on top, geophysics supply information concerning extension and depth of buried structures. This kind of information leads subsequent archaeological excavations to verify and obtain detailed information.

Mexico City is one of these cities. Prehispanic settlements are under the pavement of the present urban development. Studies performed at Coyoacan have demonstrated that topographic, magnetic, electric and radar surveys can identify the presence of buried structures under the pavement, even though there is some degree of interference characteristic of urban environment. This synoptic approach, where techniques complement each other, permits a better and more confident interpretation of geophysical results.


12. Some Analyses of Glazes from Assur in Mesopotamia/Iraq


Hans-Georg Bartel, Horst Hennig, Günter Kauschka

Humboldt University Berlin, Institute of Chemistry

The Berlin Vorderasiatisches Museum SMPK has a large collection of objects from excavations at Assur in Mesopotamia/Iraq, operated by Walter Andrae and his team between 1903 and 1914. Several glazes of objects from this collection were studied:

Old-Assyrian spacer beans (glazed sintered quartz, 18th century BC)

Neo-Assyrian glazed pottery and knob plates (10th – 7th century BC)

Fragments of Parthian sarcophagus lids (2nd century BC – 3rd century AD)

The aim of this study is to compare glazes from Assur produced in different pre-Islamic periods with those of other sites in ancient Mesopotamia. The composition of the glazes and the chemical nature of their colorants were of specific interest.

The studies were carried out using a Akashi Alpha-9 scanning electron microscopy (SEM) fitted with a qualitative energy-dispersive Röntec X-ray spectrometer (EDX).

The results obtained are:

(i) Generally, the compositions of the Assur glazes produced in periods (b) and (c) are similiar to those ones excavated in Nippur [2], Nimrud [3], Kish [4], Niniveh[4], Uruk[5]. They are all alkaline glazes. The presence of lead in yellow samples is due to its use as a colorant.

(ii) The methods of glazing are the application of glaze at the time of (b) or (c) and self-glazing at the time (a).

(iii) Green and blue glazes are always coloured by CuO, yellow ones by PbO, and black ones by MnO/FeO. Silica was only used as colorant and opacifier in white glazes. Red coloured parts observed in green glazed Parthian sarcophagi are caused by hematite crystals.

As an example, the comparison of Parthian glazes from Assur with some other glazes produced in Mesopotamia is shown in the following table:

Average composition (wt-%) for some glazes of Mesopotamia



site/time/reference

SiO2

Al2O3

Na2O

K2O

CaO

MgO

Cl

SO3

P2O5

Fe2O3

CuO

Assur/Parthian

66

4

11

4

7

4

1

1

tr

2

<1

Nippur/1400 BC/[2]

64

2

14

2

6

6




1




1

3

Uruk/201 BC/[5]



65

3

9

2

7

5

1

1

2

2

2

Kish/Parthian/[4]

70–75

4

7

2

6

4










3




Niniveh/Parthian/[4]

70–75

4

6

4

4

2
















References:

W. Andrae, Das wiedererstandene Assur. München 1977; Coloured Ceramics from Assur and Earlier Ancient Assyrian Wall-Paintings. London 1925.

B. Neumann, Z. angew. Chem. 42 (1939), 835.

W.E.S. Turner, Iraq 17 (1955), 57.

R.E.M. Hedges: Early Glazed Pottery and Faience in Mesopotamia. In: Th.A. Wertime, St.F. Wertime (eds.): Early Pyrotecnology. The Evolution of the First Fire-Using Industries, Smithonian 1982, 93–103.

H.-G. Bartel, H. Hennig, A. Unger, Ch. Goedicke: Zur chemisch-analytischen Untersuchung von Glasurproben aus dem Rš- und Irigal-Bezirk. In: A. Kose (ed.): Deutsches Archäologisches Institut, Ausgrabungen in Uruk/Warka, Endberichte 17, Architektur IV, Von der Seleukiden- bis zur Sasanidenzeit, Berlin 1997, in press.

These studies were supported by Deutsche Forschungsgemeinschaft



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